The following adverse reactions are discussed in more detail in other sections of the labeling:
- Agranulocytosis [see WARNINGS AND PRECAUTIONS].
- Orthostatic Hypotension, Bradycardia, and Syncope [see WARNINGS AND PRECAUTIONS].
- Seizures [see WARNINGS AND PRECAUTIONS].
- Myocarditis and Cardiomyopathy [see WARNINGS AND PRECAUTIONS].
- Increased Mortality in Elderly Patients with Dementia-Related Psychosis [see WARNINGS AND PRECAUTIONS].
- Eosinophilia [see WARNINGS AND PRECAUTIONS].
- QT Interval Prolongation [see WARNINGS AND PRECAUTIONS].
- Metabolic Changes (Hyperglycemia and Diabetes Mellitus, Dyslipidemia, and Weight Gain) [see WARNINGS AND PRECAUTIONS].
- Neuroleptic Malignant Syndrome [see WARNINGS AND PRECAUTIONS].
- Fever [see WARNINGS AND PRECAUTIONS].
- Pulmonary Embolism [see WARNINGS AND PRECAUTIONS].
- Anticholinergic Toxicity [see WARNINGS AND PRECAUTIONS].
- Interference with Cognitive and Motor Performance [see WARNINGS AND PRECAUTIONS].
- Tardive Dyskinesia [see WARNINGS AND PRECAUTIONS].
- Cerebrovascular Adverse Reactions [see WARNINGS AND PRECAUTIONS].
- Recurrence of Psychosis and Cholinergic Rebound after Abrupt Discontinuation [see WARNINGS AND PRECAUTIONS].
Clinical Trials Experience
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 8 summarizes the most commonly reported adverse reactions ( ≥ 5%) in clozapine-treated patients (compared to chlorpromazinetreated patients) in the pivotal, 6-week, controlled trial in treatment-resistant schizophrenia.
Table 8: Common Adverse Reactions ( ≥ 5%) in the 6-Week, Randomized, Chlorpromazine-controlled Trial in Treatment-Resistant Schizophrenia
(N = 126)
(N = 142)
Table 9 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 9: Adverse Reactions ( ≥ 2%) Reported in Clozapine-treated Patients (N=842) across all Clozapine Studies (excluding the 2-year InterSePT™ Study)
|Body System Adverse Reaction||Clozapine
N = 842
Percentage of Patients
|Central Nervous System|
|Autonomic Nervous System|
|† Rate based on population of approximately 1700 exposed during premarket clinical evaluation of clozapine.|
Table 10 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.
Table 10: Incidence of Adverse Reactions in Patients Treated with Clozapine or Olanzapine in the InterSePT™ Study ( ≥ 10% in the clozapine or olanzapine group)
N = 479
N = 477
|Dizziness (excluding vertigo)||27%||12%|
Class effect: Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment. Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first generation antipsychotic drugs. An elevated risk of acute dystonia is observed in males and younger age groups.
The following adverse reactions have been identified during post-approval use of clozapine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Central Nervous System
Delirium, EEG abnormal, myoclonus, paresthesia, possible cataplexy, status epilepticus, obsessive compulsive symptoms, and post-discontinuation cholinergic rebound adverse reactions.
Atrial or ventricular fibrillation, periorbital edema, and myocardial infarction, Ventricular tachycardia, cardiac arrest, QT prolongation, and Torsades de Pointes.
Acute pancreatitis, dysphagia, salivary gland swelling.
Cholestasis, hepatitis, jaundice, hepatotoxicity, hepatic steatosis, hepatic necrosis, hepatic fibrosis, hepatic cirrhosis, liver injury (hepatic, cholestatic, and mixed), and liver failure.
Acute interstitial nephritis, nocturnal enuresis, priapism, and renal failure.
Hypersensitivity reactions: photosensitivity, vasculitis, erythema multiforme, and Stevens-Johnson Syndrome.
Myasthenic syndrome and rhabdomyolysis.
Aspiration, pleural effusion, pneumonia, lower respiratory tract infection.
Hemic and Lymphatic System
Deep-vein thrombosis, elevated hemoglobin/hematocrit, erythrocyte sedimentation rate (ESR) increased, sepsis, thrombocytosis, and thrombocytopenia.
Creatine phosphokinase elevation, hyperuricemia, hyponatremia, and weight loss.