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Clozapine (Clozapine) - Warnings and Precautions

 
 



WARNING: AGRANULOCYTOSIS; ORTHOSTATIC HYPOTENSION, BRADYCARDIA, AND SYNCOPE; SEIZURE; MYOCARDITIS AND CARDIOMYOPATHY; INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS

Agranulocytosis

Clozapine treatment has caused agranulocytosis, defined as an absolute neutrophil count (ANC) less than 500/mm3. Agranulocytosis can lead to serious infection and death. Prior to initiating treatment with clozapine, obtain a baseline white blood cell count (WBC) and ANC. The ANC must be greater than or equal to 2000/mm3 and the WBC must be greater than or equal to 3500/mm3 for a patient to begin treatment with clozapine. During treatment, patients must have regular monitoring of ANC and WBC. Discontinue clozapine and do not rechallenge if the ANC is less than 1000/mm3 or the WBC is less than 2000/mm3. Advise patients to immediately report symptoms consistent with agranulocytosis or infection (e.g., fever, weakness, lethargy, or sore throat) [see Dosage and Administration and Warnings and Precautions].

Because of the risk of agranulocytosis, clozapine is available only through a restricted program called the Teva Clozapine Patient Registry. Under the Teva Clozapine Patient Registry, prescribers, patients, and pharmacies must enroll in the program [see Warnings and Precautions ].

Orthostatic Hypotension, Bradycardia, Syncope

Orthostatic 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, with doses as low as 12.5 mg per day. Initiate treatment at 12.5 mg once or twice daily; titrate slowly; and use divided dosages. Use clozapine cautiously in patients with cardiovascular or cerebrovascular disease or conditions predisposing to hypotension (e.g., dehydration, use of antihypertensive medications) [see Dosage and Administration (2.2, and 2.5) and Warnings and Precautions].

Seizures

Seizures have occurred with clozapine treatment. The risk is dose-related. Initiate treatment at 12.5 mg, titrate gradually, and use divided dosing. Use caution when administering clozapine to patients with a history of seizures or other predisposing risk factors for seizure (CNS pathology, medications that lower the seizure threshold, alcohol abuse). Caution patients about engaging in any activity where sudden loss of consciousness could cause serious risk to themselves or others [see Dosage and Administration Warnings and Precautions].

Myocarditis and Cardiomyopathy

Fatal myocarditis and cardiomyopathy have occurred with clozapine treatment. Discontinue clozapine and obtain a cardiac evaluation upon suspicion of these reactions. Generally, patients with clozapine-related myocarditis or cardiomyopathy should not be rechallenged with clozapine. Consider the possibility of myocarditis or cardiomyopathy if chest pain, tachycardia, palpitations, dyspnea, fever, flu-like symptoms, hypotension, or ECG changes occur [see Warnings and Precautions ].

Increased Mortality in Elderly Patients with Dementia-Related Psychosis

Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Clozapine is not approved for use in patients with dementia-related psychosis [see Warnings and Precautions].

 

WARNINGS AND PRECAUTIONS

Agranulocytosis

Background

Agranulocytosis, defined as an ANC of less than 500/mm3, has been estimated to occur in association with clozapine use at a cumulative incidence at 1 year of approximately 1.3%, based on the occurrence of 15 US cases out of 1743 patients exposed to clozapine tablets during their clinical testing prior to domestic marketing. All of these cases occurred at a time when the need for close monitoring of WBC counts was already recognized. A hematologic risk analysis was conducted based upon the available information in the CLOZARIL® National Registry for US patients. Based upon a cut-off date of April 30, 1995, the incidence rates of agranulocytosis based upon a weekly monitoring schedule rose steeply during the first two months of therapy, peaking in the third month. Among clozapine patients who continued the drug beyond the third month, the weekly incidence of agranulocytosis fell a substantial degree. After 6 months, the weekly incidence of agranulocytosis declines still further; however, it never reaches zero. It should be noted that any type of reduction in the frequency of monitoring WBC counts may result in an increased incidence of agranulocytosis.

