Included as part of the "PRECAUTIONS" Section
Acute Myopia And Secondary Angle Closure Glaucoma
A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients receiving topiramate. Symptoms include acute onset of decreased visual acuity and/or ocular pain. Ophthalmologic findings can include myopia, anterior chamber shallowing, ocular hyperemia (redness) and increased intraocular pressure. Mydriasis may or may not be present. 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 topiramate 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 QUDEXY XR as rapidly as possible, according to the judgment of the treating physician. Other measures, in conjunction with discontinuation of QUDEXY XR, may be helpful.
Elevated intraocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent vision loss.
Visual Field Defects
Visual field defects (independent of elevated intraocular pressure) have been reported in patients receiving topiramate independent of elevated intraocular pressure. In clinical trials, most of these events were reversible after topiramate discontinuation. If visual problems occur at any time during treatment with topiramate, consideration should be given to discontinuing the drug.
Oligohydrosis And Hyperthermia
Oligohydrosis (decreased sweating), resulting in hospitalization in some cases, has been reported in association with topiramate use. Decreased sweating and an elevation in body temperature above normal characterized these cases. Some of the cases were reported after exposure to elevated environmental temperatures.
The majority of the reports have been in pediatric patients. Patients, especially pediatric patients, treated with QUDEXY XR should be monitored closely for evidence of decreased sweating and increased body temperature, especially in hot weather. Caution should be used when QUDEXY XR is prescribed with other drugs that predispose patients to heat-related disorders; these drugs include, but are not limited to, other carbonic anhydrase inhibitors and drugs with anticholinergic activity.
QUDEXY XR can cause hyperchloremic, non-anion gap, metabolic acidosis (i.e., decreased serum bicarbonate below the normal reference range in the absence of chronic respiratory alkalosis). This metabolic acidosis is caused by renal bicarbonate loss due to carbonic anhydrase inhibition by QUDEXY XR. QUDEXY XR-induced metabolic acidosis can occur at any time during treatment. Bicarbonate decrements are usually mild to moderate (average decrease of 4 mEq/L at daily doses of 400 mg in adults and at approximately 6 mg/kg/day in pediatric patients); rarely, patients can experience severe decrements to values below 10 mEq/L. Conditions or therapies that predispose patients to acidosis (such as renal disease, severe respiratory disorders, status epilepticus, diarrhea, ketogenic diet or specific drugs) may be additive to the bicarbonate lowering effects of QUDEXY XR.
Metabolic acidosis was commonly observed in adult and pediatric patients treated with immediate-release topiramate in clinical trials. The incidence of decreased serum bicarbonate in pediatric trials, for adjunctive treatment of Lennox-Gastaut syndrome or refractory partial-onset seizures was as high as 67% for immediate-release topiramate (at approximately 6 mg/kg/day), and 10% for placebo. The incidence of a markedly abnormally low serum bicarbonate (i.e., absolute value < 17 mEq/L and >5 mEq/L decrease from pretreatment) in these trials was up to 11%, compared to ≤ 2% for placebo.
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 [see Kidney Stones]. Chronic metabolic acidosis in pediatric patients may also reduce growth rates, which may decrease the maximal height achieved. The effect of topiramate on growth and bone-related sequelae has not been systematically investigated in long-term, placebo-controlled trials. Longterm, open-label treatment of pediatric patients 1 to 24 months old, with intractable partial epilepsy, for up to 1 year, showed reductions from baseline in length, weight, and head circumference compared to age and sex-matched normative data, although these patients with epilepsy are likely to have different growth rates than normal 1 to 24-month-old patients. Reductions in length and weight were correlated to the degree of acidosis [see Use In Specific Populations]. QUDEXY XR treatment that causes metabolic acidosis during pregnancy can possibly produce adverse effects on the fetus and might also cause metabolic acidosis in the neonate from possible transfer of topiramate to the fetus [see Fetal Toxicity, Use In Specific Populations].
Measurement Of Serum Bicarbonate In Epilepsy And Migraine Patients
Measurement of baseline and periodic serum bicarbonate during QUDEXY XR treatment is recommended. If metabolic acidosis develops and persists, consideration should be given to reducing the dose or discontinuing QUDEXY XR (using dose tapering). If the decision is made to continue patients on QUDEXY XR in the face of persistent acidosis, alkali treatment should be considered.
Suicidal Behavior And Ideation
Antiepileptic drugs (AEDs), including QUDEXY XR increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs 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. In these trials, which had a median treatment duration of 12 weeks, 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 drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.
The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one 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 (5 to 100 years) in the clinical trials analyzed.
