Enter drug's generic or brand name below. Results will appear here. Note: all drug related information obtained on this page is provided by RX List.
Using the RX LIST database:
(1) Enter the drug name in the search box below and hit ENTER
(2) The rx list web site will open here with the drug search completed. Next, scroll down the page to locate the link to the drug you are searching for and then click on the link.
Qsymia capsule is a combination oral product comprised of immediate-release phentermine hydrochloride (expressed as the weight of the free base) and extended-release topiramate. Qsymia contains phentermine hydrochloride, a sympathomimetic amine anorectic, and topiramate, a sulfamate-substituted monosaccharide related to fructose antiepileptic drug.
The chemical name of phentermine hydrochloride is α,α-dimethylphenethylamine hydrochloride. The molecular formula is C10H15N • HCl and its molecular weight is 185.7 (hydrochloride salt) or 149.2 (free base). Phentermine hydrochloride is a white, odorless, hygroscopic, crystalline powder that is soluble in water, methanol, and ethanol. Its structural formula is:
 |
Topiramate is 2,3:4,5-di-O-isopropylidene-β-D-fructopyranose sulfamate. The molecular formula is C12H21NO8S and its molecular weight is 339.4. Topiramate is a white to off-white crystalline powder with a bitter taste. It is freely soluble in methanol and acetone, sparingly soluble in pH 9 to pH 12 aqueous solutions and slightly soluble in pH 1 to pH 8 aqueous solutions. Its structural formula is:
 |
Qsymia is available in four dosage strengths:
Each capsule contains the following inactive ingredients: methylcellulose, sucrose, starch, microcrystalline cellulose, ethylcellulose, povidone, gelatin, talc, titanium dioxide, FD&C Blue #1, FD&C Red #3, FD&C Yellow #5 and #6, and pharmaceutical black and white inks.
The following clinically significant adverse reactions are described elsewhere in the labeling:
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.
The data described herein reflect exposure to QSYMIA in two 1-year, randomized, double-blind, placebocontrolled, multicenter clinical trials and two supportive trials in 2,318 adult patients with overweight or obesity [936 (40%) patients with hypertension, 309 (13%) patients with type 2 diabetes mellitus, 808 (35%) patients with BMI greater than 40 kg/m2] exposed for a mean duration of 298 days. Data in this section also describe adverse reactions from a 1-year, randomized, double-blind, placebo-controlled multicenter clinical trial that evaluated 223 pediatric patients (12 to 17 years old) with obesity [see Clinical Studies (14)].
Adverse reactions occurring at greater than or equal to 5% and at least 1.5 times placebo in adults include paraesthesia, dizziness, dysgeusia, insomnia, constipation, and dry mouth.
Adverse reactions reported in greater than or equal to 2% of QSYMIA-treated adults and more frequently than in the placebo group are shown in Table 1.
Table 1. Adverse Reactions Reported in ≥2% of QSYMIA-Treated Adults with Overweight or Obesity and More Frequently than Placebo in Overall Study Population of 1 Year Duration
| Adverse Reaction | Placebo (N = 1561) % |
QSYMIA 3.75 mg/23 mg (N = 240) % |
QSYMIA 7.5 mg/46 mg (N = 498) % |
QSYMIA 15 mg/92 mg (N = 1,580) % |
| Paraesthesia | 2 | 4 | 14 | 20 |
| Dry Mouth | 3 | 7 | 14 | 19 |
| Constipation | 6 | 8 | 15 | 16 |
| Upper Respiratory Tract Infection | 13 | 16 | 12 | 14 |
| Headache | 9 | 10 | 7 | 11 |
| Dysgeusia | 1 | 1 | 7 | 9 |
| Insomnia | 5 | 5 | 6 | 9 |
| Nasopharyngitis | 8 | 13 | 11 | 9 |
| Dizziness | 3 | 3 | 7 | 9 |
| Sinusitis | 6 | 8 | 7 | 8 |
| Nausea | 4 | 6 | 4 | 7 |
| Back Pain | 5 | 5 | 6 | 7 |
| Fatigue | 4 | 5 | 4 | 6 |
| Diarrhea | 5 | 5 | 6 | 6 |
| Vision Blurred | 4 | 6 | 4 | 5 |
| Bronchitis | 4 | 7 | 4 | 5 |
| Urinary Tract Infection | 4 | 3 | 5 | 5 |
| Cough | 4 | 3 | 4 | 5 |
| Influenza | 4 | 8 | 5 | 4 |
| Depression | 2 | 3 | 3 | 4 |
| Anxiety | 2 | 3 | 2 | 4 |
| Hypoesthesia | 1 | 1 | 4 | 4 |
| Irritability | 1 | 2 | 3 | 4 |
| Alopecia | 1 | 2 | 3 | 4 |
| Disturbance in Attention | 1 | 0 | 2 | 4 |
| Pain in Extremity | 3 | 2 | 3 | 3 |
| Muscle Spasms | 2 | 3 | 3 | 3 |
| Dyspepsia | 2 | 2 | 2 | 3 |
| Gastroesophageal Reflux Disease | 1 | 1 | 3 | 3 |
| Rash | 2 | 2 | 2 | 3 |
| Hypokalemia | 0 | 0 | 1 | 3 |
| Dry Eye | 1 | 1 | 1 | 3 |
| Gastroenteritis | 2 | 1 | 2 | 3 |
| Pharyngolaryngeal Pain | 2 | 3 | 1 | 2 |
| Paraesthesia Oral | 0 | 0 | 1 | 2 |
| Eye Pain | 1 | 2 | 2 | 2 |
| Nasal Congestion | 1 | 2 | 1 | 2 |
| Thirst | 1 | 2 | 2 | 2 |
| Sinus Congestion | 2 | 3 | 3 | 2 |
| Procedural Pain | 2 | 2 | 2 | 2 |
| Palpitations | 1 | 1 | 2 | 2 |
| Musculoskeletal Pain | 1 | 1 | 3 | 2 |
| Decreased Appetite | 1 | 2 | 2 | 2 |
| Neck Pain | 1 | 1 | 2 | 1 |
| Dysmenorrhea | 0 | 2 | 0 | 1 |
| Chest Discomfort | 0 | 2 | 0 | 1 |
Adverse reactions occurring in pediatric patients treated with either QSYMIA 15 mg/92 mg or QSYMIA 7.5 mg/46 mg at greater than or equal to 4% and higher than placebo include depression, pyrexia, dizziness, arthralgia, influenza, and ligament sprain.
Adverse reactions reported in greater than or equal to 2% of QSYMIA-treated pediatric patients and more frequently than in the placebo group from a study in pediatric patients aged 12 years and older are shown in Table 2.
Table 2. Adverse Reactions Reported in ≥2% of QSYMIA-Treated Pediatric Patients Aged 12 to 17 Years and More Frequently than Placebo during 56 Weeks of Treatment
| Adverse Reaction | Placebo (N = 56) % |
QSYMIA 7.5 mg/46 mg (N = 54) % |
QSYMIA 15 mg/92 mg (N = 113) % |
| Depression | 0 | 2 | 4 |
| Nausea | 4 | 4 | 4 |
| Pyrexia | 2 | 2 | 4 |
| Dizziness | 0 | 2 | 4 |
| Arthralgia | 0 | 2 | 4 |
| Paraesthesia | 0 | 2 | 3 |
| Anxiety | 0 | 2 | 3 |
| Abdominal Pain Upper | 0 | 0 | 3 |
| Fatigue | 2 | 0 | 3 |
| Ear Infection | 0 | 2 | 3 |
| Musculoskeletal Chest Pain | 0 | 0 | 3 |
| Influenza | 0 | 4 | 2 |
| Ligament Sprain | 0 | 4 | 2 |
In adult and pediatric clinical trials, there was a higher incidence of heart rate elevations observed in QSYMIAtreated compared to placebo-treated patients. In an 8-week ambulatory blood pressure monitoring (ABPM) study in adults, QSYMIA increased the 24-hr average heart rate by 3.6 beats per minute (bpm) (95% CI 2.1, 5.2) compared to the placebo group [see Clinical Pharmacology (12.2)].
