Clozapine

Clozapine orally disintegrating tablets are indicated for the treatment of severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment. Because of the risks of severe neutropenia and of seizure associated with its use, clozapine orally disintegrating tablets should be used only in patients who have failed to respond adequately to standard antipsychotic treatment [see Warnings and Precautions ( 5.1, 5.5)] .

The effectiveness of clozapine in treatment-resistant schizophrenia was demonstrated in a 6-week, randomized, double-blind, active-controlled study comparing clozapine and chlorpromazine in patients who had failed other antipsychotics [see Clinical Studies (14.1)].

Clozapine orally disintegrating tablets are indicated for reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder who are judged to be at chronic risk for re-experiencing suicidal behavior, based on history and recent clinical state. Suicidal behavior refers to actions by a patient that put him/herself at risk for death.

The effectiveness of clozapine in reducing the risk of recurrent suicidal behavior was demonstrated over a two-year treatment period in the InterSePT™ trial [see Clinical Studies (14.2)] .

Prior to initiating treatment with clozapine orally disintegrating tablets, a baseline ANC must be obtained. The baseline ANC must be at least 1500/μL for the general population, and at least 1000/μL for patients with documented Benign Ethnic Neutropenia (BEN). To continue treatment, the ANC must be monitored regularly [see Warnings and Precautions (5.1)] .

Clozapine orally disintegrating tablets should be immediately placed in the mouth after removing the tablet from the blister pack or bottle. The tablet disintegrates rapidly after placement in the mouth. The tablets can be allowed to disintegrate, or they may be chewed. They may be swallowed with saliva. No water is necessary for administration.

The orally disintegrating tablets in a blister pack should be left in the unopened blister until the time of use. Just prior to use, peel the foil from the blister and gently remove the orally disintegrating tablet. Do not push the tablets through the foil, because this could damage the tablet.

The starting dose is 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 achieve 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 once weekly or twice weekly, in increments of up to 100 mg. The maximum dose is 900 mg per day. To minimize the risk of orthostatic hypotension, bradycardia, and syncope, it is necessary to use this low starting dose, gradual titration schedule, and divided dosages [see Warnings and Precautions (5.3)] .

Clozapine orally disintegrating tablets can be taken with or without food [see Pharmacokinetics (12.3)] .

Generally, patients responding to clozapine orally disintegrating tablets should continue maintenance treatment on their effective dose beyond the acute episode.

Method of treatment discontinuation will vary depending on the patient’s last ANC:

• See Tables 2 or 3 for appropriate ANC monitoring based on the level of neutropenia if abrupt treatment discontinuation is necessary because of moderate to severe neutropenia.
• Reduce the dose gradually over a period of 1 to 2 weeks if termination of clozapine orally disintegrating tablets therapy is planned and there is no evidence of moderate to severe neutropenia.
• For abrupt clozapine discontinuation for a reason unrelated to neutropenia, continuation of the existing ANC monitoring is recommended for general population patients until their ANC is ≥ 1500/μL and for BEN patients until their ANC is ≥ 1000/μL or above their baseline.
• Additional ANC monitoring is required for any patient reporting onset of fever (temperature of 38.5°C or 101.3°F, or greater) during the 2 weeks after discontinuation [see Warnings and Precautions (5.1)] .
• Monitor all patients carefully for the recurrence of psychotic symptoms and symptoms related to cholinergic rebound such as profuse sweating, headache, nausea, vomiting, and diarrhea.

When restarting clozapine orally disintegrating tablets in patients who have had even a brief interruption in treatment with clozapine orally disintegrating tablets, dosage must be reduced. This is necessary to minimize the risk of hypotension, bradycardia, and syncope [see Warnings and Precautions (5.3)] . If one day’s dosing has been missed, resume treatment at 40% to 50% of the established dose. If two days dosing has been missed, resume dosage at approximately 25% of the established dosage. For longer interruptions, re-initiate with a dosage of 12.5 mg once daily or twice daily. If these dosages are well tolerated, the dosage may be increased to the previous dosage more quickly than recommended for initial treatment.

Dose adjustments may be necessary in patients with concomitant use of: strong CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin, or enoxacin); moderate or weak CYP1A2 inhibitors (e.g., oral contraceptives, or caffeine); CYP2D6 or CYP3A4 inhibitors (e.g., cimetidine, escitalopram, erythromycin, paroxetine, bupropion, fluoxetine, quinidine, duloxetine, terbinafine, or sertraline); CYP3A4 inducers (e.g., phenytoin, carbamazepine, St. John’s wort, and rifampin); or CYP1A2 inducers (e.g., tobacco smoking) (Table 1) [see Drug Interactions (7)] .

It may be necessary to reduce the clozapine orally disintegrating tablets dose in patients with significant renal or hepatic impairment, or in CYP2D6 poor metabolizers [see Use in Specific Populations (8.6, 8.7)] .

Clozapine orally disintegrating tablets are only available through a restricted program under a REMS called the Clozapine REMS Program because of the risk of severe neutropenia.

Notable requirements of the Clozapine REMS Program include:

• Healthcare professionals who prescribe clozapine orally disintegrating tablets must be certified with the program by enrolling and completing training.
• Patients who receive clozapine orally disintegrating tablets must be enrolled in the program and comply with the ANC testing and monitoring requirements.
• Pharmacies dispensing clozapine orally disintegrating tablets must be certified with the program by enrolling and completing training and must only dispense to patients who are eligible to receive clozapine orally disintegrating tablets.

Further information is available at www.clozapinerems.com or 1-844-267-8678.

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 (2.3)] . Consider reducing the dose if hypotension occurs. When restarting clozapine orally disintegrating tablets in patients who have had even a brief interruption in treatment with clozapine orally disintegrating tablets, the dosage must be reduced. This is necessary to minimize the risk of hypotension, bradycardia, and syncope [see Dosage and Administration (2.6)] .

Use clozapine orally disintegrating tablets 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).

Clozapine orally disintegrating tablets may cause somnolence, postural hypotension, and 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 treatment.

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 clozapine orally disintegrating tablets 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 clozapine orally disintegrating tablets 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 clozapine orally disintegrating tablets. These reactions can be fatal. Discontinue clozapine orally disintegrating tablets and obtain a cardiac evaluation upon suspicion of myocarditis, pericarditis, or cardiomyopathy. Generally, patients with a history of clozapine-associated myocarditis, pericarditis, or cardiomyopathy should not be rechallenged with clozapine orally disintegrating tablets. However, if the benefit of clozapine orally disintegrating tablets treatment is judged to outweigh the potential risks of recurrence, the clinician may consider rechallenge with clozapine orally disintegrating tablets in consultation with a cardiologist.

Consider the possibility of myocarditis or cardiomyopathy in patients receiving clozapine orally disintegrating tablets who present with chest pain, dyspnea, persistent tachycardia at rest, palpitations, fever, flu-like symptoms, hypotension, other signs or symptoms of heart failure, or electrocardiographic findings (low voltages, ST-T abnormalities, arrhythmias, right axis deviation, and poor R wave progression). Myocarditis and pericarditis most frequently present within the first 2 months of clozapine treatment. Symptoms of cardiomyopathy generally occur later than clozapine-associated myocarditis and usually after 8 weeks of treatment. However, myocarditis, pericarditis, and cardiomyopathy can occur at any period during treatment with clozapine orally disintegrating tablets. In patients who are diagnosed with cardiomyopathy while taking clozapine orally disintegrating tablets, 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. Clozapine orally disintegrating tablets are not approved for the treatment of patients with dementia-related psychosis [see Boxed Warning] .

Severe gastrointestinal adverse reactions have occurred with the use of clozapine orally disintegrating tablets, 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 for 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 (5.16)and Drug Interactions (7.1)] .

Prior to initiating clozapine orally disintegrating tablets, screen for constipation and treat as necessary. Subjective symptoms of constipation may not accurately reflect the degree of gastrointestinal hypomotility in clozapine orally disintegrating tablets 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 clozapine 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 clozapine orally disintegrating tablets 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 clozapine-related systemic disease is suspected, discontinue clozapine orally disintegrating tablets immediately.

If a cause of eosinophilia unrelated to clozapine is identified (e.g., asthma, allergies, collagen vascular disease, parasitic infections, and specific neoplasms), treat the underlying cause and continue clozapine orally disintegrating tablets.

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 clozapine orally disintegrating tablets under careful monitoring. If the total eosinophil count continues to increase over several weeks in the absence of systemic disease, the decision to interrupt clozapine orally disintegrating tablets 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, Torsades de Pointes and other life-threatening ventricular arrhythmias, cardiac arrest, and sudden death have occurred with clozapine treatment. When prescribing clozapine orally disintegrating tablets, 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 orally disintegrating tablets, and electrolyte abnormalities.

Prior to initiating treatment with clozapine orally disintegrating tablets, perform a careful physical examination, medical history, and concomitant medication history. Consider obtaining a baseline ECG and serum chemistry panel. Correct electrolyte abnormalities. Discontinue clozapine orally disintegrating tablets 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 clozapine orally disintegrating tablets.