Table 4 shows absolute and relative risk by indication for all evaluated AEDs.
Table 4: Risk by Indication for Antiepileptic Drugs in the Pooled Analysis
|Indication||Placebo Patients with Events per 1,000 Patients||Drug Patients with Events per 1,000 Patients||Relative Risk:|
Incidence of Events in Drug Patients/Incidence in Placebo Patients
Additional Drug Patients with Events per 1,000 Patients
The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
Anyone considering prescribing QUDEXY XR or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Cognitive/Neuropsychiatric Adverse Reactions
Immediate-release topiramate can cause cognitive/neuropsychiatric adverse reactions and therefore expected to be caused by QUDEXY XR. The most frequent of these can be classified into three general categories: 1) Cognitive-related dysfunction (e.g., confusion, psychomotor slowing, difficulty with concentration/attention, difficulty with memory, speech or language problems, particularly word-finding difficulties); 2) Psychiatric/behavioral disturbances (e.g., depression or mood problems); and 3) Somnolence or fatigue.
Cognitive Related Dysfunction
Rapid titration rate and higher initial dose were associated with higher incidences of cognitiverelated dysfunction.
In adult epilepsy adjunctive controlled trials, which used rapid titration (100 to 200 mg/day weekly increments) and target immediate-release topiramate doses of 200 mg to 1000 mg/day, 56% of patients in the 800 mg/day and 1000 mg/day dose groups experienced cognitive-related dysfunction compared to approximately 42% of patients in the 200 to 400 mg/day groups and 14% for placebo. In this rapid titration regimen, these dose-related adverse reactions began in the titration or in the maintenance phase, and in some patients these events began during titration and persisted into the maintenance phase.
In the monotherapy epilepsy-controlled trial conducted with immediate-release topiramate, the proportion of patients who experienced one or more cognitive-related adverse reactions was 19% for topiramate 50 mg per day and 26% for 400 mg per day.
In the 6-month controlled trials for the preventive treatment of migraine, which used a slower titration regimen (25 mg/day weekly increments), the proportion of patients who experienced one or more cognitive-related adverse reactions was 19% for topiramate 50 mg/day, 22% for 100 mg/day (the recommended dose), 28% for 200 mg/day, and 10% for placebo. Cognitive adverse reactions most commonly developed during titration and sometimes persisted after completion of titration.
Psychiatric/behavioral disturbances (e.g., depression or mood) were dose-related for both the adjunctive epilepsy and migraine populations treated with topiramate [see Suicidal Behavior And Ideation].
Somnolence and fatigue were the adverse reactions most frequently reported during clinical trials of topiramate for adjunctive epilepsy. For the adjunctive epilepsy population, the incidence of fatigue appeared dose-related. For the monotherapy epilepsy population, the incidence of somnolence was dose-related. For the migraine population, the incidences of both somnolence and fatigue were dose-related and more common in the titration phase.
In pediatric epilepsy trials (adjunctive and monotherapy), the incidence of cognitive/neuropsychiatric adverse reactions was generally lower than that observed in adults. These reactions included psychomotor slowing, difficulty with concentration/attention, speech disorders/related speech problems, and language problems. The most frequently reported cognitive/neuropsychiatric reactions in pediatric epilepsy patients during adjunctive therapy double-blind studies were somnolence and fatigue. The most frequently reported cognitive/neuropsychiatric reactions in pediatric epilepsy patients in the 50 mg/day and 400 mg/day groups during the monotherapy double-blind study were headache, dizziness, anorexia, and somnolence.
In pediatric migraine patients, the incidence of cognitive/neuropsychiatric adverse reactions was increased in topiramate-treated patients compared to placebo.
The risk for cognitive/neuropsychiatric adverse reactions was dose-dependent and was greatest at the highest dose (200 mg). This risk for cognitive/neuropsychiatric adverse reactions was also greater in younger patients (6 to 11 years of age) than in older patients (12 to 17 years of age). The most common cognitive/neuropsychiatric adverse reaction in these trials was difficulty with concentration/attention. Cognitive adverse reactions most commonly developed during the titration period and sometimes persisted for various durations after completion of titration.
The Cambridge Neuropsychological Test Automated Battery (CANTAB) was administered to adolescents (12 to 17 years of age) to assess the effects of topiramate on cognitive function at baseline and at the end of the Study 13 [see Clinical Studies]. Mean change from baseline in certain CANTAB tests suggests that topiramate treatment may result in psychomotor slowing and decreased verbal fluency.