In clinical trials, a higher percentage of QSYMIA-treated adults and pediatric patients aged 12 years and older experienced heart rate increases from baseline of more than 5, 10, 15, and 20 bpm compared to placebo-treated patients. Table 3 and Table 4 provide the numbers and percentages of adult and pediatric patients, respectively, with elevations in heart rate in clinical studies of up to one year.
Table 3. Number and Percentage of Adults with Overweight or Obesity with an Increase in Heart Rate at a Single Time Point from Baseline
|
Placebo |
QSYMIA |
QSYMIA |
QSYMIA |
|
|
Greater than 5 bpm |
1021 (65.4) |
168 (70.0) |
372 (74.7) |
1228 (77.7) |
|
Greater than 10 bpm |
657 (42.1) |
120 (50.0) |
251 (50.4) |
887 (56.1) |
|
Greater than 15 bpm |
410 (26.3) |
79 (32.9) |
165 (33.1) |
590 (37.3) |
|
Greater than 20 bpm |
186 (11.9) |
36 (15.0) |
67 (13.5) |
309 (19.6) |
Table 4. Number and Percentage of Pediatric Patients with an Increase in Heart Rate at a Single Time Point from Baseline
| Placebo N=56 n (%) |
QSYMIA 7.5 mg/46 mg N=54 n (%) |
QSYMIA 15 mg/92 mg N=113 n (%) |
|
| Greater than 5 bpm | 37 (66.1) | 38 (70.4) | 92 (81.4) |
| Greater than 10 bpm | 26 (46.4) | 30 (55.6) | 73 (64.6) |
| Greater than 15 bpm | 17 (30.4) | 18 (33.3) | 48 (42.5) |
| Greater than 20 bpm | 10 (17.9) | 10 (18.5) | 27 (23.9) |
In adult clinical trials, reports of paraesthesia, characterized as tingling in hands, feet, or face, and dysgeusia, characterized as a metallic taste, occurred (see Table 1). Adverse reactions of paraesthesia were also reported in pediatric patients (see Table 2). QSYMIA-treated adult patients discontinued treatment due to these adverse reactions (1% for paraesthesia and 0.6% for dysgeusia); no pediatric patients discontinued treatment due to paraesthesia or dysgeusia.
The proportion of adult patients in 1-year controlled trials of QSYMIA reporting one or more adverse reactions related to mood and sleep disorders was 15% and 21% with QSYMIA 7.5 mg/46 mg and 15 mg/92 mg, respectively, compared to 10% with placebo. These events were further categorized into sleep disorders, anxiety, and depression. Reports of sleep disorders were typically characterized as insomnia and occurred in 8.1% and 11% of patients treated with QSYMIA 7.5 mg/46 mg and 15 mg/92 mg, respectively, compared to 5.8% of patients treated with placebo. Reports of anxiety occurred in 4.8% and 7.9% of patients treated with QSYMIA 7.5 mg/46 mg and 15 mg/92 mg, respectively, compared to 2.6% of patients treated with placebo. Reports of depression/mood problems occurred in 3.8% and 7.6% of patients treated with QSYMIA 7.5 mg/46 mg and 15 mg/92 mg, respectively, compared to 3.4% of patients treated with placebo. Mood and sleep disorder adverse reactions occurred in patients with and without a history of depression.
In a pediatric clinical trial, higher proportions of QSYMIA-treated patients reported one or more adverse reactions related to mood (e.g., depression, anxiety) and sleep disorders (e.g., insomnia) compared to placebotreated patients (see Table 2).
In the 1-year controlled trials of QSYMIA in adults, the proportion of patients who experienced one or more cognitive-related adverse reactions was 5.0% for QSYMIA 7.5 mg/46 mg and 7.6% for QSYMIA 15 mg/92 mg, compared to 1.5% for placebo. These adverse reactions were comprised primarily of reports of problems with attention/concentration, memory, and language (word-finding). These events occurred at any time during treatment with QSYMIA.
QSYMIA is associated with a reduction in height velocity (centimeters of height gained per year) in obese pediatric patients 12 to 17 years of age. In a 56-week study, average height increased from baseline in both QSYMIA- and placebo-treated patients; however, a lower height velocity of -1.3 to -1.4 cm/year was observed in QSYMIA-treated compared to placebo-treated patients.
QSYMIA is associated with less bone mineral acquisition in pediatric patients 12 to 17 years of age. In a substudy (n=66) evaluating bone mineralization via dual-energy X-ray absorptiometry (DEXA), increases in bone mineral density (BMD) at the lumbar spine and total body less head (TBLH) were smaller in pediatric patients treated with QSYMIA compared to those treated with placebo after 1 year of treatment. Declines in BMD Z-scores of -0.5 or greater from baseline for TBLH were observed in 9% of QSYMIA 7.5 mg/46 mgtreated patients and 30% of QSYMIA 15 mg/92 mg-treated patients, compared to 0% of placebo-treated patients. The sample size and study duration were too small to determine if fracture risk is increased. Decreased BMD was not correlated with decreased serum bicarbonate, which commonly occurs with QSYMIA treatment, or changes in body weight. No patient had a BMD Z-score that went below -2.0 during the trial. Similar findings were observed in a 1 year, active-controlled trial of topiramate in pediatric patients with another condition.
In the 1-year controlled trials of QSYMIA in adults, the incidence of nephrolithiasis was 0.2% for QSYMIA 7.5 mg/46 mg and 1.2% for QSYMIA 15 mg/92 mg, compared to 0.3% for placebo.
Serum Bicarbonate
In the 1-year controlled trials of QSYMIA in adults, the incidence of persistent decreases in serum bicarbonate below the normal range (levels of less than 21 mEq/L at 2 consecutive visits or at the final visit) was 6.4% for QSYMIA 7.5 mg/46 mg and 12.8% for QSYMIA 15 mg/92 mg, compared to 2.1% for placebo. The incidence of persistent, markedly low serum bicarbonate values (levels of less than 17 mEq/L on 2 consecutive visits or at the final visit) was 0.2% for QSYMIA 7.5 mg/46 mg dose and 0.7% for QSYMIA 15 mg/92 mg dose, compared to 0.1% for placebo. In a pediatric clinical trial, 60 to 70% QSYMIA-treated patients had a persistent bicarbonate level below the normal range (<21 mEq/L) compared to 43% of placebo-treated patients.
Serum Potassium
In the 1-year controlled trials of QSYMIA in adults, the incidence of persistent low serum potassium values (less than 3.5 mEq/L at two consecutive visits or at the final visit) during the trial was 3.6% for QSYMIA 7.5 mg/46 mg dose and 4.9% for QSYMIA 15 mg/92 mg, compared to 1.1% for placebo. Of the subjects who experienced persistent low serum potassium, 88% were receiving treatment with a non-potassium sparing diuretic.
The incidence of markedly low serum potassium (less than 3 mEq/L, and a reduction from pre-treatment of greater than 0.5 mEq/L) at any time during the trial was 0.2% for QSYMIA 7.5 mg/46 mg dose and 0.7% for QSYMIA 15 mg/92 mg dose, compared to 0.0% for placebo. Persistent markedly low serum potassium (less than 3 mEq/L, and a reduction from pre-treatment of greater than 0.5 mEq/L at two consecutive visits or at the final visit) occurred in 0.2% receiving QSYMIA 7.5 mg/46 mg dose and 0.1% receiving QSYMIA 15 mg/92 mg dose, compared to 0.0% receiving placebo.
Low serum potassium levels (<3.5 mEq/L) were not observed in a 56-week clinical trial of pediatric patients with obesity.
Serum Creatinine
In the 1-year controlled trials of QSYMIA in adults and pediatric patients, there was an increase in serum creatinine from baseline, peaking between Week 4 to 8 in adults and at Week 16 in pediatric patients. Serum creatinine values declined but remained elevated over baseline over 1 year of treatment. The incidence of increases in serum creatinine of greater than or equal to 0.3 mg/dL at any time during treatment in adults was 7.2% for QSYMIA 7.5 mg/46 mg and 8.4% for QSYMIA 15 mg/92 mg, compared to 2.0% for placebo; 17% of pediatric patients treated with QSYMIA 7.5 mg/46 mg or QSYMIA 15 mg/92 mg and 0% of patients treated with placebo had a serum creatinine ≥0.3 mg/dL at any time post-randomization. Increases in serum creatinine of greater than or equal to 50% over baseline occurred in 2.0% of adult subjects receiving QSYMIA 7.5 mg/46 mg and 2.8% receiving QSYMIA 15 mg/92 mg, compared to 0.6% receiving placebo.
