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WARNING
SEVERE NEUTROPENIA; ORTHOSTATIC HYPOTENSION, BRADYCARDIA, AND SYNCOPE; SEIZURE; MYOCARDITIS AND CARDIOMYOPATHY; INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS
CLOZARIL treatment has caused severe neutropenia, defined as an absolute neutrophil count (ANC) less than 500/μL. Severe neutropenia can lead to serious infection and death. Prior to initiating treatment with CLOZARIL a baseline ANC must be at least 1500/ μL for the general population; and must be at least 1000/μL for patients with documented Benign Ethnic Neutropenia (BEN). During treatment, patients must have regular ANC monitoring. Advise patients to immediately report symptoms consistent with severe neutropenia or infection (e.g., fever, weakness, lethargy, or sore throat) [see DOSAGE AND ADMINISTRATION and WARNINGS AND PRECAUTIONS].
Orthostatic hypotension, bradycardia, syncope, and cardiac arrest have occurred with CLOZARIL treatment. The risk is highest during the initial titration period, particularly with rapid dose escalation. These reactions can occur with the first dose, with doses as low as 12.5 mg per day. Initiate treatment at 12.5 mg once or twice daily; titrate slowly; and use divided dosages. Use CLOZARIL cautiously in patients with cardiovascular or cerebrovascular disease or conditions predisposing to hypotension (e.g., dehydration, use of antihypertensive medications) [see DOSAGE AND ADMINISTRATION and WARNINGS AND PRECAUTIONS].
Seizures have occurred with CLOZARIL treatment. The risk is dose-related. Initiate treatment at 12.5 mg, titrate gradually, and use divided dosing. Use caution when administering CLOZARIL to patients with a history of seizures or other predisposing risk factors for seizure (CNS pathology, medications that lower the seizure threshold, alcohol abuse). Caution patients about engaging in any activity where sudden loss of consciousness could cause serious risk to themselves or others [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS].
Fatal myocarditis and cardiomyopathy have occurred with CLOZARIL treatment. Discontinue CLOZARIL and obtain a cardiac evaluation upon suspicion of these reactions. Generally, patients with clozaril-related myocarditis or cardiomyopathy should not be rechallenged with CLOZARIL. Consider the possibility of myocarditis or cardiomyopathy if chest pain, tachycardia, palpitations, dyspnea, fever, flu-like symptoms, hypotension, or ECG changes occur [see WARNINGS AND PRECAUTIONS].
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. CLOZARIL is not approved for use in patients with dementia-related psychosis [see WARNINGS AND PRECAUTIONS].
CLOZARIL® (clozapine), an atypical antipsychotic drug, is a tricyclic dibenzodiazepine derivative, 8-chloro-11-(4-methyl-1-piperazinyl)-5H-dibenzo [b,e] [1,4] diazepine. The structural formula is
 |
CLOZARIL is available in pale yellow tablets of 25 mg and 100 mg for oral administration.
Active Ingredient: clozapine
Inactive Ingredients are colloidal silicon dioxide, lactose, magnesium stearate, povidone, starch (corn), and talc.
The following adverse reactions are discussed in more detail in other sections of 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 trials of another drug and may not reflect the rates observed in clinical practice.
The most commonly reported adverse reactions (>5%) across CLOZARIL clinical trials were: CNS reactions, including sedation, dizziness/vertigo, headache, and tremor; cardiovascular reactions, including tachycardia, hypotension, and syncope; autonomic nervous system reactions, including hypersalivation, sweating, dry mouth, and visual disturbances; gastrointestinal reactions, including constipation and nausea; and fever. Table 9 summarizes the most commonly reported adverse reactions (>5%) in CLOZARIL-treated patients (compared to chlorpromazine-treated patients) in the pivotal, 6-week, controlled trial in treatment-resistant schizophrenia.
Table 9. Common Adverse Reactions (≥5%) in the 6-Week, Randomized, Chlorpromazine-controlled Trial in Treatment-Resistant Schizophrenia
|
Adverse Reaction |
CLOZARIL |
Chlorpromazine |
| Sedation | 21 17 | 13 11 |
| Tachycardia | 16 14 | 12 16 |
| Constipation | 13 13 | 38 |
| Dizziness | 13 12 | 4 1 |
| Hypotension | 10 | 5 |
| Fever (hyperthermia) | 10 | 10 12 |
| Hypersalivation | 5 | 20 |
| Hypertension | ||
| Headache | ||
| Nausea/vomiting | ||
| Dry mouth |
Table 10 summarizes the adverse reactions reported in CLOZARIL-treated patients at a frequency of 2% or greater across all CLOZARIL studies (excluding the 2-year InterSePT™ Study). These rates are not adjusted for duration of exposure.
Table 10. Adverse Reactions (≥2%) Reported in CLOZARIL-treated Patients (N=842) Across all CLOZARIL Studies (excluding the 2-year InterSePT™ Study)
| Body System Adverse Reaction |
CLOZARIL N=842 Percentage of Patients |
|---|---|
| Central Nervous System | |
| Drowsiness/Sedation | 39 |
| Dizziness/Vertigo | 19 |
| Headache | 7 6 |
| Tremor | |
| Syncope | 6 |
| Disturbed Sleep/Nightmares | 4 |
| Restlessness | 4 4 |
| Hypokinesia/Akinesia | |
| Agitation | 4 |
| Seizures (convulsions) | 3† |
| Rigidity | 3 |
| Akathisia | 3 |
| Confusion | 3 |
| Fatigue | 2 |
| Insomnia | 2 |
| Cardiovascular | |
| Tachycardia | 25† |
| Hypotension | 9 |
| Hypertension | 4 |
| Gastrointestinal | |
| Constipation | 14 |
| Nausea | 5 |
| Abdominal Discomfort/Heartburn | 4 |
| Nausea/Vomiting | 3 |
| Vomiting | 3 |
| Diarrhea | 2 |
| Urogenital | |
| Urinary Abnormalities | 2 |
| Autonomic Nervous System | |
| Salivation | 31 |
| Sweating | 6 |
| Dry Mouth | 6 |
| Visual Disturbances | 5 |
| Skin | |
| Rash | 2 |
| Hemic/Lymphatic | |
| Leukopenia/Decreased WBC/Neutropenia | 3 |
| Miscellaneous | |
| Fever | 5 |
| Weight Gain | 4 |
| †Rate based on population of approximately 1700 exposed during premarket clinical evaluation of CLOZARIL. | |
Table 11 summarizes the most commonly reported adverse reactions (>10% of the CLOZARIL or olanzapine group) in the InterSePT™ Study. This was an adequate and well-controlled, two-year study evaluating the efficacy of CLOZARIL relative to olanzapine in reducing the risk of suicidal behavior in patients with schizophrenia or schizoaffective disorder. The rates are not adjusted for duration of exposure.