QUDEXY XR can cause fetal harm when administered to a pregnant woman. Data from pregnancy registries indicate that infants exposed to topiramate in utero have an increased risk for cleft lip and/or cleft palate (oral clefts) and for being small for gestational age. When multiple species of pregnant animals received topiramate at clinically relevant doses, structural malformations, including craniofacial defects, and reduced fetal weights occurred in offspring [see Use In Specific Populations].
Consider the benefits and risks of QUDEXY XR when administering the drug in women of childbearing potential, particularly when QUDEXY XR is considered for a condition not usually associated with permanent injury or death [see Use In Specific Populations, PATIENT INFORMATION]. QUDEXY XR should be used during pregnancy only if the potential benefit outweighs the potential risk. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be informed of the potential hazard to a fetus [see Use In Specific Populations].
Withdrawal Of Antiepileptic Drugs
In patients with or without a history of seizures or epilepsy, antiepileptic drugs including QUDEXY XR, should be gradually withdrawn to minimize the potential for seizures or increased seizure frequency [see Clinical Studies]. In situations where, rapid withdrawal of QUDEXY XR is medically required, appropriate monitoring is recommended.
Hyperammonemia And Encephalopathy Without And With Concomitant Valproic Acid Use
Topiramate treatment can cause hyperammonemia with or without encephalopathy [see ADVERSE REACTIONS]. The risk for hyperammonemia with topiramate appears dose-related. Hyperammonemia has been reported more frequently when topiramate is used concomitantly with valproic acid. Post-marketing cases of hyperammonemia with or without encephalopathy have been reported with topiramate and valproic acid in patients who previously tolerated either drug alone [see DRUG INTERACTIONS].
Clinical symptoms of hyperammonemic encephalopathy often include acute alterations in level of consciousness and/or cognitive function with lethargy and/or vomiting. In most cases, hyperammonemic encephalopathy abated with discontinuation of treatment.
The incidence of hyperammonemia in pediatric patients 12 to 17 years of age in the preventive treatment of migraine trials was 26% in patients taking topiramate monotherapy at 100 mg/day, and 14% in patients taking topiramate at 50 mg/day, compared to 9% in patients taking placebo. There was also an increased incidence of markedly increased hyperammonemia at the 100 mg dose.
Dose-related hyperammonemia was also seen in pediatric patients 1 to 24 months of age treated with topiramate and concomitant valproic acid for partial-onset epilepsy and this was not due to a pharmacokinetic interaction.
In some patients, hyperammonemia can be asymptomatic.
Monitoring For Hyperammonemia
Patients with inborn errors of metabolism or reduced hepatic mitochondrial activity may be at an increased risk for hyperammonemia with or without encephalopathy. Although not studied, topiramate treatment or an interaction of concomitant topiramate and valproic acid treatment may exacerbate existing defects or unmask deficiencies in susceptible persons.
In patients who develop unexplained lethargy, vomiting, or changes in mental status associated with any topiramate treatment, hyperammonemic encephalopathy should be considered and an ammonia level should be measured.
Topiramate increases the risk of kidney stones. During adjunctive epilepsy trials, the risk for kidney stones in immediate-release topiramate-treated adults was 1.5%, an incidence about 2 to 4 times greater than expected in a similar, untreated population. As in the general population, the incidence of stone formation among topiramate-treated patients was higher in men. Kidney stones have also been reported in pediatric patients taking topiramate for epilepsy or migraine. During long-term (up to 1 year) topiramate treatment in an open-label extension study of 284 pediatric patients 1 to 24 months old with epilepsy, 7% developed kidney or bladder stones. QUDEXY XR is not approved for treatment of epilepsy in pediatric patients less than 2 years old [see Use In Specific Populations].
Topiramate is a carbonic anhydrase inhibitor. Carbonic anhydrase inhibitors can promote stone formation by reducing urinary citrate excretion and by increasing urinary pH [see Metabolic Acidosis]. The concomitant use of QUDEXY XR with any other drug producing metabolic acidosis, or potentially in patients on a ketogenic diet, may create a physiological environment that increases the risk of kidney stone formation, and should therefore be avoided.
Increased fluid intake increases the urinary output, lowering the concentration of substances involved in stone formation. Hydration is recommended to reduce new stone formation.
Hypothermia With Concomitant Valproic Acid Use
Hypothermia, defined as a drop-in body core temperature to <35°C (95°F), has been reported in association with topiramate use with concomitant valproic acid both in conjunction with hyperammonemia and in the absence of hyperammonemia. This adverse reaction in patients using concomitant topiramate and valproate can occur after starting topiramate treatment or after increasing the daily dose of topiramate [see DRUG INTERACTIONS]. Consideration should be given to stopping QUDEXY XR or valproate in patients who develop hypothermia, which may be manifested by a variety of clinical abnormalities including lethargy, confusion, coma, and significant alterations in other major organ systems such as the cardiovascular and respiratory systems. Clinical management and assessment should include examination of blood ammonia levels.