Risk Factors

Experience from clinical development, as well as from examples in the medical literature, suggests that patients who have developed agranulocytosis during clozapine therapy are at increased risk of subsequent episodes of agranulocytosis. Analysis of WBC count data from the CLOZARIL® National Registry also suggests that patients who have an initial episode of moderate leukopenia (3000/mm3 > WBC count ≥ 2000/mm3) are at an increased risk of subsequent episodes of agranulocytosis. Except for bone-marrow suppression during initial clozapine therapy, there are no other established risk factors based on worldwide experience for the development of agranulocytosis in association with clozapine use. However, a disproportionate number of the US cases of agranulocytosis occurred in patients of Jewish background compared to the overall proportion of such patients exposed during domestic development of clozapine. Most of the US cases of agranulocytosis occurred within 4 to 10 weeks of exposure, but neither dose nor duration is a reliable predictor of this problem. Agranulocytosis associated with other antipsychotic drugs has been reported to occur with a greater frequency in women, the elderly, and in patients who are cachectic or have serious underlying medical illness; such patients may also be at particular risk with clozapine, although this has not been definitively demonstrated.

WBC Count and ANC Clinical Monitoring Schedule

Clozapine is available only through a distribution system that ensures monitoring of WBC count and ANC according to the schedule described below prior to delivery of the next supply of medication.

As described in Table 2, patients who are being treated with clozapine must have a baseline WBC count and ANC before initiation of treatment, and a WBC count and ANC every week for the first 6 months. Thereafter, if acceptable WBC counts and ANCs (WBC count ≥ 3500/mm3 and ANC ≥ 2000/mm3) have been maintained during the first 6 months of continuous therapy, WBC counts and ANCs can be monitored every 2 weeks for the next 6 months. Thereafter, if acceptable WBC counts and ANCs (WBC count ≥ 3500/mm3 and ANC ≥ 2000/mm3) have been maintained during the second 6 months of continuous therapy, WBC count and ANC can be monitored every 4 weeks.

When treatment with clozapine is discontinued (regardless of the reason), WBC count and ANC must be monitored weekly for at least 4 weeks from the day of discontinuation or until WBC count ≥ 3500/mm3 and ANC ≥ 2000/mm3.

Table 2 provides a summary of the frequency of monitoring that should occur based on various stages of therapy (e.g., initiation of therapy) or results from WBC count and ANC monitoring tests (e.g., moderate leukopenia). The text that follows should be consulted for additional details regarding the treatment of patients under the various conditions (e.g., severe leukopenia).

Advise patients to immediately report the appearance of signs/symptoms consistent with agranulocytosis or infection (e.g., fever, weakness, lethargy, or sore throat) at any time during clozapine therapy. Such patients should have a WBC count and an ANC performed promptly.

Table 2. Frequency of Monitoring Based on Stage of Therapy or Results from WBC Count and ANC Monitoring Tests

Situation

Hematological Values for Monitoring

Frequency of WBC Count and ANC Monitoring

Initiation of therapy

WBC count ≥ 3500/mm3

Weekly for 6 months

and

ANC ≥ 2000/mm3

Note: Do not initiate in patients with a history of clozapine-induced agranulocytosis or severe granulocytopenia.