Table 11. Incidence of Adverse Reactions in Patients Treated with CLOZARIL or Olanzapine in the InterSePT™ Study (>10% in the CLOZARIL or olanzapine group)
| CLOZARIL | Olanzapine | |
| N=479 | N=477 | |
| Adverse Reactions | % Reporting | % Reporting |
| Salivary hypersecretion | 48 | 6 |
| Somnolence | 46 | 25 |
| Weight increased | 31 | 56 |
| Dizziness (excluding vertigo) | 27 | 12 |
| Constipation | 25 | 10 |
| Insomnia | 20 | 33 |
| Nausea | 17 | 10 |
| Vomiting | 17 | 9 |
| Dyspepsia | 14 | 8 |
Dystonia
Class effect: Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment. Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first generation antipsychotic drugs. An elevated risk of acute dystonia is observed in males and younger age groups.
The following adverse reactions have been identified during post-approval use of clozapine. 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.
Central Nervous System
Delirium, EEG abnormal, myoclonus, paresthesia, possible cataplexy, status epilepticus, obsessive compulsive symptoms, restless leg syndrome and post-discontinuation cholinergic rebound adverse reactions.
Cardiovascular System
Atrial or ventricular fibrillation, ventricular tachycardia, palpitations, QT interval prolongation, Torsades de Pointes, mitral valve incompetence associated with clozapine-related cardiomyopathy, myocardial infarction, cardiac arrest, myocarditis, pericarditis, and periorbital edema.
Endocrine System
Pseudopheochromocytoma
Gastrointestinal System
Acute pancreatitis, dysphagia, salivary gland swelling, colitis, megacolon, fecal incontinence, and intestinal ischemia, infarction, perforation, ulceration or necrosis.
Hepatobiliary System
Cholestasis, hepatitis, jaundice, hepatotoxicity, hepatic steatosis, hepatic necrosis, hepatic fibrosis, hepatic cirrhosis, liver injury (hepatic, cholestatic, and mixed), and liver failure.
Immune System Disorders
Angioedema, leukocytoclastic vasculitis.
Urogenital System
Acute interstitial nephritis, nocturnal enuresis, priapism, renal failure, and retrograde ejaculation.
Skin and Subcutaneous Tissue Disorders
Hypersensitivity reactions: photosensitivity, vasculitis, erythema multiforme, skin pigmentation disorder, and Stevens-Johnson Syndrome.
Musculoskeletal System and Connective Tissue Disorders
Myasthenic syndrome, rhabdomyolysis, and systemic lupus erythematosus.
Respiratory System
Aspiration, pleural effusion, pneumonia, lower respiratory tract infection, sleep apnea.
Hemic and Lymphatic System
Mild, moderate, or severe leukopenia, agranulocytosis, granulocytopenia, WBC decreased, deep-vein thrombosis, elevated hemoglobin/hematocrit, erythrocyte sedimentation rate (ESR) increased, sepsis, thrombocytosis, and thrombocytopenia.
Vision Disorders
Narrow-angle glaucoma.
Miscellaneous
Creatine phosphokinase elevation, hyperuricemia, hyponatremia, polyserositis, and weight loss.
Clozapine is a substrate for many cytochrome P450 isozymes, in particular CYP1A2, CYP3A4, and CYP2D6. Use caution when administering CLOZARIL concomitantly with drugs that are inducers or inhibitors of these enzymes.
CYP1A2 Inhibitors
Concomitant use of CLOZARIL and CYP1A2 inhibitors can increase plasma levels of clozapine, potentially resulting in adverse reactions. Reduce the CLOZARIL dose to one-third of the original dose when CLOZARIL is coadministered with strong CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin, or enoxacin). The CLOZARIL dose should be increased to the original dose when coadministration of strong CYP1A2 inhibitors is discontinued [see Dosage and Administration (2.7), Clinical Pharmacology (12.3)].
Moderate or weak CYP1A2 inhibitors include oral contraceptives and caffeine. Monitor patients closely when CLOZARIL is coadministered with these inhibitors. Consider reducing the CLOZARIL dosage if necessary [see Dosage and Administration (2.7)].
CYP2D6 and CYP3A4 Inhibitors
Concomitant treatment with CLOZARIL and CYP2D6 or CYP3A4 inhibitors (e.g., cimetidine, escitalopram, erythromycin, paroxetine, bupropion, fluoxetine, quinidine, duloxetine, terbinafine, or sertraline) can increase clozapine levels and lead to adverse reactions [see Clinical Pharmacology (12.3)]. Use caution and monitor patients closely when using such inhibitors. Consider reducing the CLOZARIL dose [see Dosage and Administration (2.7)].
CYP1A2 and CYP3A4 Inducers
Concomitant treatment with drugs that induce CYP1A2 or CYP3A4 can decrease the plasma concentration of clozapine, resulting in decreased effectiveness of CLOZARIL. Tobacco smoke is a moderate inducer of CYP1A2. Strong CYP3A4 inducers include carbamazepine, phenytoin, St. John’s wort, and rifampin. It may be necessary to increase the CLOZARIL dose if used concomitantly with inducers of these enzymes. However, concomitant use of CLOZARIL and strong CYP3A4 inducers is not recommended [see Dosage and Administration (2.7)].