Carcinogenesis, Mutagenesis, Impairment Of Fertility
An increase in urinary bladder tumors was observed in mice given topiramate (0, 20, 75, and 300 mg/kg/day) in the diet for 21 months. An increase in the incidence of bladder tumors in males and females receiving 300 mg/kg/day was primarily due to the increased occurrence of a smooth muscle tumor considered histomorphologically unique to mice. The higher of the doses not associated with an increase in tumors (75 mg/kg/day) is equivalent to the maximum recommended human dose (MRHD) for epilepsy (400 mg) and approximately 4 times the MRHD for migraine (100 mg) on a mg/m2 basis. 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/day (approximately 3 times the MRHD for epilepsy and 12 times the MRHD for migraine on a mg/m2 basis).
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.
Impairment Of Fertility
No adverse effects on male or female fertility were observed in rats administrated topiramate orally at doses of up to 100 mg/kg/day (2.5 times the MRHD for epilepsy and 10 times the MRHD for migraine on a mg/m2 basis) prior to and during mating and early pregnancy.
Patient Counseling Information
Advise patients to read the FDA-approved patient labeling (Medication Guide).
Counsel patients to swallow QUDEXY XR capsules whole or carefully open and sprinkle the entire contents on a spoonful of soft food. This drug/food mixture should be swallowed immediately and not chewed. Do not store drug/food mixture for future use [see DOSAGE AND ADMINISTRATION].
Advise patients taking QUDEXY XR to seek immediate medical attention if they experience blurred vision, visual disturbances or periorbital pain [see WARNINGS AND PRECAUTIONS].
Oligohydrosis And Hyperthermia
Closely monitor QUDEXY XR-treated patients, especially pediatric patients, for evidence of decreased sweating and increased body temperature, especially in hot weather. Counsel patients to contact their healthcare professionals immediately if they develop a high or persistent fever, or decreased sweating [see WARNINGS AND PRECAUTIONS].
Warn patients about the potential significant risk for metabolic acidosis that may be asymptomatic and may be associated with adverse effects on kidneys (e.g., kidney stones, nephrocalcinosis), bones (e.g., osteoporosis, osteomalacia, and/or rickets in children), and growth (e.g., growth delay/retardation) in pediatric patients, and on the fetus [see WARNINGS AND PRECAUTIONS, Use In Specific Populations].
Suicidal Behavior And Ideation
Counsel patients, their caregivers, and families that AEDs, including QUDEXY XR, may increase the risk of suicidal thoughts and behavior and they should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior or the emergence of suicidal thoughts, behavior or thoughts about self-harm. Instruct patients to immediately report behaviors of concern to their healthcare providers [see WARNINGS AND PRECAUTIONS].
Interference With Cognitive And Motor Performance
Warn patients about the potential for somnolence, dizziness, confusion, difficulty concentrating, visual effects, and advise patients not to drive or operate machinery until they have gained sufficient experience on QUDEXY XR to gauge whether it adversely affects their mental performance, motor performance, and/or vision [see WARNINGS AND PRECAUTIONS].
Even when taking QUDEXY XR, or other anticonvulsants, some patients with epilepsy will continue to have unpredictable seizures. Therefore, advise all patients taking QUDEXY XR for epilepsy to exercise appropriate caution when engaging in any activities where loss of consciousness could result in serious danger to themselves or those around them (including swimming, driving a car, climbing in high places, etc.). Some patients with refractory epilepsy will need to avoid such activities altogether. Discuss the appropriate level of caution with patients, before patients with epilepsy engage in such activities.
Inform pregnant women and women of childbearing potential that use of QUDEXY XR during pregnancy can cause fetal harm, including an increased risk for cleft lip and/or cleft palate (oral clefts), which occur early in pregnancy before many women know they are pregnant. Also inform patients that infants exposed to topiramate monotherapy in utero may be small for their gestational age. There may also be risks to the fetus from chronic metabolic acidosis with use of QUDEXY XR during pregnancy [see WARNINGS AND PRECAUTIONS, Use In Specific Populations].
When appropriate, counsel pregnant women and women of childbearing potential about alternative therapeutic options. Advise women of childbearing potential who are not planning a pregnancy to use effective contraception while using QUDEXY XR, keeping in mind that there is a potential for decreased contraceptive efficacy when using estrogen-containing birth control with topiramate [see DRUG INTERACTIONS].