6 to 12 months of therapy

WBC ≥ 3500/mm3

Every 2 weeks for 6 months

and

ANC ≥ 2000/mm3

12 months of therapy

WBC ≥ 3500/mm3

Every 4 weeks ad infinitum

and

ANC ≥ 2000/mm3

Immature forms present

N/A

Repeat WBC and ANC

Discontinuation of therapy

N/A

Weekly for at least 4 weeks from day of discontinuation or until WBC ≥ 3500/mm3 and ANC ≥ 2000/mm3

Substantial drop in WBC or ANC

Single drop or cumulative drop within 3 weeks of: WBC ≥ 3000/mm3 or

1. Repeat WBC and ANC 2. If repeat values are: WBC 3000/mm3 to 3500 and ANC > 2000/mm3, then monitor twice weekly

ANC ≥ 1500/mm3

Mild leukopenia

If WBC 3000 mm3 to < 3500/mm3

Twice weekly until WBC > 3500/mm3 and

and/or

and/or

ANC > 2000/mm3 then return to previous monitoring

Mild granulocytopenia

ANC 1500/mm3 to < 2000/mm3

frequency

Moderate leukopenia

WBC 2000/mm3 to < 3000/mm3

1. Interrupt therapy

2. Daily until WBC > 3000/mm3 and ANC > 1500/mm3

and/or

and/or

3. Twice weekly until WBC > 3500/mm3 and

ANC > 2000/mm3

Moderate granulocytopenia

ANC 1000/mm3 to < 1500/mm3

4. May rechallenge when WBC > 3500/mm3 and ANC > 2000/mm3

5. If rechallenged, monitor weekly for 1 year before returning to the usual monitoring schedule of every 2 weeks for 6 months and then every 4 weeks ad infinitum

Severe leukopenia

WBC count < 2000/mm3

1. Discontinue treatment and do not rechallenge patient 2. Monitor until normal and for at least four weeks from day of discontinuation as follows:

-Daily until WBC > 3000/mm3 and ANC > 1500/mm3

-Twice weekly until WBC > 3500/mm3 and ANC > 2000/mm3

-Weekly after WBC > 3500/mm3

and/or

and/or

Severe granulocytopenia

ANC < 1000/mm3

Agranulocytosis

ANC < 500/mm3

1. Discontinue treatment and do not rechallenge patient

2. Monitor until normal and for at least four weeks from day of discontinuation as follows:

-Daily until WBC > 3000/mm3 and ANC > 1500/mm3

-Twice weekly until WBC > 3500/mm3 and ANC > 2000/mm3

-Weekly after WBC > 3500/mm3

WBC = White blood cell

ANC = Absolute neutrophil count

Decrements in WBC Count and/or ANC

Consult Table 2 above to determine how to monitor patients who experience decrements in WBC count and/or ANC at any point during treatment. Additionally, patients should be carefully monitored for flu-like symptoms or other symptoms suggestive of infection.

Nonrechallengeable Patients

If the total WBC count falls below 2000/mm3 or the ANC falls below 1000/mm3, bone-marrow aspiration should be considered to ascertain granulopoietic status and patients should not be rechallenged with clozapine. Protective isolation with close observation may be indicated if granulopoiesis is determined to be deficient. Should evidence of infection develop, the patient should have appropriate cultures performed and an appropriate antibiotic regimen instituted.

Patients discontinued from clozapine therapy due to significant granulopoietic suppression have been found to develop agranulocytosis upon rechallenge, often with a shorter latency on re-exposure. To reduce the chances of rechallenge occurring in patients who have experienced significant bone-marrow suppression during clozapine therapy, a single, national master file (i.e., Nonrechallengeable Database) is confidentially maintained.

Treatment of Rechallengeable Patients

Patients may be rechallenged with clozapine if their WBC count does not fall below 2000/mm3 and the ANC does not fall below 1000/mm3. However, analysis of the data from the CLOZARIL® National Registry suggests that patients who have an initial episode of moderate leukopenia (3000/mm3 > WBC count ≥ 2000/mm3) have up to a 12 fold increased risk of having a subsequent episode of agranulocytosis when rechallenged as compared to the full cohort of patients treated with clozapine. Although clozapine tablets therapy may be resumed if no symptoms of infection develop and when the WBC count rises above 3500/mm3 and the ANC rises above 2000/mm3, prescribers are strongly advised to consider whether the benefit of continuing clozapine tablets treatment outweighs the increased risk of agranulocytosis.