Consider reducing the CLOZARIL dosage when discontinuing coadministered enzyme inducers; because discontinuation of inducers can result in increased clozapine plasma levels and an increased risk of adverse reactions [see Dosage and Administration (2.7)].
Anticholinergic Drugs
Concomitant treatment with clozapine and other drugs with anticholinergic activity (e.g., benztropine, cyclobenzaprine, diphenhydramine) can increase the risk for anticholinergic toxicity and severe gastrointestinal adverse reactions related to hypomotility. Avoid concomitant use of CLOZARIL with anticholinergic drugs when possible [see Warnings and Precautions (5.7, 5.15)].
Drugs that Cause QT Interval Prolongation
Use caution when administering concomitant medications that prolong the QT interval or inhibit the metabolism of clozapine. Drugs that cause QT prolongation include: specific antipsychotics (e.g., ziprasidone, iloperidone, chlorpromazine, thioridazine, mesoridazine, droperidol, and pimozide), specific antibiotics (e.g., erythromycin, gatifloxacin, moxifloxacin, sparfloxacin), Class 1A antiarrhythmics (e.g., quinidine, procainamide) or Class III antiarrhythmics (e.g., amiodarone, sotalol), and others (e.g., pentamidine, levomethadyl acetate, methadone, halofantrine, mefloquine, dolasetron mesylate, probucol or tacrolimus) [see Warnings and Precautions (5.9)].
Concomitant use of CLOZARIL with other drugs metabolized by CYP2D6 can increase levels of these CYP2D6 substrates. Use caution when coadministering CLOZARIL with other drugs that are metabolized by CYP2D6. It may be necessary to use lower doses of such drugs than usually prescribed. Such drugs include specific antidepressants, phenothiazines, carbamazepine, and Type 1C antiarrhythmics (e.g., propafenone, flecainide, and encainide).
Included as part of the PRECAUTIONS section.
CLOZARIL has caused severe neutropenia (absolute neutrophil count (ANC) less than 500/μL) [see Adverse Reactions (6.1, 6.2)] and is associated with an increased risk of serious and potentially fatal infections. Severe neutropenia occurred in a small percentage of CLOZARIL-treated patients. The risk of severe neutropenia appears greatest during the first 18 weeks of CLOZARIL treatment. The mechanism by which CLOZARIL causes neutropenia is unknown. Neutropenia is not dose dependent.
Consider a hematology consultation before initiating CLOZARIL treatment or during treatment.
ANC Monitoring and Dosage Modifications
Prior to initiating CLOZARIL treatment, obtain a baseline ANC. CLOZARIL initiation is not recommended in patients with a baseline ANC less than 1500/μL. Throughout CLOZARIL treatment, regularly monitor ANC. Table 1 provides recommendations for dosage modifications (dosage interruption and treatment discontinuation), based on ANC levels, during CLOZARIL treatment and frequency of ANC monitoring [see Dosage and Administration (2.3)].
ANC Monitoring and Dosage Modification in Patients with Benign Ethnic Neutropenia
Patients with Benign Ethnic Neutropenia (BEN) (also known as Duffy-null associated neutrophil count) generally have lower baseline neutrophil counts but they are not at higher risk for developing infections, and they are not at increased risk for developing CLOZARIL-induced neutropenia.
For patients with documented BEN, obtain at least two baseline ANC levels prior to CLOZARIL initiation. CLOZARIL initiation is not recommended in patients with BEN with an ANC less than 1000/μL. There are different ANC dosage modification recommendations in CLOZARIL-treated patients with BEN due to their lower baseline ANC levels. Table 2 provides recommendations on dosage modifications (dosage interruption and treatment discontinuation), based on ANC monitoring, during CLOZARIL treatment in patients with BEN and recommended frequency of ANC testing [see Dosage and Administration (2.4)].
Management of CLOZARIL-Treated Patients Who Develop a Fever
For patients who develop a fever during CLOZARIL treatment:
In patients with fever and a normal neutrophil count, see Warnings and Precautions (5.11) for neuroleptic malignant syndrome and Warnings and Precautions (5.13) for fever.
Restarting CLOZARIL in Patients Who Recovered from Severe Neutropenia
Generally, do not rechallenge patients with CLOZARIL in those who experienced severe neutropenia. However, for some patients who had resolution of their CLOZARIL-related severe neutropenia after stopping CLOZARIL, the risk of schizophrenia exacerbation from not restarting CLOZARIL treatment may be greater than the risk of neutropenia reoccurrence from restarting CLOZARIL (e.g., patients who have no treatment options other than CLOZARIL).
Concomitant Use of CLOZARIL with Other Drugs Known to Cause Neutropenia
If CLOZARIL is used concomitantly with another drug known to cause neutropenia, consider more frequently ANC monitoring than the recommendations provided in Table 1 and Table 2.
Hypotension, bradycardia, syncope, and cardiac arrest have occurred with clozapine treatment. The risk is highest during the initial titration period, particularly with rapid dose-escalation. These reactions can occur with the first dose, at doses as low as 12.5 mg. These reactions can be fatal. The syndrome is consistent with neurally mediated reflex bradycardia (NMRB).
Treatment must begin at a maximum dose of 12.5 mg once daily or twice daily. The total daily dose can be increased in increments of 25 mg to 50 mg per day, if well-tolerated, to a target dose of 300 mg to 450 mg per day (administered in divided doses) by the end of 2 weeks. Subsequently, the dose can be increased weekly or twice weekly, in increments of up to 100 mg. The maximum dose is 900 mg per day. Use cautious titration and a divided dosage schedule to minimize the risk of serious cardiovascular reactions [see Dosage and Administration (2.2)]. Consider reducing the dose if hypotension occurs. When restarting CLOZARIL in patients who have had even a brief interruption in treatment with CLOZARIL, the dosage must be reduced. This is necessary to minimize the risk of hypotension, bradycardia, and syncope [see Dosage and Administration (2.6)].
Use CLOZARIL cautiously in patients with cardiovascular disease (history of myocardial infarction or ischemia, heart failure, or conduction abnormalities), cerebrovascular disease, and conditions which would predispose patients to hypotension (e.g., concomitant use of antihypertensives, dehydration and hypovolemia).
CLOZARIL may cause somnolence, postural hypotension, motor and sensory instability, which may lead to falls and, consequently, fractures or other injuries. For patients with diseases, conditions, or medications that could exacerbate these effects, complete fall risk assessments when initiating antipsychotic treatment and recurrently for patients on long-term antipsychotic therapy.
Seizure has been estimated to occur in association with clozapine use at a cumulative incidence at one year of approximately 5%, based on the occurrence of one or more seizures in 61 of 1743 patients exposed to clozapine during its clinical testing prior to domestic marketing (i.e., a crude rate of 3.5%). The risk of seizure is dose-related. Initiate treatment with a low dose (12.5 mg), titrate slowly, and use divided dosing.
Use caution when administering CLOZARIL to patients with a history of seizures or other predisposing risk factors for seizure (e.g., head trauma or other CNS pathology, use of medications that lower the seizure threshold, or alcohol abuse). Because of the substantial risk of seizure associated with CLOZARIL use, caution patients about engaging in any activity where sudden loss of consciousness could cause serious risk to themselves or others (e.g., driving an automobile, operating complex machinery, swimming, climbing).
Myocarditis, pericarditis, and cardiomyopathy have occurred with the use of CLOZARIL. These reactions can be fatal.
Discontinue CLOZARIL and obtain a cardiac evaluation upon suspicion of myocarditis, pericarditis, or cardiomyopathy.
Generally, patients with a history of clozapine-associated myocarditis or cardiomyopathy should not be rechallenged with CLOZARIL. However, if the benefit of CLOZARIL treatment is judged to outweigh the potential risks of recurrence, the clinician may consider rechallenge with CLOZARIL in consultation with a cardiologist.
Myocarditis and pericarditis most frequently present within the first 2 months of clozapine treatment. Symptoms of cardiomyopathy generally occur later than clozapine-associated myocarditis or pericarditis and usually after 8 weeks of treatment. However, myocarditis, pericarditis, and cardiomyopathy can occur at any period during treatment with CLOZARIL. In patients who are diagnosed with cardiomyopathy while taking CLOZARIL mitral valve incompetence has been reported.
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Analyses of 17 placebo-controlled trials (modal duration of 10 weeks), largely in patients taking atypical antipsychotic drugs, revealed a risk of death in drug-treated patients of between 1.6 to 1.7 times the risk of death in placebo-treated patients. Over the course of a typical 10-week controlled trial, the rate of death in drug-treated patients was about 4.5%, compared to a rate of about 2.6% in the placebo group. Although the causes of death were varied, most of the deaths appeared to be either cardiovascular (e.g., heart failure, sudden death) or infectious (e.g., pneumonia) in nature.
Observational studies suggest that, similar to atypical antipsychotic drugs, treatment with conventional antipsychotic drugs may increase mortality in this population. The extent to which the findings of increased mortality in observational studies may be attributed to the antipsychotic drug as opposed to some characteristic(s) of the patients is not clear.
CLOZARIL is not approved for the treatment of patients with dementia-related psychosis [see Boxed Warning].
Severe gastrointestinal adverse reactions have occurred with the use of CLOZARIL, primarily due to its potent anticholinergic effects and resulting gastrointestinal hypomotility. In post marketing experience, reported effects range from constipation to paralytic ileus. Increased frequency of constipation and delayed diagnosis and treatment increased the risk of severe complications of gastrointestinal hypomotility, which can result in fecal impaction, megacolon, and intestinal obstruction, ischemia, infarction, perforation, ulceration, or necrosis [see Adverse Reaction (6.2)]. These reactions have resulted in hospitalization, surgery, and death. The risk of severe adverse reactions is further increased with anticholinergic medications (and other medications that decrease gastrointestinal peristalsis); therefore, concomitant use should be avoided when possible [see Warnings and Precautions (5.15), Drug Interactions (7.1)].
Prior to initiating CLOZARIL, screen for constipation and treat as necessary. Subjective symptoms of constipation may not accurately reflect the degree of gastrointestinal hypomotility in CLOZARIL treated patients. Therefore, reassess bowel function frequently with careful attention to any changes in the frequency or character of bowel movements, as well as signs and symptoms of complications of hypomotility (e.g., nausea, vomiting, abdominal distension, abdominal pain). If constipation or gastrointestinal hypomotility are identified, monitor closely and treat promptly with appropriate laxatives, as necessary, to prevent severe complications. Consider prophylactic laxatives in high risk patients.
Eosinophilia, defined as a blood eosinophil count of greater than 700/µL, has occurred with CLOZARIL treatment. In clinical trials, approximately 1% of patients developed eosinophilia. Clozapine-related eosinophilia usually occurs during the first month of treatment. In some patients, it has been associated with myocarditis, pancreatitis, hepatitis, colitis, and nephritis. Such organ involvement could be consistent with a drug reaction with eosinophilia and systemic symptoms syndrome (DRESS), also known as drug induced hypersensitivity syndrome (DIHS). If eosinophilia develops during CLOZARIL treatment, evaluate promptly for signs and symptoms of systemic reactions, such as rash or other allergic symptoms, myocarditis, or other organ-specific disease associated with eosinophilia. If CLOZARIL-related systemic disease is suspected, discontinue CLOZARIL immediately.
If a cause of eosinophilia unrelated to CLOZARIL is identified (e.g., asthma, allergies, collagen vascular disease, parasitic infections, and specific neoplasms), treat the underlying cause and continue CLOZARIL.
Clozapine-related eosinophilia has also occurred in the absence of organ involvement and can resolve without intervention. There are reports of successful rechallenge after discontinuation of clozapine, without recurrence of eosinophilia. In the absence of organ involvement, continue CLOZARIL under careful monitoring. If the total eosinophil count continues to increase over several weeks in the absence of systemic disease, the decision to interrupt CLOZARIL therapy and rechallenge after the eosinophil count decreases should be based on the overall clinical assessment, in consultation with an internist or hematologist.
QT prolongation, Torsade de Pointes and other life-threatening ventricular arrhythmias, cardiac arrest, and sudden death have occurred with CLOZARIL treatment. When prescribing CLOZARIL, consider the presence of additional risk factors for QT prolongation and serious cardiovascular reactions. Conditions that increase these risks include the following:
history of QT prolongation, long QT syndrome, family history of long QT syndrome or sudden cardiac death, significant cardiac arrhythmia, recent myocardial infarction, uncompensated heart failure, treatment with other medications that cause QT prolongation, treatment with medications that inhibit the metabolism of clozapine, and electrolyte abnormalities.
Prior to initiating treatment with CLOZARIL, perform a careful physical examination, medical history, and concomitant medication history. Consider obtaining a baseline ECG and serum chemistry panel. Correct electrolyte abnormalities. Discontinue CLOZARIL if the QTc interval exceeds 500 msec. If patients experience symptoms consistent with Torsades de Pointes, or other arrhythmias (e.g., syncope, presyncope, dizziness, or palpitations), obtain a cardiac evaluation and discontinue CLOZARIL.
Use caution when administering concomitant medications that prolong the QT interval or inhibit the metabolism of CLOZARIL. Drugs that cause QT prolongation include: specific antipsychotics (e.g., ziprasidone, iloperidone, chlorpromazine, thioridazine, mesoridazine, droperidol, pimozide), specific antibiotics (e.g., erythromycin, gatifloxacin, moxifloxacin, sparfloxacin), Class 1A antiarrhythmic medications (e.g., quinidine, procainamide) or Class III antiarrhythmics (e.g., amiodarone, sotalol), and others (e.g., pentamidine, levomethadyl acetate, methadone, halofantrine, mefloquine, dolasetron mesylate, probucol or tacrolimus). Clozapine is primarily metabolized by CYP isoenzymes 1A2, 2D6, and 3A4. Concomitant treatment with inhibitors of these enzymes can increase the concentration of CLOZARIL [see Drug Interactions (7.1) and Clinical Pharmacology (12.3)].
Hypokalemia and hypomagnesemia increase the risk of QT prolongation. Hypokalemia can result from diuretic therapy, diarrhea, and other causes. Use caution when treating patients at risk for significant electrolyte disturbance, particularly hypokalemia. Obtain baseline measurements of serum potassium and magnesium levels, and periodically monitor electrolytes. Correct electrolyte abnormalities before initiating treatment with CLOZARIL.
Atypical antipsychotic drugs, including CLOZARIL have been associated with metabolic changes that can increase cardiovascular and cerebrovascular risk. These metabolic changes include hyperglycemia, dyslipidemia, and body weight gain. While atypical antipsychotic drugs may produce some metabolic changes, each drug in the class has its own specific risk profile.
Hyperglycemia and Diabetes Mellitus
Hyperglycemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported in patients treated with atypical antipsychotics including CLOZARIL. Assessment of the relationship between atypical antipsychotic use and glucose abnormalities is complicated by the possibility of an increased background risk of diabetes mellitus in patients with schizophrenia and the increasing incidence of diabetes mellitus in the general population. Given these confounders, the relationship between atypical antipsychotic use and hyperglycemia-related adverse reactions is not completely understood. However, epidemiological studies suggest an increased risk of treatment-emergent, hyperglycemia-related adverse reactions in patients treated with the atypical antipsychotics. Precise risk estimates for hyperglycemia-related adverse reactions in patients treated with atypical antipsychotics are not available.
Patients with an established diagnosis of diabetes mellitus who are started on CLOZARIL should be monitored regularly for worsening of glucose control. Patients with risk factors for diabetes mellitus (e.g., obesity, family history of diabetes) who are starting treatment with atypical antipsychotics should undergo fasting blood glucose testing at the beginning of treatment and periodically during treatment. Any patient treated with atypical antipsychotics should be monitored for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Patients who develop symptoms of hyperglycemia during treatment with atypical antipsychotics should undergo fasting blood glucose testing. In some cases, hyperglycemia has resolved when the atypical antipsychotic was discontinued; however, some patients required continuation of antidiabetic treatment despite discontinuation of the suspect drug.
In a pooled data analysis of 8 studies in adult subjects with schizophrenia, the mean changes in fasting glucose concentration in the CLOZARIL and chlorpromazine groups were +11 mg/dL and +4 mg/dL respectively. A higher proportion of the CLOZARIL group demonstrated categorical increases from baseline in fasting glucose concentrations, compared to the chlorpromazine group (Table 4). The CLOZARIL doses were 100–900 mg per day (mean modal dose: 512 mg per day). The maximum chlorpromazine dose was 1800 mg per day (mean modal dose: 1029 mg per day). The median duration of exposure was 42 days for CLOZARIL and chlorpromazine.
Table 4. Categorical Changes in Fasting Glucose Level in Studies in Adult Subjects with Schizophrenia
| Laboratory Parameter | Category Change (at least once) from baseline | Treatment Arm | N | n (%) |
| Fasting Glucose | Normal (<100 mg/dL) to High (≥126 mg/dL) |
CLOZARIL | 198 | 53 (27) |
| Chlorpromazine | 135 | 14 (10) | ||
| Borderline (100 to 125 mg/dL) to High (≥126 mg/dL) |
CLOZARIL | 57 | 24 (42) | |
| Chlorpromazine | 43 | 12 (28) |
Dyslipidemia
Undesirable alterations in lipids have occurred in patients treated with atypical antipsychotics, including CLOZARIL. Clinical monitoring, including baseline and periodic follow-up lipid evaluations in patients using CLOZARIL, is recommended.
In a pooled data analysis of 10 studies in adult subjects with schizophrenia, CLOZARIL treatment was associated with increases in serum total cholesterol. No data were collected on LDL and HDL cholesterol. The mean increase in total cholesterol was 13 mg/dL in the CLOZARIL group and 15 mg/dL in the chlorpromazine group. In a pooled data analysis of 2 studies in adult subjects with schizophrenia, CLOZARIL treatment was associated with increases in fasting serum triglyceride. The mean increase in fasting triglyceride was 71 mg/dL (54%) in the CLOZARIL group and 39 mg/dL (35%) in the chlorpromazine group (Table 5). In addition, CLOZARIL treatment was associated with categorical increases in serum total cholesterol and triglyceride, as illustrated in Table 6. The proportion of patients with categorical increases in total cholesterol or fasting triglyceride increased with the duration of exposure. The median duration of CLOZARIL and chlorpromazine exposure was 45 days and 38 days, respectively. The CLOZARIL dose range was 100 mg to 900 mg daily; the maximum chlorpromazine dose was 1800 mg daily.
Table 5. Mean Changes in Total Cholesterol and Triglyceride Concentration in Studies in Adult Subjects with Schizophrenia
| Treatment Arm | Baseline total cholesterol concentration (mg/dL) | Change from baseline mg/dL (%) |
| CLOZARIL (N=334) | 184 | +13 (7) |
| Chlorpromazine (N=185) | 182 | +15 (8) |
| Baseline triglyceride concentration (mg/dL) | Change from baseline mg/dL (%) | |
| CLOZARIL (N=6) | 130 | +71 (54) |
| Chlorpromazine (N=7) | 110 | +39 (35) |
Table 6. Categorical Changes in Lipid Concentrations in Studies in Adult Subjects with Schizophrenia
| Laboratory Parameter | Category Change (at least once) from baseline | Treatment Arm | N | n (%) |
| Total Cholesterol (random or fasting) | Increase by ≥40 mg/dL | CLOZARIL | 334 | 111 (33) |
| Chlorpromazine | 185 | 46 (25) | ||
| Normal (<200 mg/dL) to High (≥240 mg/dL) |
CLOZARIL | 222 | 18 (8) | |
| Chlorpromazine | 132 | 3 (2) | ||
| Borderline (200 – 239 mg/dL) to High (≥240 mg/dL) |
CLOZARIL | 79 | 30 (38) | |
| Chlorpromazine | 34 | 14 (41) | ||
| Triglycerides (fasting) | Increase by ≥50 mg/dL | CLOZARIL | 6 | 3 (50) |
| Chlorpromazine | 7 | 3 (43) | ||
| Normal (<150 mg/dL) to High (≥200 mg/dL) |
CLOZARIL | 4 | 0 (0) | |
| Chlorpromazine | 6 | 2 (33) | ||
| Borderline (≥150 mg/dL and <200 mg/dL) to High (≥200 mg/dL) |
CLOZARIL | 1 | 1 (100) | |
| Chlorpromazine | 1 | 0 (0) | ||
Weight Gain
Weight gain has occurred with the use of antipsychotics, including CLOZARIL. Monitor weight during treatment with
CLOZARIL. Table 7 summarizes the data on weight gain by the duration of exposure pooled from 11 studies with CLOZARIL and active comparators. The median duration of exposure was 609, 728, and 42 days, in the CLOZARIL, olanzapine, and chlorpromazine group, respectively.
Table 7. Mean Change in Body Weight (kg) by Duration of Exposure from Studies in Adult Subjects with Schizophrenia
| Metabolic parameter | Exposure duration | CLOZARIL (N=669) |
Olanzapine (N=442) | Chlorpromazine (N=155) | |||
| n | Mean | n | Mean | n | Mean | ||
| Weight change from baseline | 2 weeks (Day 11–17) | 6 | +0.9 | 3 | +0.7 | 2 | -0.5 |
| 4 weeks (Day 21–35) | 23 | +0.7 | 8 | +0.8 | 17 | +0.6 | |
| 8 weeks (Day 49–63) | 12 | +1.9 | 13 | +1.8 | 16 | +0.9 | |
| 12 weeks (Day 70–98) | 17 | +2.8 | 5 | +3.1 | 0 | 0 | |
| 24 weeks (Day 154–182) | 42 | -0.6 | 12 | +5.7 | 0 | 0 | |
| 48 weeks (Day 322–350) | 3 | +3.7 | 3 | +13.7 | 0 | 0 | |
Table 8 summarizes pooled data from 11 studies in adult subjects with schizophrenia demonstrating weight gain ≥7% of body weight relative to baseline. The median duration of exposure was 609, 728, and 42 days, in the CLOZARIL, olanzapine, and chlorpromazine group, respectively.
Table 8. Proportion of Adult Subjects in Schizophrenia Studies with Weight Gain ≥7% Relative to Baseline Body Weight
|
Weight change |
CLOZARIL |
Olanzapine |
Chlorpromazine |
|
N |
669 |
442 |
155 |
|
≥7% (inclusive) |
236 (35%) |
203 (46%) |
13 (8%) |
Antipsychotic drugs including CLOZARIL can cause a potentially fatal symptom complex referred to as Neuroleptic Malignant Syndrome (NMS). Clinical manifestations of NMS include hyperpyrexia, muscle rigidity, altered mental status, and autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis, and cardiac dysrhythmias). Associated findings can include elevated creatine phosphokinase (CPK), myoglobinuria, rhabdomyolysis, and acute renal failure.
The diagnostic evaluation of patients with this syndrome is complicated. It is important to consider the presence of other serious medical conditions (e.g., severe neutropenia, infection, heat stroke, primary CNS pathology, central anticholinergic toxicity, extrapyramidal symptoms, and drug fever).
The management of NMS should include (1) immediate discontinuation of antipsychotic drugs and other drugs not essential to concurrent therapy, (2) intensive symptomatic treatment and medical monitoring, and (3) treatment of comorbid medical conditions. There is no general agreement about specific pharmacological treatments for NMS.
If a patient requires antipsychotic drug treatment after recovery from NMS, the potential reintroduction of drug therapy should be carefully considered. NMS can recur. Monitor closely if restarting treatment with antipsychotics.
NMS has occurred with CLOZARIL monotherapy and with concomitant CNS-active medications, including lithium.
Severe, life threatening, and in some cases fatal hepatotoxicity including hepatic failure, hepatic necrosis, and hepatitis have been reported in post marketing studies in patients treated with clozapine [see Adverse Reactions (6.2)]. Monitor for the appearance of signs and symptoms of hepatotoxicity such as fatigue, malaise, anorexia, nausea, jaundice, bilirubinemia, coagulopathy, and hepatic encephalopathy. Perform serum tests for liver injury and consider permanently discontinuing treatment if hepatitis or transaminase elevations combined with other systemic symptoms are due to clozapine.
During clozapine therapy, patients have experienced transient, clozapine-related fever. The peak incidence is within the first 3 weeks of treatment. While this fever is generally benign and self-limited, it may necessitate discontinuing treatment. The fever can be associated with an increase or decrease in WBC count. Carefully evaluate patients with fever to rule out severe neutropenia or infection. Consider the possibility of NMS [see Warnings and Precautions (5.11)].
Pulmonary embolism and deep-vein thrombosis have occurred in patients treated with CLOZARIL. Consider the possibility of pulmonary embolism in patients who present with deep-vein thrombosis, acute dyspnea, chest pain, or with other respiratory signs and symptoms. Whether pulmonary embolus and deep-vein thrombosis can be attributed to clozapine or some characteristic(s) of patients is not clear.
CLOZARIL has potent anticholinergic effects. Treatment with CLOZARIL can result in CNS and peripheral anticholinergic toxicity, especially at higher dosages, or in overdose situations [see Overdosage (10)]. Use with caution in patients with a current diagnosis or prior history of constipation, urinary retention, clinically significant prostatic hypertrophy, or other conditions in which anticholinergic effects can lead to significant adverse reactions. When possible, avoid concomitant use, with other anticholinergic medications because the risk for anticholinergic toxicity or severe gastrointestinal adverse reactions is increased [see Warnings and Precautions (5.7), Drug Interactions (7.1)].
CLOZARIL can cause sedation and impairment of cognitive and motor performance. Caution patients about operating hazardous machinery, including automobiles, until they are reasonably certain that CLOZARIL does not affect them adversely. These reactions may be dose-related. Consider reducing the dose if they occur.
Tardive dyskinesia (TD) has occurred in patients treated with antipsychotic drugs, including CLOZARIL. The syndrome consists of potentially irreversible, involuntary, dyskinetic movements. The risk of TD and the likelihood that it will become irreversible are believed to increase with greater durations of treatment and higher total cumulative doses. However, the syndrome can develop after relatively brief treatment periods at low doses. Prescribe CLOZARIL in a manner that is most likely to minimize the risk of developing TD. Use the lowest effective dose and the shortest duration necessary to control symptoms. Periodically assess the need for continued treatment. Consider discontinuing treatment if TD occurs. However, some patients may require treatment with CLOZARIL despite the presence of the syndrome.
TD may remit partially or completely if treatment is discontinued. Antipsychotic treatment, itself, may suppress (or partially suppress) the signs and symptoms, and it has the potential to mask the underlying process. The effect of symptom suppression on the long-term course of TD is unknown.
In controlled trials, elderly patients with dementia-related psychosis treated with some atypical antipsychotics had an increased risk (compared to placebo) of cerebrovascular adverse reactions (e.g., stroke, transient ischemic attack), including fatalities. The mechanism for this increased risk is not known. An increased risk cannot be excluded for CLOZARIL or other antipsychotics or other patient populations. CLOZARIL should be used with caution in patients with risk factors for cerebrovascular adverse reactions.
If abrupt discontinuation of CLOZARIL is necessary (because of severe neutropenia or another medical condition, for example) [see Dosage and Administration (2.5), Warnings and Precautions (5.1)], monitor carefully for the recurrence of psychotic symptoms and adverse reactions related to cholinergic rebound, such as profuse sweating, headache, nausea, vomiting and diarrhea.
Carcinogenesis
No carcinogenic potential was demonstrated in long-term studies in mice and rats at doses up to 0.3 times and 0.4 times, respectively, the maximum recommended human dose (MRHD) of 900 mg/day on a mg/m2 body surface area basis.
Mutagenesis
Clozapine was not genotoxic when tested in the following gene mutation and chromosomal aberration tests: the bacterial Ames test, the in vitro mammalian V79 in Chinese hamster cells, the in vitro unscheduled DNA synthesis in rat hepatocytes or the in vivo micronucleus assay in mice.
Impairment of Fertility
Clozapine had no effect on any parameters of fertility, pregnancy, fetal weight or postnatal development when administered orally to male rats 70 days before mating and to female rats for 14 days before mating at doses up to 0.4 times the MRHD of 900 mg/day on a mg/m2 body surface area basis.
The most commonly reported signs and symptoms associated with clozapine overdose are: sedation, delirium, coma, tachycardia, hypotension, respiratory depression or failure; and hypersalivation. There are reports of aspiration pneumonia, cardiac arrhythmias, and seizure. Fatal overdoses have been reported with clozapine, generally at doses above 2500 mg. There have also been reports of patients recovering from overdoses well in excess of 4 g.
