Source: FDA, National Drug Code (US) Revision Year: 2020
CLOZARIL is contraindicated in patients with a history of serious hypersensitivity to clozapine (e.g., photosensitivity, vasculitis, erythema multiforme, or Stevens-Johnson Syndrome) or any other component of CLOZARIL [see Adverse Reactions (6.2)].
CLOZARIL can cause neutropenia (a low absolute neutrophil count (ANC)), defined as a reduction below pre-treatment normal levels of blood neutrophils. The ANC is usually available as a component of the complete blood count (CBC), including differential, and is more relevant to drug-induced neutropenia than is the white blood cell (WBC) count. The ANC may also be calculated using the following formula: ANC equals the Total WBC count multiplied by the total percentage of neutrophils obtained from the differential (neutrophil “segs” plus neutrophil “bands”). Other granulocytes (basophils and eosinophils) contribute minimally to neutropenia and their measurement is not necessary [see Adverse Reactions (6.2)]. Neutropenia may be mild, moderate, or severe (see Tables 2 and 3). To improve and standardize understanding, “severe neutropenia” replaces the previous terms severe leukopenia, severe granulocytopenia, or agranulocytosis.
Severe neutropenia, ANC less than (<) 500/µL, occurs in a small percentage of patients taking CLOZARIL and is associated with an increase in the risk of serious and potentially fatal infections. Risk of neutropenia appears greatest during the first 18 weeks on treatment and then declines. The mechanism by which CLOZARIL causes neutropenia is unknown and is not dose-dependent.
Two separate management algorithms are provided below, the first for patients in the general population, and the second for patients identified to have baseline neutropenia.
Obtain a CBC, including the ANC value, prior to initiating treatment with CLOZARIL to ensure the presence of a normal baseline neutrophil count (equal to or greater than 1500/µL) and to permit later comparisons. Patients in the general population with an ANC equal to or greater than (≥)1500/µL are considered within normal range (Table 2) and are eligible to initiate treatment. Weekly ANC monitoring is required for all patients during the first 6 months of treatment. If a patient’s ANC remains equal to or greater than 1500/µL for the first 6 months of treatment, monitoring frequency may be reduced to every 2 weeks for the next 6 months. If the ANC remains equal to or greater than 1500/µL for the second 6 months of continuous therapy, ANC monitoring frequency may be reduced to once every 4 weeks thereafter.
Table 2. CLOZARIL Treatment Recommendations Based on Absolute Neutrophil Count (ANC) Monitoring for the General Patient Population:
| ANC Level | CLOZARIL Treatment Recommendations | ANC Monitoring |
|---|---|---|
| Normal range (≥1500/µL) | • Initiate treatment • If treatment interrupted: •• <30 days, continue monitoring as before •• ≥30 days, monitor as if new patient | • Weekly from initiation to 6 months • Every 2 weeks from 6 to 12 months • Monthly after 12 months |
| • Discontinuation for reasons other than neutropenia | • See Section 2.4 | |
| Mild Neutropenia (1000 to 1499/µL)* | • Continue treatment | • Three times weekly until ANC ≥1500/µL • Once ANC ≥1500/µL, return to patient’s last “Normal Range” ANC monitoring interval** |
| Moderate Neutropenia (500 to 999/µL)* | • Recommend hematology consultation • Interrupt treatment for suspected clozapine induced neutropenia • Resume treatment once ANC ≥1000/µL | • Daily until ANC ≥1000/µL, then • Three times weekly until ANC ≥1500/µL • Once ANC ≥1500/µL, check ANC weekly for 4 weeks, then return to patient’s last “Normal Range” ANC monitoring interval** |
| Severe Neutropenia (less than 500/µL)* | • Recommend hematology consultation • Interrupt treatment for suspected clozapine-induced neutropenia • Do not rechallenge unless prescriber determines benefits outweigh risks | • Daily until ANC ≥1000/µL, then • Three times weekly until ANC ≥1500/µL • If patient rechallenged, resume treatment as a new patient under “Normal Range” monitoring once ANC ≥1500/µL |
* Confirm all initial reports of ANC less than 1500/ µL with a repeat ANC measurement within 24 hours
** If clinically appropriate
Benign ethnic neutropenia (BEN) is a condition observed in certain ethnic groups whose average ANC values are lower than “standard” laboratory ranges for neutrophils. It is most commonly observed in individuals of African descent (approximate prevalence of 25-50%), some Middle Eastern ethnic groups, and in other non-Caucasian ethnic groups with darker skin. BEN is more common in men. Patients with BEN have normal hematopoietic stem-cell number and myeloid maturation, are healthy, and do not suffer from repeated or severe infections. They are not at increased risk for developing CLOZARIL-induced neutropenia. Additional evaluation may be needed to determine if baseline neutropenia is due to BEN. Consider hematology consultation before initiating or during CLOZARIL treatment as necessary.