Analyses of the CLOZARIL® National Registry have shown an increased risk of having a subsequent episode of granulopoietic suppression up to a year after recovery from the initial episode. Therefore, as noted in Table 2, patients must undergo weekly WBC count and ANC monitoring for one year following recovery from an episode of moderate leukopenia and/or moderate granulocytopenia regardless of when the episode develops. If acceptable WBC counts and ANC (WBC count ≥ 3500/mm3 and ANC ≥ 2000/mm3) have been maintained during the year of weekly monitoring, WBC counts can be monitored every 2 weeks for the next 6 months. If acceptable WBC counts and ANC (WBC count ≥ 3500/mm3 and ANC ≥ 2000/mm3) continue to be maintained during the 6 months of every-2-week monitoring, WBC counts can be monitored every 4 weeks thereafter, ad infinitum.

Interruptions in Therapy

Figure 1 provides instructions regarding re-initiating therapy and subsequently the frequency of WBC count and ANC monitoring after a period of interruption.

Figure 1. Resuming Monitoring Frequency after Interruption of Therapy

* transitions to reduce frequency of monitoring only permitted if all WBC counts ≥ 3500/mm3 and ANCs ≥ 2000/mm3

Teva Clozapine Patient Registry Because of the Risk of Agranulocytosis

Because of the risk of agranulocytosis, clozapine is available only through a restricted program called the Teva Clozapine Patient Registry. Under the Teva Clozapine Patient Registry, prescribers, patients, pharmacies, and distributors must enroll in the program.

Required components of the Teva Clozapine Patient Registry are:

  • •Healthcare professionals who prescribe clozapine must enroll in the program and comply with the Registry requirements.
  • •Pharmacies that dispense clozapine must enroll in the program and comply with the Registry requirements.
  • •Routine monitoring and submission of laboratory results (WBC and ANC) is required during treatment with clozapine [see Warnings and Precautions ].
  • •Patients that receive clozapine must be enrolled in a registry.

Further information is available at https://www.clozapineregistry.com or 1-800-507-8334.

Orthostatic Hypotension, Bradycardia, and Syncope

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]. Consider reducing the dose if hypotension occurs. When restarting patients who have had even a brief interval off clozapine (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 ].

 

Use clozapine 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).

Seizures

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 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 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

Myocarditis and cardiomyopathy have occurred with the use of clozapine. These reactions can be fatal. Discontinue clozapine 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 clozapine. However, if the benefit of clozapine treatment is judged to outweigh the potential risks of recurrent myocarditis or cardiomyopathy, the clinician may consider rechallenge with clozapine in consultation with a cardiologist, after a complete cardiac evaluation, and under close monitoring.

Consider the possibility of myocarditis or cardiomyopathy in patients receiving clozapine 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 two 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 clozapine. 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.

Increased Mortality in Elderly Patients with Dementia-Related Psychosis

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 is not approved for the treatment of patients with dementia-related psychosis [See Boxed Warning] .

Eosinophilia

Eosinophilia, defined as a blood eosinophil count of greater than 700/mm3, 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 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 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.

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 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 therapy and rechallenge after the eosinophil count decreases should be based on the overall clinical assessment, in consultation with an internist or hematologist.

QT Interval Prolongation

QT prolongation, Torsades de Pointes and other life-threatening ventricular arrhythmias, cardiac arrest, and sudden death have occurred with clozapine treatment. When prescribing clozapine, 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 clozapine, 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 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.

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

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.

Metabolic Changes

Atypical antipsychotic drugs, including clozapine have been associated with metabolic changes that can increase cardiovascular and cerebrovascular risk. These metabolic changes include hyperglycemia, dyslipidemia, and body weight gain. While atypical antipsychotic drugs may produce some metabolic changes, each drug in the class has its own specific risk profile.