Serum Ammonia
Hyperammonemia with or without encephalopathy has been reported with topiramate. The risk for hyperammonemia with topiramate appears dose related and has been reported more frequently when concomitantly used with valproic acid [see Drug Interactions (7)].
The incidence of hyperammonemia in pediatric patients 12 to 17 years of age in clinical trials of another condition was 26% in patients taking topiramate at 100 mg/day (1.1 times the maximum recommended dosage of QSYMIA) and 14% in patients taking topiramate at 50 mg/day (0.6 times the maximum recommended dosage of QSYMIA), compared to 9% in patients taking placebo. There was also an increased incidence of markedly increased hyperammonemia (defined as 50% above the upper limit of normal reference range) at the 100 mg dose.
The following adverse reactions have been reported during post approval use of QSYMIA, phentermine, and topiramate. Because these reactions are reported voluntarily from a population of uncertain size it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Psychiatric: suicidal ideation, suicidal behavior
Ophthalmic: acute angle closure glaucoma, increased intraocular pressure
Allergic Reactions: urticaria
Cardiovascular: elevation of blood pressure, ischemic events
Central Nervous System: euphoria, psychosis, tremor
Reproductive: changes in libido, impotence
Dermatologic: bullous skin reactions (including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis), pemphigus
Gastrointestinal: pancreatitis
Hepatic: hepatic failure (including fatalities), hepatitis
Metabolic: hyperammonemia with or without encephalopathy has been reported with concomitant valproic acid [see Drug Interactions (7)], hypothermia
Ophthalmic: maculopathy
Table 5 displays clinically significant drug interactions with QSYMIA.
Table 5. Clinically Significant Drug Interactions with QSYMIA
|
Monoamine Oxidase Inhibitors |
|
|
Clinical Impact |
Concomitant use of phentermine with monoamine oxidase inhibitors (MAOIs) increases the risk of hypertensive crisis. |
|
Intervention |
Concomitant use of QSYMIA is contraindicated during MAOI treatment and within 14 days of stopping an MAOI. |
|
Oral Contraceptives |
|
|
Clinical Impact |
Co-administration of multiple-dose QSYMIA 15 mg/92 mg once daily with a single dose of oral contraceptive containing 35 µg ethinyl estradiol (estrogen component) and 1 mg norethindrone (progestin component), in obese otherwise healthy volunteers, decreased the exposure of ethinyl estradiol by 16% and increased the exposure of norethindrone by 22% [see Clinical Pharmacology (12.3)]. Although this interaction is not anticipated to increase the risk of pregnancy, irregular bleeding (spotting) may occur more frequently due to both the increased exposure to the progestin and lower exposure to the estrogen, which tends to stabilize the endometrium. |
|
Intervention |
Inform patients not to discontinue their combination oral contraceptive if spotting occurs, but to notify their health care provider if the spotting is troubling to them. |
|
CNS Depressants Including Alcohol |
|
|
Clinical Impact |
The concomitant use of alcohol or CNS depressant drugs (e.g., barbiturates, benzodiazepines, and sleep medications) with phentermine or topiramate may potentiate CNS depression such as dizziness or cognitive adverse reactions, or other centrally mediated effects of these agents. |
|
Intervention |
Advise patients not to drive or operate machinery until they have gained sufficient experience on QSYMIA to gauge whether it adversely affects their mental performance, motor performance, and/or vision. Caution patients against excessive alcohol intake when taking QSYMIA. Consider QSYMIA dosage reduction or discontinuation if cognitive dysfunction persists [see Warnings and Precautions (5.5)] |
|
Non-Potassium Sparing Diuretics |
|
|
Clinical Impact |
Concurrent use of QSYMIA with non-potassium sparing diuretics may potentiate the potassium-wasting action of these diuretics. Concomitant administration of hydrochlorothiazide alone with topiramate alone has been shown to increase the Cmax and AUC of topiramate by 27% and 29%, respectively. |
|
Intervention |
When QSYMIA is used concomitantly with non-potassium-sparing diuretics, measure potassium before and during QSYMIA treatment [see Warnings and Precautions (5.12) and Clinical Pharmacology (12.3)]. |
|
Antiepileptic Drugs |
|
|
Clinical Impact |
Concomitant administration of phenytoin or carbamazepine with topiramate in patients with epilepsy, decreased plasma concentrations of topiramate by 48% and 40%, respectively, when compared to topiramate given alone [see Clinical Pharmacology (12.3)]. Concomitant administration of valproic acid and topiramate has been associated with hyperammonemia with and without encephalopathy. Concomitant administration of topiramate with valproic acid in patients has also been associated with hypothermia (with and without hyperammonemia). |
|
Intervention |
Consider measuring blood ammonia in patients in whom the onset of hypothermia or encephalopathy has been reported [see Clinical Pharmacology (12.3)]. |
|
Carbonic Anhydrase Inhibitors |
|
|
Clinical Impact |
Concomitant use of topiramate with any other carbonic anhydrase inhibitor may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. |
|
Intervention |
Avoid the use of QSYMIA with other drugs that inhibit carbonic anhydrase. If concomitant use of QSYMIA with another carbonic anhydrase inhibitor is unavoidable, monitor patient for the appearance or worsening of metabolic acidosis [see Warnings and Precautions (5.7, 5.10)]. |
|
Pioglitazone |
|
|
Clinical Impact |
A decrease in the exposure of pioglitazone and its active metabolites were noted with the concurrent use of pioglitazone and topiramate in a clinical trial. The clinical relevance of these observations is unknown. |
|
Intervention |
Consider increased glycemic monitoring when using pioglitazone and QSYMIA concomitantly [see Clinical Pharmacology (12.3)]. |
|
Amitriptyline |
|
|
Clinical Impact |
Some patients may experience a large increase in amitriptyline concentration in the presence of topiramate. |
|
Intervention |
Any adjustments in amitriptyline dose when used with QSYMIA should be made according to the patient's clinical response and not on the basis of amitriptyline levels [see Clinical Pharmacology (12.3)]. |
QSYMIA contains phentermine, a Schedule IV controlled substance, and topiramate, which is not a controlled substance.
Phentermine has a known potential for abuse. Abuse is the intentional, non-therapeutic use of a drug, even once, for its desirable psychological or physiological effects.
Phentermine is related chemically and pharmacologically to amphetamines. Amphetamines and other stimulant drugs have been extensively abused. Abuse of amphetamines and related drugs (e.g., phentermine) may be associated with impaired control over drug use and severe social dysfunction. There are reports of patients who have increased the dosage of these drugs to many times higher than recommended. Assess the risk of abuse prior to prescribing QSYMIA as part of a weight reduction and long-term maintenance of body weight program.
Physical dependence may occur in patients treated with QSYMIA. Physical dependence is a state that develops as a result of physiological adaptation in response to repeated drug use, manifested by withdrawal signs and symptoms after abrupt discontinuation or a significant dose reduction of a drug.
The following adverse reactions have been associated with the abrupt discontinuation of the individual components of QSYMIA:
Thus, in situations where rapid withdrawal of QSYMIA is required, appropriate medical monitoring is recommended. Patients discontinuing QSYMIA 15 mg/92 mg should be gradually tapered to reduce the possibility of precipitating a seizure [see Dosage and Administration (2.3)].
Included as part of the PRECAUTIONS section.
QSYMIA can cause fetal harm. Data from pregnancy registries and epidemiologic studies indicate that a fetus exposed to topiramate in the first trimester of pregnancy has an increased risk of major congenital malformations, including but not limited to cleft lip and/or cleft palate (oral clefts), and of being small for gestational age (SGA). When multiple species of pregnant animals received topiramate at clinically relevant doses, structural malformations, including craniofacial defects, and reduced fetal weights occurred in offspring. A negative pregnancy test is recommended before initiating QSYMIA treatment in patients who can become pregnant and monthly during QSYMIA therapy. Advise patients who can become pregnant of the potential risk to a fetus and to use effective contraception during QSYMIA therapy [see Use in Specific Populations (8.1, 8.3)].