Use caution when administering concomitant medications that prolong the QT interval or inhibit the metabolism of clozapine orally disintegrating tablets. 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 orally disintegrating tablets are primarily metabolized by CYP isoenzymes 1A2, 2D6, and 3A4. Concomitant treatment with inhibitors of these enzymes can increase the concentration of clozapine orally disintegrating tablets [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 clozapine orally disintegrating tablets.

Atypical antipsychotic drugs, including clozapine orally disintegrating tablets, 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.

Antipsychotic drugs including clozapine orally disintegrating tablets 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 co-morbid 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 clozapine 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 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 clozapine. 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.

Clozapine orally disintegrating tablets have potent anticholinergic effects. Treatment with clozapine orally disintegrating tablets 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 (5.8)and Drug Interactions (7.1) ].

Clozapine orally disintegrating tablets can cause sedation and impairment of cognitive and motor performance. Caution patients about operating hazardous machinery, including automobiles, until they are reasonably certain that clozapine orally disintegrating tablets do 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 clozapine orally disintegrating tablets. 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 clozapine orally disintegrating tablets 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 clozapine orally disintegrating tablets despite the presence of the syndrome.

There is no known treatment for TD. However, the syndrome 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.

Phenylketonuric patients should be informed that clozapine orally disintegrating tablets contain phenylalanine (a component of aspartame). Each 25 mg, orally disintegrating tablet contains 1.90 mg phenylalanine. Each 100 mg, orally disintegrating tablet contains 7.59 mg phenylalanine. Each 150 mg, orally disintegrating tablet contains 11.38 mg phenylalanine. Each 200 mg, orally disintegrating tablet contains 15.18 mg phenylalanine.

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 clozapine orally disintegrating tablets or other antipsychotics or other patient populations. Clozapine orally disintegrating tablets should be used with caution in patients with risk factors for cerebrovascular adverse reactions.

If abrupt discontinuation of clozapine orally disintegrating tablets is necessary (because of severe neutropenia or another medical condition, for example) [see Dosage and Administration (2.5)and 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.

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 clozapine 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 clozapine-treated patients (compared to chlorpromazine-treated patients) in the pivotal, 6-week, controlled trial in treatment-resistant schizophrenia.

Table 10 summarizes the adverse reactions reported in clozapine-treated patients at a frequency of 2% or greater across all clozapine studies (excluding the 2-year InterSePT™ Study). These rates are not adjusted for duration of exposure.

Table 11 summarizes the most commonly reported adverse reactions (≥ 10% of the clozapine or olanzapine group) in the InterSePT™ Study. This was an adequate and well-controlled, two-year study evaluating the efficacy of clozapine 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.

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, and post-discontinuation cholinergic rebound adverse reactions.

Cardiovascular System:Atrial or ventricular fibrillation, ventricular tachycardia, QT interval prolongation, Torsades de Pointes, myocardial infarction, cardiac arrest, pericarditis, and periorbital edema.

Endocrine System:Pseudopheochromocytoma.

Gastrointestinal System:Acute pancreatitis, dysphagia, salivary gland swelling, 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, and renal failure.

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.

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, and weight loss.

Clozapine is a substrate for many cytochrome P450 isozymes, in particular CYP1A2, CYP3A4, and CYP2D6. Use caution when administering clozapine orally disintegrating tablets concomitantly with drugs that are inducers or inhibitors of these enzymes.

Concomitant use of clozapine orally disintegrating tablets with other drugs metabolized by CYP2D6 can increase levels of these CYP2D6 substrates. Use caution when coadministering clozapine orally disintegrating tablets 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).

Clozapine is present in human milk. Because of the potential for serious adverse reactions in nursing infants from clozapine orally disintegrating tablets, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Safety and effectiveness in pediatric patients have not been established.

There have not been sufficient numbers of geriatric patients in clinical studies utilizing clozapine orally disintegrating tablets to determine whether those over 65 years of age differ from younger subjects in their response to clozapine orally disintegrating tablets.

Orthostatic hypotension and tachycardia can occur with clozapine treatment [see Boxed Warningand Warnings and Precautions (5.3)] . Elderly patients, particularly those with compromised cardiovascular functioning, may be more susceptible to these effects.

Elderly patients may be particularly susceptible to the anticholinergic effects of clozapine, such as urinary retention and constipation [see Warnings and Precautions (5.16)] .

Carefully select clozapine orally disintegrating tablets doses in elderly patients, taking into consideration their greater frequency of decreased hepatic, renal, or cardiac function, as well as other concomitant disease and other drug therapy. Clinical experience suggests that the prevalence of tardive dyskinesia appears to be highest among the elderly; especially elderly women [see Warnings and Precautions (5.18)] .

Dose reduction may be necessary in patients with significant impairment of renal or hepatic function. Clozapine concentrations may be increased in these patients, because clozapine is almost completely metabolized and then excreted [see Dosage and Administration (2.8)and Clinical Pharmacology (12.3)] .

Dose reduction may be necessary in patients who are CYP2D6 poor metabolizers. Clozapine concentrations may be increased in these patients, because clozapine is almost completely metabolized and then excreted [see Dosage and Administration (2.8)and Clinical Pharmacology (12.3)] .

For hospice patients (i.e., terminally ill patients with an estimated life expectancy of 6 months or less), the prescriber may reduce the ANC monitoring frequency to once every 6 months, after a discussion with the patient and his/her caregiver. Individual treatment decisions should weigh the importance of monitoring ANC in the context of the need to control psychiatric symptoms and the patient’s terminal illness.

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 are no specific antidotes for clozapine orally disintegrating tablets. 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 (1-800-222-1222).

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 (D ₂) and the serotonin type 2A (5-HT _2A) receptors. Clozapine orally disintegrating tablets also act as an antagonist at adrenergic, cholinergic, histaminergic and other dopaminergic and serotonergic receptors.

Clozapine demonstrated binding affinity to the following receptors: histamine H ₁(K _i1.1 nM), adrenergic α _1A(K _i1.6 nM), serotonin 5-HT ₆(K _i4 nM ), serotonin 5-HT _2A(K _i5.4 nM), muscarinic M ₁(K _i6.2 nM), serotonin 5-HT ₇(K _i6.3 nM), serotonin 5-HT _2C(K _i9.4 nM), dopamine D ₄(K _i24 nM), adrenergic α _2A(K _i90 nM), serotonin 5-HT ₃(K _i95 nM), serotonin 5-HT _1A(K _i120 nM), dopamine D ₂(K _i160 nM), dopamine D ₁(K _i270 nM), dopamine D ₅(K _i454 nM), and dopamine D ₃(K _i555 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.

The efficacy of clozapine in treatment-resistant schizophrenia was established in a multicenter, randomized, double-blind, active-controlled (chlorpromazine) study in patients with a DSM-III diagnosis of schizophrenia who had inadequate responses to at least 3 different antipsychotics (from at least 2 different chemical classes) during the preceding 5 years. The antipsychotic trials must have been judged adequate; the antipsychotic dosages must have been equivalent to or greater than 1000 mg per day of chlorpromazine for a period of at least 6 weeks, each without significant reduction of symptoms. There must have been no period of good functioning within the preceding 5 years. Patients must have had a baseline score of at least 45 on the investigator-rated Brief Psychiatric Rating Scale (BPRS). On the 18-item BPRS, 1 indicates the absence of symptoms, and 7 indicates severe symptoms; the maximum potential total BPRS score is 126. At baseline, the mean BPRS score was 61. In addition, patients must have had a score of at least 4 on at least two of the following four individual BPRS items: conceptual disorganization, suspiciousness, hallucinatory behavior, and unusual thought content. Patients must have had a Clinical Global Impressions – Severity Scale score of at least 4 (moderately ill).

In the prospective, lead-in phase of the trial, all patients (N = 305) initially received single-blind treatment with haloperidol (the mean dose was 61 mg per day) for 6 weeks. More than 80% of patients completed the 6-week trial. Patients with an inadequate response to haloperidol (n = 268) were randomized to double-blind treatment with clozapine (N = 126) or chlorpromazine (N = 142). The maximum daily clozapine dose was 900 mg; the mean daily dose was > 600 mg. The maximum daily chlorpromazine dose was 1800 mg; the mean daily dose was > 1200 mg.

The primary endpoint was treatment response, predefined as a decrease in BPRS score of at least 20% and either (1) a CGI-S score of ≤ 3 (mildly ill), or (2) a BPRS score of ≤ 35, at the end of 6 weeks of treatment. Approximately 88% of patients from the clozapine and chlorpromazine groups completed the 6-week trial. At the end of six weeks, 30% of the clozapine group responded to treatment, and 4% of the chlorpromazine group responded to treatment. The difference was statistically significant (p < 0.001). The mean change in total BPRS score was -16 and -5 in the clozapine and chlorpromazine group, respectively; the mean change in the 4 key BPRS item scores was -5 and -2 in the clozapine and chlorpromazine group, respectively; and the mean change in CGI-S score was -1.2 and -0.4, in the clozapine and chlorpromazine group, respectively. These changes in the clozapine group were statistically significantly greater than in the chlorpromazine group (p < 0.001 in each analysis).