Hyperglycemia and Diabetes Mellitus

Hyperglycemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported in patients treated with atypical antipsychotics including clozapine. 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 clozapine 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 anti-diabetic 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 clozapine and chlorpromazine groups were +11 mg/dL and +4 mg/dL respectively. A higher proportion of the clozapine group demonstrated categorical increases from baseline in fasting glucose concentrations, compared to the chlorpromazine group (Table 3). The clozapine doses were 100 to 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 clozapine and chlorpromazine.

Table 3. 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 (%)

Normal (< 100 mg/dL)

Clozapine

198

53 (27)

to

Fasting Glucose

High (≥ 126 mg/dL)

Chlorpromazine

135

14 (10)

Borderline (100 to 125 mg/dL)

Clozapine

57

24 (42)

to

High (≥ 126 mg/dL)

Chlorpromazine

43

12 (28)

Dyslipidemia

Undesirable alterations in lipids have occurred in patients treated with atypical antipsychotics, including clozapine. Clinical monitoring, including baseline and periodic follow-up lipid evaluations in patients using clozapine, is recommended.

In a pooled data analysis of 10 studies in adult subjects with schizophrenia, clozapine 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 clozapine group and 15 mg/dL in the chlorpromazine group. In a pooled data analysis of 2 studies in adult subjects with schizophrenia, clozapine treatment was associated with increases in fasting serum triglyceride. The mean increase in fasting triglyceride was 71 mg/dL (54%) in the clozapine group and 39 mg/dL (35%) in the chlorpromazine group (Table 4). In addition, clozapine treatment was associated with categorical increases in serum total cholesterol and triglyceride, as illustrated in Table 5. The proportion of patients with categorical increases in total cholesterol or fasting triglyceride increased with the duration of exposure. The median duration of clozapine and chlorpromazine exposure was 45 days and 38 days, respectively. The clozapine dose range was 100 mg to 900 mg daily; the maximum chlorpromazine dose was 1800 mg daily.

Table 4. 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 (%)

Clozapine (N = 334)

184

+13 (7)

Chlorpromazine (185)

182

+15 (8)

Baseline triglyceride concentration (mg/dL)

Change from baseline mg/dL (%)

Clozapine (N = 6)

130

+71 (54)

Chlorpromazine (N = 7)

110

+39 (35)

Table 5. 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 (%)

Clozapine

334

111 (33)

Increase by ≥ 40 mg/dL

Chlorpromazine

185

46 (25)

Total Cholesterol (random or fasting)

Normal (< 200 mg/dL)

Clozapine

222

18 (8)

to

Chlorpromazine

132

3 (2)

High (≥ 240 mg/dL)

Borderline

Clozapine

79

30 (38)

(200 to 239 mg/dL)

to

Chlorpromazine

34

14 (41)

High (≥ 240 mg/dL)

Triglycerides (fasting)

Increase by ≥ 50 mg/dL

Clozapine

6

3 (50)

Chlorpromazine

7

3(43)

Normal (< 150 mg/dL)

Clozapine

4

0 (0)

to

Chlorpromazine

6

2 (33)

High (≥ 200 mg/dL)

Borderline

Clozapine

1

1 (100)

(≥ 150 mg/dL and < 200 mg/dL) to High (≥ 200 mg/dL)

Chlorpromazine

1

0 (0)

Weight Gain

Weight gain has occurred with the use of antipsychotics, including clozapine. Monitor weight during treatment with clozapine. Table 6 summarizes the data on weight gain by the duration of exposure pooled from 11 studies with clozapine and active comparators. The median duration of exposure was 609, 728, and 42 days, in the clozapine, olanzapine, and chlorpromazine groups, respectively.