Because of the teratogenic risk associated with QSYMIA therapy, QSYMIA is available through a limited program under the REMS. Under the QSYMIA REMS, only certified pharmacies may distribute QSYMIA. Further information is available at www.QSYMIAREMS.com or by telephone at 1-888-998-4887.
Antiepileptic drugs (AEDs), including topiramate, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Pooled analyses of 199 placebo-controlled clinical studies (monotherapy and adjunctive therapy, median treatment duration 12 weeks) of 11 different AEDs across several indications showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI 1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. The estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in AED-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about AED effect on suicide. The increased risk of suicidal thoughts or behavior with AEDs was observed as early as 1 week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed. The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age in the clinical trials analyzed.
In a QSYMIA clinical trial of pediatric patients aged 12 years and older, 1 (0.6%) of the 167 QSYMIA-treated patients reported suicidal ideation and behavior which required hospitalization. No placebo-treated patients reported suicidal behavior or ideation.
Monitor all patients for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior. Discontinue QSYMIA in patients who experience suicidal thoughts or behaviors [see Warnings and Precautions (5.9)]. Avoid QSYMIA in patients with a history of suicidal attempts or active suicidal ideation.
A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients treated with topiramate. Symptoms include acute onset of decreased visual acuity and/or ocular pain.
Ophthalmologic findings can include myopia, mydriasis, anterior chamber shallowing, ocular hyperemia (redness), choroidal detachments, retinal pigment epithelial detachments, macular striae, and increased intraocular pressure. This syndrome may be associated with supraciliary effusion resulting in anterior displacement of the lens and iris, with secondary angle closure glaucoma. Symptoms typically occur within 1 month of initiating treatment with topiramate but may occur at any time during therapy. In contrast to primary narrow angle glaucoma, which is rare under 40 years of age, secondary angle closure glaucoma associated with topiramate has been reported in pediatric patients as well as adults. The primary treatment to reverse symptoms is discontinuation of QSYMIA as rapidly as possible in consultation with the treating physician. Elevated intraocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent loss of vision.
Visual field defects (independent of elevated intraocular pressure) have been reported in clinical trials and in postmarketing experience in patients receiving topiramate. In clinical trials, most of these events were reversible after topiramate discontinuation. If visual problems occur at any time during treatment, consider discontinuing QSYMIA.
QSYMIA can cause mood disorders, including depression and anxiety, as well as insomnia. Patients with a history of depression may be at increased risk of recurrent depression or other mood disorders while taking QSYMIA [see Adverse Reactions (6.1)].
Consider dosage reduction or discontinuation of QSYMIA if clinically significant or persistent symptoms occur. Discontinue QSYMIA if patients have symptoms of suicidal ideation or behavior [see Warnings and Precautions (5.2)].
QSYMIA can cause cognitive dysfunction (e.g., impairment of concentration/attention, difficulty with memory, and speech or language problems, particularly word-finding difficulties). Rapid titration or high initial doses of QSYMIA may be associated with higher rates of cognitive events such as attention, memory, and language/word-finding difficulties [see Adverse Reactions (6.1)]. The concomitant use of alcohol or central nervous system (CNS) depressant drugs with QSYMIA may potentiate CNS depression or other centrally mediated effects of these agents, such as dizziness, cognitive adverse reactions, drowsiness, lightheadedness, impaired coordination, and somnolence.
Caution patients about operating hazardous machinery, including automobiles, until they are reasonably certain QSYMIA therapy does not affect them adversely. Caution patients against excessive alcohol intake while receiving QSYMIA.
If cognitive dysfunction persists, consider dosage reduction or discontinuation of QSYMIA [see Warnings and Precautions (5.9)].
QSYMIA is associated with a reduction in height velocity (centimeters of height gained per year) in obese pediatric patients 12 to 17 years of age. In a 56-week study, average height increased from baseline in both QSYMIA- and placebo-treated patients; however, a lower height velocity of -1.3 to -1.4 cm/year was observed in QSYMIA-treated compared to placebo-treated patients. Monitor height velocity in pediatric patients treated with QSYMIA. Consider dosage reduction or discontinuation of QSYMIA if pediatric patients are not growing or gaining height as expected [see Warnings and Precautions (5.9)].
Hyperchloremic, non-anion gap, metabolic acidosis (decreased serum bicarbonate below the normal reference range in the absence of chronic respiratory alkalosis) has been reported in patients treated with QSYMIA [see Adverse Reactions (6.1)]. Manifestations of acute or chronic metabolic acidosis may include hyperventilation, nonspecific symptoms such as fatigue and anorexia, or more severe sequelae including cardiac arrhythmias or stupor. Chronic, untreated metabolic acidosis may increase the risk for nephrolithiasis or nephrocalcinosis and may also result in osteomalacia (referred to as rickets in pediatric patients) and/or osteoporosis with an increased risk for fractures. Chronic metabolic acidosis in pediatric patients may also reduce growth rates, which may decrease the maximal height achieved.
Conditions or therapies that predispose to acidosis (i.e., renal disease, severe respiratory disorders, status epilepticus, diarrhea, surgery, or ketogenic diet) may be additive to the bicarbonate lowering effects of QSYMIA. Concomitant use of QSYMIA and a carbonic anhydrase inhibitor may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation [see Warnings and Precautions (5.10)]. Avoid use of QSYMIA with other carbonic anhydrase inhibitors. If concomitant use of QSYMIA with another carbonic anhydrase inhibitor is unavoidable, the patient should be monitored for the appearance or worsening of metabolic acidosis.
Measure electrolytes including serum bicarbonate prior to starting QSYMIA and during QSYMIA treatment. In QSYMIA clinical trials, the peak reduction in serum bicarbonate typically occurred within 4 weeks of titration to the assigned dose, and in most patients, there was a correction of bicarbonate by week 56, without any dosage reduction. However, if persistent metabolic acidosis develops while taking QSYMIA, reduce the dosage or discontinue QSYMIA [see Warnings and Precautions (5.9)].
QSYMIA can cause an increase in serum creatinine that reflects a decrease in renal function (glomerular filtration rate). In clinical trials, peak increases in serum creatinine were observed after 4 to 8 weeks of treatment. On average, serum creatinine gradually declined but remained elevated over baseline creatinine values. The changes in serum creatinine (and measured GFR) with short-term (4-weeks) QSYMIA treatment appear reversible with treatment discontinuation, but the effect of chronic treatment on renal function is not known.
Measure serum creatinine prior to starting QSYMIA and during QSYMIA treatment. If persistent elevations in creatinine occur, reduce the dosage or discontinue QSYMIA [see Warnings and Precautions (5.9), Adverse Reactions (6.1), and Clinical Pharmacology (12.2)].
Abrupt withdrawal of topiramate has been associated with seizures in individuals without a history of seizures or epilepsy. In situations where immediate termination of QSYMIA is medically required, appropriate monitoring is recommended. Patients discontinuing QSYMIA 15 mg/92 mg should be gradually tapered to reduce the possibility of precipitating a seizure [see Dosage and Administration (2.3) and Drug Abuse and Dependence (9.3)].
QSYMIA has been associated with kidney stone formation [see Adverse Reactions (6.1)]. Topiramate inhibits carbonic anhydrase activity and promotes kidney stone formation by reducing urinary citrate excretion and increasing urine pH. Patients on a ketogenic diet may be at increased risk for kidney stone formation. An increase in urinary calcium and a marked decrease in urinary citrate was observed in topiramate-treated pediatric patients in a one-year, active-controlled study. Increased ratio of urinary calcium/citrate increases the risk of kidney stones and/or nephrocalcinosis.
Avoid the use of QSYMIA with other drugs that inhibit carbonic anhydrase [see Drug Interactions (7)]. Advise patients to increase fluid intake (to increase urinary output), which may decrease the concentration of substances involved in kidney stone formation.