Encourage pregnant women using QUDEXY XR to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. The registry is collecting information about the safety of antiepileptic drugs during pregnancy [see Use In Specific Populations].
Hyperammonemia And Encephalopathy
Warn patients about the possible development of hyperammonemia with or without encephalopathy. Although hyperammonemia may be asymptomatic, clinical symptoms of hyperammonemic encephalopathy often include acute alterations in level of consciousness and/or cognitive function with lethargy and/or vomiting. This hyperammonemia and encephalopathy can develop with topiramate treatment alone or with topiramate treatment with concomitant valproic acid (VPA). Instruct patients to contact their physician if they develop unexplained lethargy, vomiting, or changes in mental status [see WARNINGS AND PRECAUTIONS].
Instruct patients, particularly those with predisposing factors, to maintain an adequate fluid intake in order to minimize the risk of kidney stone formation [see WARNINGS AND PRECAUTIONS].
Counsel patients that QUDEXY XR can cause a reduction in body temperature, which can lead to alterations in mental status. If they note such changes, they should call their health care professional and measure their body temperature. Patients taking concomitant valproic acid should be specifically counseled on this potential adverse reaction [see WARNINGS AND PRECAUTIONS].
Use In Specific Populations
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), such as QUDEXY XR, during pregnancy. Patients should be encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll-free number 1-888-233-2334. Information about the North American Drug Pregnancy Registry can be found at http://www.aedpregnancyregistry.org/.
QUDEXY XR can cause fetal harm when administered to a pregnant woman. Data from pregnancy registries indicate that infants exposed to topiramate in utero have increased risk for cleft lip and/or cleft palate (oral clefts) and for being small for gestational age (SGA) [see Human Data]. SGA has been observed at all doses and appears to be dose-dependent. The prevalence of SGA is greater in infants of women who received higher doses of topiramate during pregnancy. In addition, the prevalence of SGA in infants of women who continued topiramate use until later in pregnancy is higher compared to the prevalence in infants of women who stopped topiramate use before the third trimester.
In multiple animal species, topiramate demonstrated developmental toxicity, including increased incidences of fetal malformations, in the absence of maternal toxicity at clinically relevant doses [see Animal Data].
In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2% to 4% and 15% to 20%, respectively.
Fetal/Neonatal Adverse reactions
Consider the benefits and risks of topiramate when prescribing this drug to women of childbearing potential, particularlywhen topiramate is considered for a condition not usually associated with permanent injury or death. Because of the risk of oral clefts to the fetus, which occur in the first trimester of pregnancy before many women know they are pregnant, all women of childbearing potential should be informed of the potential risk to the fetus from exposure to topiramate.Women who are planning a pregnancy should be counseled regarding the relative risks and benefits of topiramate use during pregnancy, and alternative therapeutic options should be considered for these patients.
Labor or Delivery
Although the effect of topiramate on labor and delivery in humans has not been established, the development of topiramate-inducedmetabolic acidosis in the mother and/or in the fetus might affect the fetus’ ability to tolerate labor.
QUDEXY XR treatment can cause metabolic acidosis [see WARNINGS AND PRECAUTIONS]. The effect of topiramate-inducedmetabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) can cause decreased fetal growth, decreased fetal oxygenation, and fetal death, and may affect the fetus’ ability to tolerate labor. Pregnant patients should be monitored for metabolic acidosis and treated as in the nonpregnant state [see WARNINGS AND PRECAUTIONS]. Newborns of mothers treated with QUDEXY XR should be monitored for metabolic acidosis because of transfer of topiramate to the fetus and possible occurrence of transient metabolic acidosis following birth.
Based on limited information, topiramate has also been associated with pre-term labor and premature delivery.
Data from pregnancy registries indicate an increased risk of oral clefts in infants exposed to topiramate during the first trimester of pregnancy. In the NAAED pregnancy registry, the prevalence of oral clefts among topiramate-exposed infants (1.1%) was higher than the prevalence of infants exposed to a reference AED (0.36%) or the prevalence of infants of mothers without epilepsy and without exposure to AEDs (0.12%). It was also higher than the background prevalence in the United States (0.17%) as estimated by the Centers for Disease Control and Prevention (CDC). The relative risk of oral clefts in topiramate-exposed pregnancies in the NAAED Pregnancy Registry was 9.6 (95% Confidence Interval=[CI] 4.0 to 23.0) as compared to the risk in a background population of untreated women. The UK Epilepsy and Pregnancy Register reported a prevalence of oral clefts among infants exposed to topiramate monotherapy (3.2%) that was 16 times higher than the background rate in the UK (0.2%).