Table 6. Mean Change in Body Weight (kg) by duration of exposure from studies in adult subjects with schizophrenia

Metabolic parameter

Exposure duration

Clozapine (N = 669)

Olanzapine (N = 442)

Chlorpromazine (N = 155)

n

Mean

n

Mean

n

Mean

2 weeks (Day 11 to 17)

6

+0.9

3

+0.7

2

-0.5

Weight change from baseline

4 weeks (Day 21 to 35)

23

+0.7

8

+0.8

17

+0.6

8 weeks (Day 49 to 63)

12

+1.9

13

+1.8

16

+0.9

12 weeks (Day 70 to 98)

17

+2.8

5

+3.1

0

0

24 weeks (154 to 182)

42

-0.6

12

+5.7

0

0

48 weeks (Day 322 to 350)

3

+3.7

3

+13.7

0

0

Table 7 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 clozapine, olanzapine, and chlorpromazine groups, respectively.

Table 7. Proportion of adult subjects in schizophrenia studies with weight gain ≥ 7% relative to baseline body weight

Weight change

Clozapine

Olanzapine

Chlorpromazine

N

669

442

155

≥ 7% (inclusive)

236 (35%)

203 (46%)

13 (8%)

Neuroleptic Malignant Syndrome

Antipsychotic drugs including clozapine 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., agranulocytosis, infection, heat stroke, primary CNS pathology, central anticholinergic toxicity, extrapyramidal symptoms, and drug fever).

The management of NMS should include immediate discontinuation of antipsychotic drugs and other drugs not essential to concurrent therapy, 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 clozapine monotherapy and with concomitant CNS-active medications, including lithium.

Fever

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 agranulocytosis or infection. Consider the possibility of NMS [see Warnings and Precautions ].

Pulmonary Embolism

Pulmonary embolism and deep vein thrombosis have occurred in patients treated with clozapine tablets. 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.

Anticholinergic Toxicity

Clozapine has potent anticholinergic effects. Treatment with clozapine can result in CNS and peripheral anticholinergic toxicity. Use with caution in the presence of narrow-angle glaucoma, concomitant anticholinergic medications, prostatic hypertrophy, or other conditions in which anticholinergic effects can lead to significant adverse reactions.

Treatment with clozapine can result in gastrointestinal adverse reactions, including constipation, intestinal obstruction, fecal impaction, and paralytic ileus. Such reactions can be fatal. Constipation should be initially treated by ensuring adequate hydration and use of ancillary therapy such as bulk laxatives. Consultation with a gastroenterologist is advisable in more serious cases.

Interference with Cognitive and Motor Performance

Clozapine 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 does not affect them adversely. These reactions may be dose-related. Consider reducing the dose if they occur.

Tardive Dyskinesia

Tardive dyskinesia (TD) has occurred in patients treated with antipsychotic drugs, including clozapine. 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 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 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.

Cerebrovascular Adverse Reactions

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

Recurrence of Psychosis and Cholinergic Rebound after Abrupt Discontinuation of Clozapine

If abrupt discontinuation of clozapine is necessary (because of agranulocytosis or another medical condition, for example), monitor carefully for the recurrence of psychotic symptoms and adverse reactions related to cholinergic rebound, such as profuse sweating, headache, nausea, vomiting and diarrhea.

USE IN SPECIFIC POPULATIONS

Pregnancy

Teratogenic Effects

Pregnancy Category B

Risk Summary

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/m2 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, clozapine tablets should be used during pregnancy only if clearly needed.

Clinical Considerations

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]. 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.

Animal Data

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/m2 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 F1or F2 generations at doses up to 0.4 times the MRHD of 900 mg/day on a mg/m2 body surface area basis.

Nursing Mothers

Clozapine is present in human milk. Because of the potential for serious adverse reactions in nursing infants from clozapine, 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.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

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

Orthostatic hypotension and tachycardia can occur with clozapine treatment [see Boxed Warning and Warnings and Precautions ]. 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].

 

Carefully select clozapine 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 ].

Patients with Renal or Hepatic Impairment

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].

CYP2D6 Poor Metabolizers

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 Clinical Pharmacology].

Page last updated: 2014-06-12

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