The effectiveness of clozapine in reducing the risk of recurrent suicidal behavior was assessed in the International Suicide Prevention Trial (InterSePT™, a trademark of Novartis Pharmaceuticals Corporation). This was a prospective, randomized, open-label, active-controlled, multicenter, international, parallel-group comparison of clozapine (Clozaril ^®) versus olanzapine (Zyprexa ^®, a registered trademark of Eli Lilly and Company) in 956 patients with schizophrenia or schizoaffective disorder (DSM-IV) who were judged to be at risk for recurrent suicidal behavior. Only about one-fourth of these patients (27%) were considered resistant to standard antipsychotic drug treatment. To enter the trial, patients must have met one of the following criteria:

• They had attempted suicide within the three years prior to their baseline evaluation.
• They had been hospitalized to prevent a suicide attempt within the three years prior to their baseline evaluation.
• They demonstrated moderate-to-severe suicidal ideation with a depressive component within one week prior to their baseline evaluation.
• They demonstrated moderate-to-severe suicidal ideation accompanied by command hallucinations to do self-harm within one week prior to their baseline evaluation.

Dosing regimens for each treatment group were determined by individual investigators and were individualized by patient. Dosing was flexible, with a dose range of 200-900 mg/day for clozapine and 5-20 mg/day for olanzapine. For the 956 patients who received clozapine or olanzapine in this study, there was extensive use of concomitant psychotropics: 84% with antipsychotics, 65% with anxiolytics, 53% with antidepressants, and 28% with mood stabilizers. There was significantly greater use of concomitant psychotropic medications among the patients in the olanzapine group.

The primary efficacy measure was time to (1) a significant suicide attempt, including a completed suicide; (2) hospitalization due to imminent suicide risk, including increased level of surveillance for suicidality for patients already hospitalized; or (3) worsening of suicidality severity as demonstrated by “much worsening” or “very much worsening” from baseline in the Clinical Global Impression of Severity of Suicidality as assessed by the Blinded Psychiatrist (CGI-SS-BP) scale. A determination of whether or not a reported event met criterion 1 or 2 above was made by the Suicide Monitoring Board (SMB), a group of experts blinded to patient data.

A total of 980 patients were randomized to the study and 956 received study medication. Sixty-two percent of the patients were diagnosed with schizophrenia, and the remainder (38%) were diagnosed with schizoaffective disorder. Only about one-fourth of the total patient population (27%) was identified as “treatment-resistant” at baseline. There were more males than females in the study (61% of all patients were male). The mean age of patients entering the study was 37 years of age (range: 18–69). Most patients were Caucasian (71%), 15% were Black, 1% were Asian, and 13% were classified as being of “other” races.

Patients treated with clozapine had a statistically significant longer delay in the time to recurrent suicidal behavior in comparison with olanzapine. This result should be interpreted only as evidence of the effectiveness of clozapine in delaying time to recurrent suicidal behavior and not a demonstration of the superior efficacy of clozapine over olanzapine.

The probability of experiencing (1) a significant suicide attempt, including a completed suicide, or (2) hospitalization because of imminent suicide risk, including increased level of surveillance for suicidality for patients already hospitalized, was lower for clozapine patients than for olanzapine patients at Week 104: clozapine 24% versus olanzapine 32%; 95% CI of the difference: 2%, 14% (Figure 1).

Clozapine Orally Disintegrating Tablets are available containing 100 mg of clozapine, USP.

The 100 mg tablets are peach, round, unscored tablets debossed with Cover 100on one side of the tablet and blank on the other side. They are available as follows:

NDC 51079-288-04 – Unit dose blister packages of 40 (5 cards of 8 tablets each).

Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.]

Protect from moisture.

Keep out of reach of children.

Clozapine orally disintegrating tablets must remain in the original package until used by the patient.

Drug dispensing should not ordinarily exceed a weekly supply. If a patient is eligible for ANC testing every 2 weeks, then a 2-week supply of clozapine orally disintegrating tablets can be dispensed. If a patient is eligible for ANC testing every 4 weeks, then a 4-week supply of clozapine orally disintegrating tablets can be dispensed. Dispensing should be contingent upon the ANC testing results.