Data from the NAAED pregnancy registry and a population-based birth registry cohort indicate that exposure to topiramate in utero is associated with an increased risk of SGA newborns (birth weight <10th percentile). In the NAAED pregnancy registry, 19.7% of topiramate-exposed newborns were SGA compared to 7.9% of newborns exposed to a reference AED, and 5.4% of newborns of mothers without epilepsy and without AED exposure. In the Medical Birth Registry of Norway (MBRN), a population-based pregnancy registry, 25% of newborns in the topiramate monotherapy exposure group were SGA compared to 9% in the comparison group who were unexposed to AEDs. The long-term consequences of the SGA findings are not known.
When topiramate (0, 20, 100, or 500 mg/kg/day) was administered orally to pregnant mice during the period of organogenesis, the incidence of fetal malformations (primarily craniofacial defects) were increased at all doses. Fetal body weights and skeletal ossification were reduced at the highest dose tested in conjunction with decreased maternal body weight gain. A no-effect dose for embryofetal developmental toxicity in mice was not identified. The lowest dose tested, which was associated with an increased incidence of malformations, is less than the maximum recommended human dose (MRHD) for epilepsy (400 mg/day) or migraine (100 mg/day) on a body surface area (mg/m2) basis.
In pregnant rats administered topiramate (0, 20, 100, and 500 mg/kg/day or 0, 0.2, 2.5, 30, and 400 mg/kg/day) orally during the period of organogenesis, the frequency of limb malformations (ectrodactyly, micromelia, and amelia) was increased in fetuses at 400 and 500 mg/kg/day. Embryotoxicity (reduced fetal body weights, increased incidences of structural variations) was observed at doses as low as 20 mg/kg/day. Clinical signs of maternal toxicity were seen at 400 mg/kg/day and above, and maternal body weight gain was reduced at doses of 100 mg/kg/day or greater. The no-effect dose (2.5 mg/kg/day) for embryofetal developmental toxicity in rats is less than the MRHD for epilepsy or migraine on a mg/m2 basis.
In pregnant rabbits administered topiramate (0, 20, 60, and 180 mg/kg/day or 0, 10, 35, and 120 mg/kg/day) orally during organogenesis, embryofetal mortality was increased at 35 mg/kg/day and an increased incidence of fetal malformations (primarily rib and vertebral malformations) was observed at 120 mg/kg/day. Evidence of maternal toxicity (decreased body weight gain, clinical signs, and/or mortality) was seen at 35 mg/kg/day and above. The no-effect dose (20 mg/kg/day) for embryofetal developmental toxicity in rabbits is equivalent to the MRHD for epilepsy and approximately 4 times the MRHD for migraine on a mg/m2 basis.
When topiramate (0, 0.2, 4, 20, and 100 mg/kg/day or 0, 2, 20, and 200 mg/kg/day) was administered orally to female rats during the latter part of gestation and throughout lactation, offspring exhibited decreased viability and delayed physical development at 200 mg/kg/day and reductions in pre- and/or postweaning body weight gain at 2 mg/kg/day and above.Maternal toxicity (decreased body weight gain, clinical signs) was evident at 100 mg/kg/day or greater. In a rat embryofetal development study which included postnatal assessment of offspring, oral administration of topiramate (0, 0.2, 2.5, 30, and 400 mg/kg/day) to pregnant animals during the period of organogenesis resulted in delayed physical development in offspring at 400 mg/kg/day and persistent reductions in body weight gain in offspring at 30 mg/kg/day and higher. The noeffect dose (0.2 mg/kg/day) for pre- and postnatal developmental toxicity in rats is less than the MRHD for epilepsy or migraine on a mg/m2 basis.
Topiramate is excreted in human milk [see Data]. The effects of topiramate on milk production are unknown. Diarrhea and somnolence have been reported in breastfed infants whose mothers receive topiramate treatment.
The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for QUDEXY XR and any potential adverse effects on the breastfed infant from QUDEXY XR or from the underlying maternal condition.
Limited data from 5 women with epilepsy treated with topiramate during lactation showed drug levels in milk similar to those in maternal plasma.
Females And Males Of Reproductive Potential
Women of childbearing potential who are not planning a pregnancy should use effective contraception because of the risks to the fetus of oral clefts and of being small for gestational age [see DRUG INTERACTIONS and Pregnancy].
Seizures In Pediatric Patients 2 Years Of Age And Older
The safety and effectiveness of QUDEXY XR in pediatric patients is based on controlled trials with immediate-release topiramate [see Clinical Studies].
The adverse reactions (both common and serious) in pediatric patients are similar to those seen in adults [see WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS].