Oligohidrosis (decreased sweating), infrequently resulting in hospitalization, has been reported in association with the use of topiramate. Decreased sweating and an elevation in body temperature above normal characterized these cases. Some of the cases have been reported with topiramate after exposure to elevated environmental temperatures.
The majority of the reports associated with topiramate have been in pediatric patients. Advise all patients and caregivers to monitor for decreased sweating and increased body temperature during physical activity, especially in hot weather. Patients on concomitant medications that predispose them to heat-related disorders may be at increased risk.
QSYMIA can increase the risk of hypokalemia through its inhibition of carbonic anhydrase activity. In addition, when QSYMIA is used in conjunction with non-potassium sparing diuretics this may further potentiate potassium-wasting. Measure potassium before and during treatment with QSYMIA [see Adverse Reactions (6.1), Drug Interactions (7), and Clinical Pharmacology (12.3)].
Serious skin reactions (Stevens-Johnson Syndrome [SJS] and Toxic Epidermal Necrolysis [TEN]) have been reported in patients receiving topiramate. QSYMIA should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed, and alternative therapy should be considered. Inform patients about the signs of serious skin reactions.
This product contains FD&C Yellow No. 5 (tartrazine) which may cause allergic-type reactions (including bronchial asthma) in certain susceptible persons. Although the overall incidence of FD&C Yellow No. 5 (tartrazine) sensitivity in the general population is low, it is frequently seen in patients who also have aspirin hypersensitivity.
No animal studies have been conducted with the combination of phentermine/topiramate to evaluate carcinogenesis, mutagenesis, or impairment of fertility. The following data are based on findings in studies performed individually with phentermine or topiramate, QSYMIA’s two active ingredients.
Phentermine was not mutagenic or clastogenic with or without metabolic activation in the Ames bacterial mutagenicity assay, a chromosomal aberration test in Chinese hamster lung (CHL-K1) cells, or an in vivo micronucleus assay.
Rats were administered oral doses of 3, 10, and 30 mg/kg/day phentermine for 2 years. There was no evidence of carcinogenicity at the highest dose of phentermine (30 mg/kg) which is approximately 11 to 15 times the maximum recommended clinical dose of QSYMIA 15 mg/92 mg based on AUC exposure.
No animal studies have been conducted with phentermine to determine the potential for impairment of fertility.
Topiramate did not demonstrate genotoxic potential when tested in a battery of in vitro and in vivo assays. Topiramate was not mutagenic in the Ames test or the in vitro mouse lymphoma assay; it did not increase unscheduled DNA synthesis in rat hepatocytes in vitro; and it did not increase chromosomal aberrations in human lymphocytes in vitro or in rat bone marrow in vivo.
An increase in urinary bladder tumors was observed in mice given topiramate (20, 75, and 300 mg/kg) in the diet for 21 months. The elevated bladder tumor incidence, which was statistically significant in males and females receiving 300 mg/kg, was primarily due to the increased occurrence of a smooth muscle tumor considered histomorphologically unique to mice. Plasma exposures in mice receiving 300 mg/kg were
approximately 2 to 4 times steady-state exposures measured in patients receiving topiramate monotherapy at the MRHD of QSYMIA 15 mg/92 mg. The relevance of this finding to human carcinogenic risk is uncertain. No evidence of carcinogenicity was seen in rats following oral administration of topiramate for 2 years at doses up to 120 mg/kg (approximately 4 to 10 times the MRHD of QSYMIA based on AUC estimates).
No adverse effects on male or female fertility were observed in rats at doses up to 100 mg/kg (approximately 4 to 8 times male and female MRHD exposures of QSYMIA based on AUC).
Advise the patient to read the FDA-approved patient labeling (Medication Guide).
Inform patients who can become pregnant that QSYMIA can cause fetal harm and patients should avoid getting pregnant while taking QSYMIA [see Warnings and Precautions (5.1), Drug Interactions (7), and Use in Specific Populations (8.3)].
Advise patients who can become pregnant:
Advise patients that QSYMIA is only available through certified pharmacies that are enrolled in the QSYMIA certified pharmacy network. Advise patients on how to access QSYMIA through certified pharmacies. Additional information may be obtained via the website www.QSYMIAREMS.com or by telephone at 1-888998-4887.
Inform patients that QSYMIA can increase the risk of mood changes, sleep disorders, depression, and suicidal ideation. Advise patients to tell their health care provider(s) immediately if mood changes, depression, or suicidal ideation occur [see Warnings and Precautions (5.2, 5.4)].
Inform patients that QSYMIA can increase the risk of acute myopia, secondary angle closure glaucoma, and visual field defects. Advise patients to immediately report symptoms of severe and persistent eye pain or significant changes in their vision to their health care provider(s) [see Warnings and Precautions (5.3)].
Inform patients that QSYMIA can cause confusion, concentration, and word-finding difficulties. Inform patients that the concomitant use of alcohol or central nervous system (CNS) depressant drugs with QSYMIA, may increase the risk of dizziness, cognitive adverse reactions, drowsiness, light-headedness, impaired coordination and somnolence.
Advise patients to tell their health care provider(s) about any changes in attention, concentration, memory, difficulty finding words, or other cognitive functions.
Advise patients not to drive or operate machinery until they have gained sufficient experience on QSYMIA to gauge whether it adversely affects their mental performance, motor performance, and/or vision. Advise patients to avoid excessive alcohol intake while taking QSYMIA [see Warnings and Precautions (5.5)].
Discuss with the patient and caregiver that long-term QSYMIA treatment may attenuate growth as reflected by slower height increase in pediatric patients [see Warnings and Precautions (5.6)].
Inform patients that QSYMIA can increase the risk of metabolic acidosis. Advise patients to tell their health care provider(s) about any factors that can increase the risk of acidosis (e.g. prolonged diarrhea, surgery, and high protein/low carbohydrate diet, and/or concomitant medications such as carbonic anhydrase inhibitors) [see Warnings and Precautions (5.7)].
Inform patients that abrupt withdrawal of topiramate has been associated with seizures in individuals without a history of seizures or epilepsy. Advise patients not to abruptly stop QSYMIA without first talking to their health care provider(s) [see Dosage and Administration (2.3) and Warnings and Precautions (5.9)].
Inform patients that use of QSYMIA has been associated with kidney stone formation. Advise patients to increase fluid intake to increase urinary output which can decrease the concentration of substances involved in kidney stone formation. Advise patients to report symptoms of severe side or back pain, and/or blood in their urine to their health care provider(s) [see Warnings and Precautions (5.10) and Adverse Reactions (6.1)].
Inform patients that oligohidrosis (decreased sweating) has been reported in association with the use of topiramate particularly in pediatric patients. Advise patients to monitor for decreased sweating and increased body temperature during physical activity, especially in hot weather [see Warnings and Precautions (5.11)].
Inform patients that serious skin reactions have been reported with use of topiramate. Inform patients of the signs of serious skin reactions and advise patients to report signs of a skin reaction to their health care provider(s) [see Warning and Precautions (5.13)].
Advise patients that breastfeeding is not recommended during QSYMIA treatment [see Use in Specific Populations (8.2)].
Inform patients that this product contains FD&C Yellow No. 5 (tartrazine) which may cause allergic-type reactions (including bronchial asthma) in certain susceptible persons [see Warnings and Precautions (5.14)].
Instruct patients on the dosage titration schedule of QSYMIA. Advise patients to take QSYMIA in the morning with or without food [see Dosage and Administration (2.2)].
In the event of a significant overdose with QSYMIA, if the ingestion is recent, the stomach should be emptied immediately by gastric lavage or by induction of emesis. Appropriate supportive treatment should be provided according to the patient’s clinical signs and symptoms. In the event of an overdose of QSYMIA, consider contacting the Poison Help line (1-800-222-1222) or a medical toxicologist for additional overdosage management recommendations.
Acute overdose of phentermine may be associated with restlessness, tremor, hyperreflexia, rapid respiration, confusion, aggressiveness, hallucinations, and panic states. Fatigue and depression usually follow the central stimulation. Cardiovascular effects include arrhythmia, hypertension or hypotension, and circulatory collapse. Gastrointestinal symptoms include nausea, vomiting, diarrhea, and abdominal cramps. Fatal poisoning usually terminates in convulsions and coma. Manifestations of chronic intoxication with anorectic drugs include severe dermatoses, marked insomnia, irritability, hyperactivity, and personality changes. A severe manifestation of chronic intoxication is psychosis, often clinically indistinguishable from schizophrenia.
Management of acute phentermine intoxication is largely symptomatic and includes lavage and sedation with a barbiturate. Acidification of the urine increases phentermine excretion. Intravenous phentolamine has been suggested for possible acute, severe hypertension, if this complicates phentermine overdosage.
Topiramate overdose has resulted in severe metabolic acidosis. Other signs and symptoms include convulsions, drowsiness, speech disturbance, blurred vision, diplopia, impaired mentation, lethargy, abnormal coordination, stupor, hypotension, abdominal pain, agitation, dizziness, and depression. The clinical consequences were not severe in most cases, but deaths have been reported after overdoses involving topiramate. A patient who ingested a dose between 96 and 110 gm topiramate was admitted to hospital with coma lasting 20 to 24 hours followed by full recovery after 3 to 4 days.
Hemodialysis is an effective means of removing topiramate from the body.
QSYMIA is contraindicated in patients:
Phentermine is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, amphetamine (d- and d/l-amphetamine). Drugs of this class used in obesity are commonly known as "anorectics" or "anorexigenics." The effect of phentermine on weight reduction and long-term maintenance of body weight is likely mediated by release of catecholamines in the hypothalamus, resulting in reduced appetite and decreased food consumption, but other metabolic effects may also be involved. The exact mechanism of action is not known.
The precise mechanism of action of topiramate on weight reduction and long-term maintenance of body weight is not known. Topiramate’s effect on weight reduction and long-term maintenance of body weight may be due to its effects on both appetite suppression and satiety enhancement, induced by a combination of pharmacologic effects including augmenting the activity of the neurotransmitter gamma-aminobutyrate, modulation of voltagegated ion channels, inhibition of AOBMPA/kainite excitatory glutamate receptors, or inhibition of carbonic anhydrase.
Typical actions of amphetamines include central nervous system stimulation and elevation of blood pressure. Tachyphylaxis and tolerance have been demonstrated with drugs in this class.
The effect of QSYMIA on the QTc interval was evaluated in a randomized, double-blind, placebo- and activecontrolled (400 mg moxifloxacin), and parallel group/crossover thorough QT/QTc study. A total of 54 healthy subjects were administered QSYMIA 7.5 mg/46 mg at steady state and then titrated to QSYMIA 22.5 mg/138 mg at steady state. QSYMIA 22.5 mg/138 mg [a supra-therapeutic dose resulting in a phentermine and topiramate maximum concentration (Cmax) of 4- and 3- times higher than those at QSYMIA 7.5 mg/46 mg, respectively] did not affect cardiac repolarization as measured by the change from baseline in QTc.
Healthy obese males and females received QSYMIA daily for 4 weeks (3.75 mg/23 mg on Days 1 to 3, 7.5 mg/46 mg on Days 4 to 6, 11.25 mg/69 mg on Days 7 to 9, and 15 mg/92 mg on Days 10 to 28). The glomerular filtration rate (GFR) of these participants was assessed via iohexol clearance. On average, GFR decreased during QSYMIA treatment and returned to baseline within 4 weeks after discontinuing QSYMIA [see Warnings and Precautions (5.8)]
The effect of QSYMIA on blood pressure as measured by 24-hr ABPM was evaluated in a randomized, doubleblind, 3-arm (QSYMIA, placebo, and active phentermine comparator) study of adults with obesity or overweight and at least one weight-related comorbidity. The study had a treatment duration of 8 weeks, and the primary endpoint was the change from baseline to Week 8 in mean systolic blood pressure (SBP) as measured by 24-hr ABPM.
QSYMIA 15 mg/92 mg did not demonstrate a pressor effect (see Table 6). At Week 8, placebo-adjusted mean (95% CI) treatment differences by 24-hr ABPM for QSYMIA 15 mg/92 mg were SBP -3.2 mmHg (-5.5, -0.9), DBP +1.2 mmHg (-0.2, +2.6), and heart rate (HR) +3.6 bpm (+2.1, +5.2). Placebo-adjusted mean weight loss was -3.9% (-4.9%, -3.0%) for QSYMIA 15 mg/92 mg and -3.8% (-4.7%, -2.9%) for phentermine 30 mg at Week 8.
Table 6. Ambulatory Blood Pressure Monitoring Results in Adults with Obesity or Overweight Treated with QSYMIA, Placebo, or Phentermine - Change from Baseline and Treatment Difference from Placebo and Phentermine at Week 8
|
APBM Measure |
Change from Baseline |
Treatment Difference |
||||
|
Placebo (n=130) |
QSYMIA 15 mg/ 92 mg |
Phentermine |
Qsymia – |
Qsymia - |
Phentermine - Placebo |
|
|
SBP (mmHg) |
-0.1 |
-3.3 |
+1.4 |
-3.2 |
-4.7 |
+1.5 |
|
DBP (mmHg) |
-0.4 |
+0.8 |
+2.4 |
+1.2 |
-1.5 |
+2.7 |
|
HR (bpm) Mean |
-1.0 |
+2.6 |
+6.2 |
+3.6 |
-3.6 |
+7.2 |
|
SBP=systolic blood pressure; DBP=diastolic blood pressure; HR=heart rate; BPM=beats per minute; ABPM=ambulatory blood pressure monitoring; CI=confidence interval An analysis of covariance (ANCOVA) model was used in the per protocol population (observed and single imputation data) to evaluate change from baseline and between-group differences. |
||||||
Phentermine
Upon oral administration of a single QSYMIA 15 mg/92 mg, the resulting mean plasma phentermine maximum concentration (Cmax), time to Cmax (Tmax), area under the concentration curve from time zero to the last time with measurable concentration (AUC0-t), and area under the concentration curve from time zero to infinity (AUC0-∞) are 49.1 ng/mL, 6 hr, 1990 ng⋅hr/mL, and 2000 ng⋅hr/mL, respectively. A high fat meal does not affect phentermine pharmacokinetics for QSYMIA 15 mg/92 mg. Phentermine pharmacokinetics are approximately dose-proportional from QSYMIA 3.75 mg/23 mg to phentermine 15 mg/topiramate 100 mg. Upon dosing phentermine 15 mg/topiramate 100 mg fixed dose combination capsule to steady state, the mean phentermine accumulation ratios for AUC and Cmax are both approximately 2.5.
Topiramate
Upon oral administration of a single QSYMIA 15 mg/92 mg, the resulting mean plasma topiramate Cmax, Tmax, AUC0-t, and AUC0-∞, are 1020 ng/mL, 9 hr, 61600 ng⋅hr/mL, and 68000 ng⋅hr/mL, respectively. A high fat meal does not affect topiramate pharmacokinetics for QSYMIA 15 mg/92 mg. Topiramate pharmacokinetics are approximately dose-proportional from QSYMIA 3.75 mg/23 mg to phentermine 15 mg/topiramate 100 mg. Upon dosing phentermine 15 mg/topiramate 100 mg fixed dose combination capsule to steady state, the mean topiramate accumulation ratios for AUC and Cmax are both approximately 4.0.
Phentermine
Phentermine is 17.5% plasma protein bound. The estimated phentermine apparent volume of distribution (Vd/F) is 348 L via population pharmacokinetic analysis.
Topiramate
Topiramate is 15 - 41% plasma protein bound over the blood concentration range of 0.5 to 250 µg/mL. The fraction bound decreased as blood topiramate increased. The estimated topiramate Vc/F (volume of the central compartment), and Vp/F (volume of the peripheral compartment) are 50.8 L, and 13.1 L, respectively, via population pharmacokinetic analysis.
Metabolism and Excretion
Phentermine
Phentermine has two metabolic pathways, namely p-hydroxylation on the aromatic ring and N-oxidation on the aliphatic side chain. Cytochrome P450 (CYP) 3A4 primarily metabolizes phentermine but does not show extensive metabolism. Monoamine oxidase (MAO)-A and MAO-B do not metabolize phentermine. Seventy to 80% of a dose exists as unchanged phentermine in urine when administered alone. The mean phentermine terminal half-life is about 20 hours. The estimated phentermine oral clearance (CL/F) is 8.79 L/h via population pharmacokinetic analysis.
Topiramate
Topiramate does not show extensive metabolism. Six topiramate metabolites (via hydroxylation, hydrolysis, and glucuronidation) exist, none of which constitutes more than 5% of an administered dose. About 70% of a dose exists as unchanged topiramate in urine when administered alone. The mean topiramate terminal half-life is about 65 hours. The estimated topiramate CL/F is 1.17 L/h via population pharmacokinetic analysis.
Patients with Renal Impairment
A single-dose, open-label study was conducted to evaluate the pharmacokinetics of QSYMIA 15 mg/92 mg in adult patients with varying degrees of chronic renal impairment compared to healthy volunteers with normal renal function. The study included patients with renal impairment classified on the basis of creatinine clearance as mild (greater or equal to 50 and less than 80 mL/min), moderate (greater than or equal to 30 and less than 50 mL/min), and severe (less than 30 mL/min). Creatinine clearance was estimated from serum creatinine based on the Cockcroft-Gault equation.
Compared to healthy volunteers, phentermine AUC0-inf was 91%, 45%, and 22% higher in patients with severe, moderate, and mild renal impairment, respectively; phentermine Cmax was 2% to 15% higher. Compared to healthy volunteers, topiramate AUC0-inf was 126%, 85%, and 25% higher for patients with severe, moderate, and mild renal impairment, respectively; topiramate Cmax was 6% to 17% higher. An inverse relationship between phentermine or topiramate Cmax or AUC and creatinine clearance was observed.
QSYMIA has not been studied in patients with end-stage renal disease on dialysis [see Dosage and Administration (2.4) and Use in Specific Populations (8.6)].
Patients with Hepatic Impairment
A single-dose, open-label study was conducted to evaluate the pharmacokinetics of QSYMIA 15 mg/92 mg in healthy volunteers with normal hepatic function compared with patients with mild (Child-Pugh score 5 - 6) and moderate (Child-Pugh score 7 - 9) hepatic impairment. In patients with mild and moderate hepatic impairment, phentermine AUC was 37% and 60% higher compared to healthy volunteers. Pharmacokinetics of topiramate was not affected in patients with mild and moderate hepatic impairment when compared with healthy volunteers. QSYMIA has not been studied in patients with severe hepatic impairment (Child-Pugh score 10 - 15) [see Dosage and Administration (2.5) and Use in Specific Populations (8.7)].
Pediatric Patients 12 to 17 years old
A randomized, double-blind, placebo-controlled study was conducted to evaluate the population pharmacokinetics of QSYMIA using data from 37 pediatric patients (12 to 17 years of age) with obesity. QSYMIA dosages of 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg were studied. QSYMIA exposure in the pediatric patients appeared comparable to that in adults.
In Vitro Assessment of Drug Interactions
Phentermine
Phentermine is not an inhibitor of CYP isozymes CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4, and is not an inhibitor of monoamine oxidases. Phentermine is not an inducer of CYP1A2, CYP2B6, and CYP3A4. Phentermine is not a P-glycoprotein substrate.
Topiramate
Topiramate is not an inhibitor of CYP isozymes CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4/5. However, topiramate is a mild inhibitor of CYP2C19. Topiramate is a mild inducer of CYP3A4. Topiramate is not a P-glycoprotein substrate.
Effects of Phentermine/Topiramate on Other Drugs
Table 7 describes the effect of phentermine/topiramate on the pharmacokinetics of co-administered drugs.
Table 7. Effect of Phentermine/Topiramate on the Pharmacokinetics of Co-administered Drugs
|
Phentermine/Topiramate |
Co-administered Drug and Dosing Regimen | ||
| Drug and Dose (mg) | Change in AUC | Change in Cmax | |
| *15 mg/92 mg dose QD for 16 days | Metformin 500 mg BID for 5 days | ↑ 23% | ↑ 16% |
| *15 mg/92 mg dose QD for 21 days | Sitagliptin 100 mg QD for 5 days | ↓ 3% | ↓ 9% |
| **15 mg/92 mg dose QD for 15 days | Oral contraceptive single dose norethindrone 1 mg ethinyl estradiol 35 mcg | ↑ 16% ↓16% |
↑ 22% |
| *A single study examined the effect of multiple-dose QSYMIA 15 mg/92 mg once daily on the pharmacokinetics of multipledose 500 mg metformin twice daily and multiple-dose 100 mg sitagliptin once daily in 10 males and 10 females (mean BMI of 27.1 kg/m2 and range of 22.2 – 32.7 kg/m2). The study participants received metformin, sitagliptin, phentermine/topiramate only, phentermine/topiramate plus probenecid, phentermine/topiramate plus metformin, and phentermine/topiramate plus sitagliptin on Days 1 – 5, 6 – 10, 11 – 28, 29, 30 – 34, and 35 – 39, respectively. The significance of these interactions is unknown. **See Drug Interactions (7) |
|||
Effect of Other Drugs on Phentermine/Topiramate
Table 8 describes the effect of other drugs on the pharmacokinetics of phentermine/topiramate.
Table 8. Effect of Co-administered Drugs on the Pharmacokinetics of Phentermine/Topiramate
|
Co-administered Drug and Dosing Regimen |
Phentermine/Topiramate |
||
|
Dose (mg) |
Change in AUC |
Change in Cmax |
|
|
Topiramate 92 mg single dose |
15 mg phentermine single dose |
↑ 42% |
↑ 13% |
|
Phentermine 15 mg single dose |
92 mg topiramate single dose |
↑ 6% |
↑ 2% |
|
*Metformin 500 mg BID for 5 days |
15 mg/92 mg dose QD for 16 days phentermine topiramate |
↑ 5% ↓ 5% |
↑ 7% ↓ 4% |
|
*Sitagliptin 100 mg QD for 5 days |
15 mg/92 mg dose QD for 21 days phentermine topiramate |
↑ 9% ↓ 2% |
↑ 10% ↓ 2% |
|
*Probenecid 2 g QD |
15 mg/92 mg dose QD for 11 days phentermine topiramate |
↓ 0.3% ↑ 0.7% |
↑ 4% ↑ 3% |
|
*The same single study examined the effect of multiple-dose 500 mg metformin twice daily, a single-dose 2 g probenecid, and multiple-dose 100 mg sitagliptin once daily on the pharmacokinetics of multiple-dose phentermine/topiramate 15 mg/92 mg once daily in 10 males and 10 females (mean BMI of 27.1 kg/m2 and range of 22.2 – 32.7 kg/m2). The study participants received metformin, sitagliptin, phentermine/topiramate only, phentermine/topiramate plus probenecid, phentermine/topiramate plus metformin, and phentermine/topiramate plus sitagliptin on Days 1 – 5, 6 – 10, 11 – 28, 29, 30 – 34, and 35 – 39, respectively. |
|||
Effects of Topiramate Alone on Other Drugs and Effects of Other Drugs on Topiramate Antiepileptic Drugs
Potential interactions between topiramate and standard antiepileptic (AED) drugs were assessed in controlled clinical pharmacokinetic studies in patients with epilepsy. The effects of these interactions on mean plasma AUCs are summarized in Table 9.
In Table 9, the second column (AED concentration) describes what happens to the concentration of the AED listed in the first column when topiramate is added. The third column (topiramate concentration) describes how the co-administration of a drug listed in the first column modifies the concentration of topiramate in experimental settings when topiramatewas given alone [see Drug Interactions (7)].
Table 9. Summary of AED Interactions with Topiramate
| AED Co-administered | AED Concentration | Topiramate Concentration |
| Phenytoin | NC or 25% increasea | 48% decrease |
| Carbamazepine (CBZ) | NC | 40% decrease |
| CBZ epoxideb | NC | NE |
| Valproic acid | 11% decrease | 14% decrease |
| Phenobarbital | NC | NE |
| Primidone | NC | NE |
| Lamotrigine | NC at TPM doses up to 400 mg/day | 13% decrease |
| a Plasma concentration increased 25% in some patients, generally those on a twice a day dosing regimen of phenytoin. b Is not administered but is an active metabolite of carbamazepine. NC = Less than 10% change in plasma concentration; NE = Not Evaluated; TPM = topiramate | ||
Digoxin
In a single-dose study, serum digoxin AUC was decreased by 12% with concomitant topiramate administration. The clinical relevance of this observation has not been established.
Hydrochlorothiazide
A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of hydrochlorothiazide (HCTZ) (25 mg q24h) and topiramate (96 mg q12h) when administered alone and concomitantly. The results of this study indicate that topiramate Cmax increased by 27% and AUC increased by 29% when HCTZ was added to topiramate. The clinical significance of this change is unknown. The steadystate pharmacokinetics of HCTZ were not significantly influenced by the concomitant administration of topiramate. Clinical laboratory results indicated decreases in serum potassium after topiramate or HCTZ administration,
which were greater when HCTZ and topiramate were administered in combination [see Drug Interactions (7) and Warnings and Precautions (5.12)].
Pioglitazone
A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of topiramate (96 mg twice daily) and pioglitazone (30 mg daily) when administered alone and concomitantly for
7 days. A 15% decrease in the area under the concentration-time curve during a dosage interval at steady state (AUCτ,ss) of pioglitazone with no alteration in maximum steady-state plasma drug concentration during a dosage interval (Cmax,ss) was observed. This finding was not statistically significant. In addition, a 13% and 16% decrease in Cmax,ss and AUCτ,ss respectively, of the active hydroxy-metabolite was noted as well as a 60% decrease in Cmax,ss and AUCτ,ss of the active keto-metabolite [see Drug Interactions (7)].
Glyburide
A drug-drug interaction study conducted in patients with type 2 diabetes mellitus evaluated the steady-state pharmacokinetics of glyburide (5 mg/day) alone and concomitantly with topiramate (150 mg/day). There was a 22% decrease in Cmax and a 25% reduction in AUC24 for glyburide during topiramate administration. Systemic exposure (AUC) of the active metabolites, 4-trans-hydroxyglyburide (M1), and 3-cis-hydroxyglyburide (M2), was reduced by 13% and 15%, and Cmax was reduced by 18% and 25%, respectively. The steady-state pharmacokinetics of topiramate were unaffected by concomitant administration of glyburide.
Lithium
In patients, the pharmacokinetics of lithium were unaffected during treatment with topiramate at doses of 200 mg/day; however, there was an observed increase in systemic exposure of lithium (27% for Cmax and 26% for AUC) following topiramate doses up to 600 mg/day.
Haloperidol
The pharmacokinetics of a single dose of haloperidol (5 mg) were not affected following multiple dosing of topiramate (100 mg every 12 hours) in 13 healthy adults (6 males, 7 females).
Amitriptyline
There was a 12% increase in AUC and Cmax for amitriptyline (25 mg per day) in 18 normal subjects (9 males, 9 females) receiving 200 mg/day of topiramate [see Drug Interactions (7)].
Sumatriptan
Multiple dosing of topiramate (100 mg every 12 hrs) in 24 healthy volunteers (14 males, 10 females) did not affect the pharmacokinetics of single-dose sumatriptan either orally (100 mg) or subcutaneously (6 mg).
Risperidone
When administered concomitantly with topiramate at escalating doses of 100, 250, and 400 mg/day, there was a reduction in risperidone systemic exposure (16% and 33% for steady-state AUC at the 250 and 400 mg/day doses of topiramate). No alterations of 9-hydroxyrisperidone levels were observed. Co-administration of topiramate 400 mg/day with risperidone resulted in a 14% increase in Cmax and a 12% increase in AUC12 of topiramate. There were no clinically significant changes in the systemic exposure of risperidone plus 9-hydroxyrisperidone or of topiramate; therefore, this interaction is not likely to be of clinical significance.
Propranolol
Multiple dosing of topiramate (200 mg/day) in 34 healthy volunteers (17 males, 17 females) did not affect the pharmacokinetics of propranolol following daily 160 mg doses. Propranolol doses of 160 mg/day in 39 volunteers (27 males, 12 females) had no effect on the exposure to topiramate, at a dose of 200 mg/day of topiramate.
Dihydroergotamine
Multiple dosing of topiramate (200 mg/day) in 24 healthy volunteers (12 males, 12 females) did not affect the pharmacokinetics of a 1 mg subcutaneous dose of dihydroergotamine. Similarly, a 1 mg subcutaneous dose of dihydroergotamine did not affect the pharmacokinetics of a 200 mg/day dose of topiramate in the same study.
Diltiazem
Co-administration of diltiazem hydrochloride extended-release with topiramate (150 mg/day) resulted in a 10% decrease in Cmax and a 25% decrease in diltiazem AUC, a 27% decrease in Cmax and an 18% decrease in desacetyl diltiazem AUC, and no effect on N-desmethyl diltiazem. Co-administration of topiramate with diltiazem hydrochloride extended-release resulted in a 16% increase in Cmax and a 19% increase in AUC12 of topiramate.
Venlafaxine
Multiple dosing of topiramate (150 mg/day) in healthy volunteers did not affect the pharmacokinetics of venlafaxine or O-desmethyl venlafaxine. Multiple dosing of venlafaxine (150 mg extended release) did not affect the pharmacokinetics of topiramate.
MEDICATION GUIDE
QSYMIA® (Kyoo sim ee uh)
(phentermine and topiramate extended-release capsules) for
oral use, CIV
What is the most important information I should know about QSYMIA?
QSYMIA can cause serious side effects, including:
Do not stop QYSMIA without first talking to a health care provider.
How can I watch for early symptoms of suicidal thoughts and actions?
QSYMIA can have other serious side effects. See “What are the possible side effects of QSYMIA?”
What is QSYMIA?
Who should not take QSYMIA? Do not take QSYMIA if you:
Before taking QSYMIA, tell your health care provider about all of your medical conditions, including if you:
Especially tell your health care provider if you take:
Ask your health care provider or pharmacist for a list of these medicines, if you are not sure.
Know the medicines you take. Keep a list of them to show your health care provider and pharmacist each time you get a new medicine. Do not start a new medicine without talking to your health care provider.
How should I take QSYMIA?
 |
If you take too much QSYMIA, call your health care provider or Poison Help line at 1-800-222-1222 or go to the nearest emergency room right away.
What should I avoid while taking QSYMIA?
What are the possible side effects of QSYMIA?
QSYMIA can cause serious side effects, including:
Your health care provider should do a blood test to measure the level of acid in your blood before and during your treatment with QSYMIA.
Common side effects of QSYMIA in adults include:
Common side effects of QSYMIA in children 12 years and older include:
Tell your health care provider if you have any side effect that bothers you or does not go away.
These are not all of the possible side effects of QSYMIA. For more information, ask your health care provider or pharmacist.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You can also report side effects to VIVUS at 1-888-998-4887.
How should I store QSYMIA?
Keep QSYMIA and all medicines out of the reach of children.
General Information about the safe and effective use of QSYMIA.
Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use QSYMIA for a condition for which it was not prescribed. Do not give QSYMIA to other people, even if they have the same symptoms you have. It may harm them.
You can ask your pharmacist or health care provider for information about QSYMIA that is written for health professionals.
What are the ingredients in QSYMIA?
Active Ingredient: phentermine hydrochloride and topiramate extended-release.
Inactive Ingredients: FD&C Blue #1, FD&C Red #3, FD&C Yellow #5 and #6, ethylcellulose, gelatin, methylcellulose, microcrystalline cellulose, povidone, starch, sucrose, talc, titanium dioxide, and pharmaceutical black and white inks.
Copyright © 2012 - 2023 VIVUS LLC All rights reserved.
VIVUS LLC
900 E. Hamilton Ave., Suite 550
Campbell, CA 95008 USA
 |
US Patent Numbers: 7,056,890; 7,553,818; 7,659,256; 7,674,776; 8,580,298; 8,580,299; 8,895,057; 8,895,058; 9,011,905; and 9,011,906.
QSYMIA is a registered trademark of VIVUS LLC.
This Medication Guide has been approved by the U.S. Food and Drug Administration.