There is no available specific antidote to an overdose of CLOZARIL. Establish and maintain an airway; ensure adequate oxygenation and ventilation. Monitor cardiac status and vital signs. Use general symptomatic and supportive measures. Consider the possibility of multiple-drug involvement.
Contact a Certified Poison Control Center for the most up to date information on the management of overdosage (1-800222-1222).
CLOZARIL is contraindicated in patients with a history of hypersensitivity to clozapine (e.g., photosensitivity, vasculitis, erythema multiforme, or Stevens-Johnson syndrome) or any other component of CLOZARIL [see Adverse Reactions (6.2)].
The mechanism of action of clozapine is unknown. However, it has been proposed that the therapeutic efficacy of clozapine in schizophrenia is mediated through antagonism of the dopamine type 2 (D2) and the serotonin type 2A (5-HT2A) receptors. CLOZARIL also acts as an antagonist at adrenergic, cholinergic, histaminergic and other dopaminergic and serotonergic receptors.
Clozapine demonstrated binding affinity to the following receptors: histamine H1 (Ki 1.1 nM), adrenergic α1A (Ki 1.6 nM), serotonin 5-HT6 (Ki 4 nM), serotonin 5-HT2A (Ki 5.4 nM), muscarinic M1 (Ki 6.2 nM), serotonin 5-HT7 (Ki 6.3 nM), serotonin 5-HT2C (Ki 9.4 nM), dopamine D4 (Ki 24 nM), adrenergic α2A (Ki 90 nM), serotonin 5-HT3 (Ki 95 nM), serotonin 5-HT1A (Ki 120 nM), dopamine D2 (Ki 160 nM), dopamine D1 (Ki 270 nM), dopamine D5 (Ki 454 nM), and dopamine D3 (Ki 555 nM).
Clozapine causes little or no prolactin elevation.
Clinical electroencephalogram (EEG) studies demonstrated that clozapine increases delta and theta activity and slows dominant alpha frequencies. Enhanced synchronization occurs. Sharp wave activity and spike and wave complexes may also develop. Patients have reported an intensification of dream activity during clozapine therapy. REM sleep was found to be increased to 85% of the total sleep time. In these patients, the onset of REM sleep occurred almost immediately after falling asleep.
Absorption
In humans, CLOZARIL tablets (25 mg and 100 mg) are equally bioavailable relative to a CLOZARIL solution. Following oral administration of CLOZARIL 100 mg twice daily, the average steady-state peak plasma concentration was 319 ng/mL (range: 102 to 771 ng/mL), occurring at the average of 2.5 hours (range: 1 to 6 hours) after dosing. The average minimum concentration at steady state was 122 ng/mL (range: 41 to 343 ng/mL), after 100 mg twice daily dosing. Food does not appear to affect the systemic bioavailability of CLOZARIL. Thus, CLOZARIL may be administered with or without food.
Clozapine is approximately 97% bound to serum proteins. The interaction between clozapine and other highly proteinbound drugs has not been fully evaluated but may be important [see Drug Interactions (7)].
Clozapine is almost completely metabolized prior to excretion, and only trace amounts of unchanged drug are detected in the urine and feces. Clozapine is a substrate for many cytochrome P450 isozymes, in particular CYP1A2, CYP2D6, and CYP3A4. Approximately 50% of the administered dose is excreted in the urine and 30% in the feces. The demethylated, hydroxylated, and N-oxide derivatives are components in both urine and feces. Pharmacological testing has shown the desmethyl metabolite (norclozapine) to have only limited activity, while the hydroxylated and N-oxide derivatives were inactive. The mean elimination half-life of clozapine after a single 75 mg dose was 8 hours (range: 4 to 12 hours), compared to a mean elimination half-life of 12 hours (range: 4 to 66 hours), after achieving steady state with 100 mg twice daily dosing.
A comparison of single-dose and multiple-dose administration of clozapine demonstrated that the elimination half-life increased significantly after multiple dosing relative to that after single-dose administration, suggesting the possibility of concentration-dependent pharmacokinetics. However, at steady state, approximately dose-proportional changes with respect to AUC (area under the curve), peak, and minimum clozapine plasma concentrations were observed after administration of 37.5, 75, and 150 mg twice daily.
Drug-Drug Interaction Studies
A pharmacokinetic study was conducted in 16 patients with schizophrenia who received clozapine under steady-state conditions. After coadministration of fluvoxamine for 14 days, mean trough concentrations of clozapine and its metabolites, N-desmethylclozapine and clozapine N-oxide, were elevated about three-fold compared to baseline steady-state concentrations.
In a study of patients with schizophrenia (n=14) who received clozapine under steady-state conditions, coadministration of paroxetine produced only minor changes in the levels of clozapine and its metabolites. However, other published reports describe modest elevations (less than two-fold) of clozapine and metabolite concentrations when clozapine was taken with paroxetine, fluoxetine, and sertraline.
Specific Population Studies
No specific pharmacokinetic studies were conducted to investigate the effects of renal or hepatic impairment on the pharmacokinetics of clozapine. Higher clozapine plasma concentrations are likely in patients with significant renal or hepatic impairment when given usual doses.
A subset (3%–10%) of the population has reduced activity of CYP2D6 (CYP2D6 poor metabolizers). These individuals may develop higher than expected plasma concentrations of clozapine when given usual doses.
Published case reports describe examples where pneumonia or other inflammatory conditions may increase clozapine concentrations. The clinical significance, the impact of treatments to modulate this inflammation, and mechanism of this potential increase in clozapine concentrations have not been fully characterized but may involve reduced cytochrome P450 1A2 activity.
Advise the patient to read the FDA-approved patient labeling (Medication Guide). Discuss the following issues with patients and caregivers:
Instruct patients (and caregivers) [see Warnings and Precautions (5.1)]:
− About the risk of developing severe neutropenia and infection with CLOZARIL treatment.
− Instruct patients to immediately report to their health care provider any symptom or sign of during CLOZARIL treatment.
− About the importance of having frequent ANC testing.