Patients with BEN require a different ANC algorithm for CLOZARIL management due to their lower baseline ANC levels. Table 3 provides guidelines for managing CLOZARIL treatment and ANC monitoring in patients with BEN.
Table 3. Patients with Benign Ethnic Neutropenia (BEN); CLOZARIL Treatment Recommendations Based on Absolute Neutrophil Count (ANC) Monitoring:
| ANC Level | Treatment Recommendations | ANC Monitoring |
|---|---|---|
| Normal BEN Range (Established ANC baseline ≥1000/µL) | • Obtain at least two baseline ANC levels before initiating treatment • If treatment interrupted •• <30 days, continue monitoring as before •• ≥30 days, monitor as if new patient | • Weekly from initiation to 6 months • Every 2 weeks from 6 to 12 months • Monthly after 12 months |
| • Discontinuation of treatment for reasons other than neutropenia | • See Section 2.4 | |
| BEN Neutropenia 500 to 999/µL* | • Recommend hematology consultation • Continue treatment | • Three times weekly until ANC ≥1000/µL or ≥ patient’s known baseline • Once ANC ≥1000/µL or at patient’s known baseline, check ANC weekly for 4 weeks, then return to patient’s last “Normal BEN Range” ANC monitoring interval.** |
| BEN Severe Neutropenia less than 500/µL* | • Recommend hematology consultation • Interrupt treatment for suspected clozapine-induced neutropenia • Do not rechallenge unless prescriber determines benefits outweigh risks | • Daily until ANC ≥500/µL, then • Three times weekly until ANC ≥ patient’s baseline • If patient rechallenged, resume treatment as a new patient under “Normal Range” monitoring once ANC ≥1000/µL or at patient’s baseline |
* Confirm all initial reports of ANC less than 1500/µL with a repeat ANC measurement within 24 hours
** If clinically appropriate
For some patients who experience severe CLOZARIL-related neutropenia, the risk of serious psychiatric illness from discontinuing CLOZARIL treatment may be greater than the risk of rechallenge (e.g., patients with severe schizophrenic illness who have no treatment options other than CLOZARIL). A hematology consultation may be useful in deciding to rechallenge a patient. In general, however, do not rechallenge patients who develop severe neutropenia with CLOZARIL or a clozapine product.
If a patient will be rechallenged, the clinician should consider thresholds provided in Tables 2 and 3, the patient’s medical and psychiatric history, a discussion with the patient and his/her caregiver about the benefits and risks of CLOZARIL rechallenge, and the severity and characteristics of the neutropenic episode.
It is unclear if concurrent use of other drugs known to cause neutropenia increases the risk or severity of CLOZARIL-induced neutropenia. There is no strong scientific rationale to avoid CLOZARIL treatment in patients concurrently treated with these drugs. If CLOZARIL is used concurrently with an agent known to cause neutropenia (e.g., some chemotherapeutic agents), consider monitoring patients more closely than the treatment guidelines provided in Tables 2 and 3. Consult with the treating oncologist in patients receiving concomitant chemotherapy.
CLOZARIL is 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:
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 (2.2)]. Consider reducing the dose if hypotension occurs. When restarting patients who have had even a brief interval off CLOZARIL (i.e., 2 days or more since the last dose), re-initiate treatment at 12.5 mg once daily or twice daily [see Dosage and Administration (2.5)].
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 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 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 recurrent myocarditis or cardiomyopathy, the clinician may consider rechallenge with CLOZARIL in consultation with a cardiologist, after a complete cardiac evaluation, and under close monitoring.
Consider the possibility of myocarditis or cardiomyopathy in patients receiving CLOZARIL 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 most frequently presents 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 and cardiomyopathy can occur at any period during treatment with CLOZARIL. It is common for nonspecific flu-like symptoms such as malaise, myalgia, pleuritic chest pain, and low-grade fevers to precede more overt signs of heart failure. Typical laboratory findings include elevated troponin I or T, elevated creatinine kinase-MB, peripheral eosinophilia, and elevated C-reactive protein (CRP). Chest roentgenogram may demonstrate cardiac silhouette enlargement, and cardiac imaging (echocardiogram, radionucleotide studies, or cardiac catheterization) may reveal evidence of left ventricular dysfunction. In patients who are diagnosed with cardiomyopathy while taking CLOZARIL mitral valve incompetence has been reported. These cases reported either mild or moderate mitral regurgitation on two-dimensional echocardiography. In patients with suspected cardiomyopathy, consider a 2D-echo Doppler examination to identify mitral valve incompetence.
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, resulting in intestinal obstruction, fecal impaction, megacolon and intestinal ischemia or infarction [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 (5.16), 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, 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) |
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) toHigh (≥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 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 (5.8), 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.
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.
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 (2.4), 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.
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 (N=126) (%) | Chlorpromazine (N=142) (%) |
|---|---|---|
| Sedation | 21 | 13 |
| Tachycardia | 17 | 11 |
| Constipation | 16 | 12 |
| Dizziness | 14 | 16 |
| Hypotension | 13 | 38 |
| Fever (hyperthermia) | 13 | 4 |
| Hypersalivation | 13 | 1 |
| Hypertension | 12 | 5 |
| Headache | 10 | 10 |
| Nausea/vomiting | 10 | 12 |
| Dry mouth | 5 | 20 |
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 |
| Tremor | 6 |
| Syncope | 6 |
| Disturbed Sleep/Nightmares | 4 |
| Restlessness | 4 |
| Hypokinesia/Akinesia | 4 |
| 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):
| Adverse Reactions | CLOZARIL N=479 % Reporting | Olanzapine N=477 % 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 |
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, 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, and periorbital edema.
Endocrine System: Pseudopheochromocytoma
Gastrointestinal System: Acute pancreatitis, dysphagia, salivary gland swelling, colitis, megacolon, intestinal ischemia or infarction.
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, 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.
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 (2.6), 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 (2.6)].
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 (2.6)].
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 (2.6)].
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 (2.6)].
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 (5.8, 5.16)].
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 (5.10)].
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).
Pregnancy Category B.
There are no adequate or well-controlled studies of clozapine in pregnant women.
Reproduction studies have been performed in rats and rabbits at doses up to 0.4 and 0.9 times, respectively, the maximum recommended human dose (MRHD) of 900 mg/day on a mg/m 2 body surface area basis. The studies revealed no evidence of impaired fertility or harm to the fetus due to clozapine. Because animal reproduction studies are not always predictive of human response, CLOZARIL should be used during pregnancy only if clearly needed.
Consider the risk of exacerbation of psychosis when discontinuing or changing treatment with antipsychotic medications during pregnancy and postpartum. Consider early screening for gestational diabetes for patients treated with antipsychotic medications [see Warnings and Precautions (5.11)]. Neonates exposed to antipsychotic drugs during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery. Monitor neonates for symptoms of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding difficulties. The severity of complications can vary from self-limited symptoms to some neonates requiring intensive care unit support and prolonged hospitalization.
In embryofetal developmental studies, clozapine had no effects on maternal parameters, litter sizes, or fetal parameters when administered orally to pregnant rats and rabbits during the period of organogenesis at doses up to 0.4 and 0.9 times, respectively, the MRHD of 900 mg/day on a mg/m 2 body surface area basis.
In peri/postnatal developmental studies, pregnant female rats were administered clozapine over the last third of pregnancy and until day 21 postpartum. Observations were made on fetuses at birth and during the postnatal period; the offspring were allowed to reach sexual maturity and mated. Clozapine caused a decrease in maternal body weight but had no effects on litter size or body weights of either F1 or F2 generations at doses up to 0.4 times the MRHD of 900 mg/day on a mg/m 2 body surface area basis.
CLOZARIL is present in human milk. Because of the potential for serious adverse reactions in nursing infants from CLOZARIL, 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 CLOZARIL to determine whether those over 65 years of age differ from younger subjects in their response to CLOZARIL.
Orthostatic hypotension and tachycardia can occur with CLOZARIL treatment [see Boxed Warning and 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 CLOZARIL, such as urinary retention and constipation [see Warnings and Precautions (5.16)].
Carefully select CLOZARIL 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 (2.7), 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 (2.7), Clinical Pharmacology (12.3)].
For hospice patients (i.e., terminally ill patients with an estimated life expectancy of six 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.
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