These include, but are not limited to:
- oligohydrosis and hyperthermia [see WARNINGS AND PRECAUTIONS]
- dose-related increased incidence of metabolic acidosis [see WARNINGS AND PRECAUTIONS]
- dose-related increased incidence of hyperammonemia [see WARNINGS AND PRECAUTIONS]
Adjunctive Treatment For Partial-Onset Epilepsy In Pediatric Patients 1 To 24 Months
The following pediatric use information is based on studies conducted with immediate-release topiramate.
Safety and effectiveness in patients below the age of 2 years have not been established for the adjunctive therapy treatment of partial-onset seizures, primary generalized tonic-clonic seizures, or seizures associated with Lennox-Gastaut syndrome. In a single randomized, double-blind, placebo-controlled investigational trial, the efficacy, safety, and tolerability of immediate-release topiramate oral liquid and sprinkle formulations as an adjunct to concurrent antiepileptic drug therapy in pediatric patients 1 to 24 months of age with refractory partial-onset seizures were assessed. After 20 days of double-blind treatment, immediate-release topiramate (at fixed doses of 5, 15, and 25 mg/kg/day) did not demonstrate efficacy compared with placebo in controlling seizures.
In general, the adverse reaction profile for immediate-release topiramate in this population was similar to that of older pediatric patients, although results from the above controlled study, and an open-label, long-term extension study in these pediatric patients 1 to 24 months old suggested some adverse reactions/toxicities not previously observed in older pediatric patients and adults; i.e., growth/length retardation, certain clinical laboratory abnormalities, and other adverse reactions that occurred with a greater frequency and/or greater severity than had been recognized previously from studies in older pediatric patients or adults for various indications.
These very young pediatric patients appeared to experience an increased risk for infections (any topiramate dose 12%, placebo 0%) and of respiratory disorders (any topiramate dose 40%, placebo 16%). The following adverse reactions were observed in at least 3% of patients on immediate-release topiramate and were 3% to 7% more frequent than in patients on placebo: viral infection, bronchitis, pharyngitis, rhinitis, otitis media, upper respiratory infection, cough, and bronchospasm. A generally similar profile was observed in older pediatric patients [see ADVERSE REACTIONS].
Immediate-release topiramate resulted in an increased incidence of patients with increased creatinine (any topiramate dose 5%, placebo 0%), BUN (any topiramate dose 3%, placebo 0%), and protein (any topiramate dose 34%, placebo 6%), and an increased incidence of decreased potassium (any topiramate dose 7%, placebo 0%). This increased frequency of abnormal values was not dose related. Creatinine was the only analyte showing a noteworthy increased incidence (topiramate 25 mg/kg/day 5%, placebo 0%) of a markedly abnormal increase [see ADVERSE REACTIONS]. The significance of these findings is uncertain.
Immediate-release topiramate treatment also produced a dose-related increase in the percentage of patients who had a shift from normal at baseline to high/increased (above the normal reference range) in total eosinophil count at the end of treatment. The incidence of these abnormal shifts was 6% for placebo, 10% for 5 mg/kg/day, 9% for 15 mg/kg/day, 14% for 25 mg/kg/day, and 11% for any topiramate dose [see ADVERSE REACTIONS]. There was a mean dose-related increase in alkaline phosphatase. The significance of these findings is uncertain.
Topiramate produced a dose-related increased incidence of hyperammonemia [see WARNINGS AND PRECAUTIONS].
Treatment with immediate-release topiramate for up to 1 year was associated with reductions in Z SCORES for length, weight, and head circumference [see WARNINGS AND PRECAUTIONS].
In open-label, uncontrolled experience, increasing impairment of adaptive behavior was documented in behavioral testing over time in this population. There was a suggestion that this effect was dose-related. However, because of the absence of an appropriate control group, it is not known if this decrement in function was treatment related or reflects the patient’s underlying disease (e.g., patients who received higher doses may have more severe underlying disease) [see WARNINGS AND PRECAUTIONS].
In this open-label, uncontrolled study, the mortality was 37 deaths/1000 patient years. It is not possible to know whether this mortality rate is related to immediate-release topiramate treatment, because the background mortality rate for a similar, significantly refractory, young pediatric population (1–24 months) with partial epilepsy is not known.
Monotherapy Treatment In Partial-Onset Epilepsy In Patients <2 Years Old
Safety and effectiveness in patients below the age of 2 years have not been established for the monotherapy treatment of epilepsy.
