- Clinician Information:
Versacloz Side Effects Center
Medical Editor: John P. Cunha, DO, FACOEP
Versacloz (clozapine) Oral Suspension is an antipsychotic medication used to treat severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment. Common side effects include sedation, rapid heartbeat, constipation, dizziness, low or high blood pressure, fever, excessive salivation, headache, nausea or vomiting, or dry mouth.
The starting dose of Versacloz is 12.5 mg once daily or twice daily. The total daily dose can be increased in increments of 25 mg to 50 mg per day, if well-tolerated, to achieve a target dose of 300 mg to 450 mg per day (administered in divided doses) by the end of 2 weeks. Versacloz may interact with fluvoxamine, ciprofloxacin, enoxacin, oral contraceptives, caffeine, cimetidine, escitalopram, erythromycin, paroxetine, bupropion, fluoxetine, quinidine, duloxetine, terbinafine, sertraline, tobacco smoke, carbamazepine, phenytoin, St. John's wort, rifampin, other antipsychotics, antibiotics, antiarrhythmics, pentamidine, levomethadyl acetate, methadone, halofantrine, mefloquine, dolasetron mesylate, probucol, tacrolimus, antidepressants, and phenothiazines. Tell your doctor all medications and supplements you use. During pregnancy, Versacloz should be used only if prescribed. This drug passes into breast milk. Consult your doctor before breastfeeding.
Our Versacloz (clozapine) Oral Suspension Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Versacloz FDA Prescribing Information: Side Effects
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
(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
Myasthenic syndrome and rhabdomyolysis.
Hemic and Lymphatic System
Read the entire FDA prescribing information for Versacloz (Clozapine Oral Suspension) »
Additional Versacloz Information
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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