Preventive Treatment Of Migraine In Pediatric Patients 12 To 17 Years Of Age
Safety and effectiveness of topiramate for the preventive treatment of migraine was studied in 5 double-blind, randomized, placebo-controlled, parallel-group trials in a total of 219 pediatric patients, at doses of 50 to 200 mg/day, or 2 to 3 mg/kg/day. These comprised a fixed dose study in 103 pediatric patients 12 to 17 years of age [see Clinical Studies], a flexible dose (2 to 3 mg/kg/day), placebo-controlled study in 157 pediatric patients 6 to 16 years of age (including 67 pediatric patients 12 to 16 years of age), and a total of 49 pediatric patients 12 to 17 years of age in 3 studies for the preventive treatment of migraine primarily in adults. Open-label extension phases of 3 studies enabled evaluation of long-term safety for up to 6 months after the end of the double-blind phase.
Efficacy of topiramate for the preventive treatment of migraine in pediatric patients 12 to 17 years of age is demonstrated for a 100 mg daily dose in Study 3 [see Clinical Studies]. Efficacy of topiramate (2 to 3 mg/kg/day) for the preventive treatment of migraine was not demonstrated in a placebo-controlled trial of 157 pediatric patients (6 to 16 years of age) that included treatment of 67 pediatric patients 12 to 16 years of age for 20 weeks.
In the pediatric trials (12 to 17 years of age) in which patients were randomized to placebo or a fixed daily dose of immediate-release topiramate, the most common adverse reactions with immediate-release topiramate that were seen at an incidence higher (≥ 5%) than in the placebo group were: paresthesia, upper respiratory tract infection, anorexia, and abdominal pain [see ADVERSE REACTIONS].
The most common cognitive adverse reaction in pooled double-blind studies in pediatric patients 12 to 17 years of age was difficulty with concentration/attention [see WARNINGS AND PRECAUTIONS].
Markedly abnormally low serum bicarbonate values indicative of metabolic acidosis were reported in topiramate-treated pediatric migraine patients [see WARNINGS AND PRECAUTIONS].
In topiramate-treated pediatric patients (12 to 17 years of age) compared to placebo-treated patients, abnormally increased results were more frequent for creatinine, BUN, uric acid, chloride, ammonia, total protein, and platelets. Abnormally decreased results were observed with topiramate vs placebo treatment for phosphorus and bicarbonate [see WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS].
Notable changes (increases and decreases) from baseline in systolic blood pressure, diastolic blood pressure, and pulse that were observed occurred more commonly in pediatric patients treated with topiramate compared to pediatric patients treated with placebo [see CLINICAL PHARMACOLOGY].
Preventive Treatment Of Migraine In Pediatric Patients 6 To 11 Years Of Age
Safety and effectiveness in pediatric patients below the age of 12 years have not been established for the preventive treatment of migraine.
In a double-blind study in 90 pediatric patients 6 to 11 years of age (including 59 topiramatetreated and 31 placebo patients), the adverse reaction profile was generally similar to that seen in pooled double-blind studies of pediatric patients 12 to 17 years of age. The most common adverse reactions that occurred in immediate-release topiramate-treated pediatric patients 6 to 11 years of age, and at least twice as frequently than placebo, were gastroenteritis (12% topiramate, 6% placebo), sinusitis (10% topiramate, 3% placebo), weight loss (8% topiramate, 3% placebo) and paresthesia (7% topiramate, 0% placebo). Difficulty with concentration/attention occurred in 3 topiramate-treated patients (5%) and 0 placebo-treated patients.
The risk for cognitive adverse reaction was greater in younger patients (6 to 11 years of age) than in older patients (12 to 17 years of age) [see WARNINGS AND PRECAUTIONS].
Juvenile Animal Studies
When topiramate (0, 30, 90, or 300 mg/kg/day) was administered orally to rats during the juvenile period of development (postnatal days 12 to 50), bone growth plate thickness was reduced in males at the highest dose, which is approximately 5 to 8 times the maximum recommended pediatric dose (9 mg/kg/day) on a body surface area (mg/m2) basis.
Clinical studies of immediate-release topiramate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects. Dosage adjustment may be necessary for elderly with creatinine clearance less than 70 mL/min/1.73 m2. Estimate GFR should be measured prior to dosing [see DOSAGE AND ADMINISTRATION, in CLINICAL PHARMACOLOGY].
The clearance of topiramate is reduced in patients with moderate (creatinine clearance 30 to 69 mL/min/1.73 m2) and severe (creatinine clearance less than 30 mL/min/1.73 m2) renal impairment. A dosage adjustment is recommended in patients with moderate or severe renal impairment [see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY].
Patients Undergoing Hemodialysis
Topiramate is cleared by hemodialysis at a rate that is 4 to 6 times greater than in a normal individual. A dosage adjustment may be required [see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY].