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Clozaril

clozapine · Tablet

Prescription NDA TE AB RLD Official labelling
Informational index, not medical advice. Content is reproduced from public FDA and NLM data. Always confirm against the manufacturer's current prescribing information. Report adverse events to FDA MedWatch.

Overview

Brand name
Clozaril
Generic name
clozapine
Dosage form
Tablet
Route
Oral
Marketing category
NDA · NDA
Labeler
HLS Therapeutics (USA), Inc.
Product type
Human Prescription Drug
DEA schedule
Not scheduled
Active ingredients
2
NDC product codes
2
Packages
2
Data completeness
76% of corroborating sources present

Active ingredients

Source: NDC Directory
Active ingredients and strengths as listed in the NDC Directory.
Ingredient Strength RxCUI Monograph
Clozapine 100 mg/1 197535 View
Clozapine 25 mg/1 197535 View

Forms, strengths and routes

Source: NDC Directory
Dosage form
Tablet
Route of administration
Oral
Presentations
4

Pharmacologic classes are listed in the class section below.

Pharmacologic class

Source: NDC Directory
Established pharmacologic classes (EPC), mechanisms of action (MoA), chemical structures (CS) and physiologic effects (PE).
Class Type Browse
Atypical Antipsychotic [EPC] EPC All 62 members

Regulatory status

Source: Drugs@FDANDC Directory
Application number
019758
Application type
NDA · New Drug Application
Approval date
September 26, 1989
Sponsor
HERITAGE LIFE
Products on application
4
Submissions recorded
84
Products approved under application 019758.
Product Trade name Form Strength Ingredient Status TE Flags
019758-001 CLOZARIL TABLET CLOZAPINE Prescription AB RLD
019758-002 CLOZARIL TABLET CLOZAPINE Prescription AB RLD RS
019758-003 CLOZARIL TABLET CLOZAPINE Discontinued AB RLD
019758-004 CLOZARIL TABLET CLOZAPINE Discontinued AB RLD

Therapeutic equivalence

Source: Orange Book
TE code
AB
Reference Listed Drug
Yes
Reference Standard
Yes

What this rating means: Therapeutically equivalent — bioequivalence demonstrated by in vivo or in vitro testing

Codes beginning with “A” indicate products the FDA considers therapeutically equivalent. Codes beginning with “B” indicate bioequivalence has not been established. See methodology.

Approval history

Source: Drugs@FDA
Most recent submissions on application 019758.
Type No. Action Status Date Review
Supplement 107 REMS Approved June 13, 2025 N/A
Supplement 106 Labeling Approved January 22, 2025 Standard
Supplement 104 Labeling Approved September 12, 2024 Standard
Supplement 103 Labeling Approved May 19, 2023 Standard
Supplement 101 Labeling Approved December 19, 2022 Standard
Supplement 99 REMS Approved November 10, 2021 N/A
Supplement 98 REMS Approved July 29, 2021 N/A
Supplement 96 REMS Approved February 18, 2021 N/A
Supplement 88 Labeling Approved February 11, 2021 Standard
Supplement 95 Labeling Approved April 14, 2020 901 Required
Supplement 90 REMS Approved January 16, 2019 N/A
Supplement 84 Labeling Approved February 23, 2017 901 Required
Supplement 81 Labeling Approved January 26, 2017 Standard
Supplement 80 Labeling Approved December 20, 2016 Standard
Supplement 79 Manufacturing (CMC) Approved May 6, 2016 Priority
Supplement 76 Manufacturing (CMC) Approved November 10, 2015 Priority
Supplement 78 Labeling Approved October 8, 2015 Standard
Supplement 74 Labeling Approved September 18, 2015 Standard
Supplement 77 Labeling Approved September 15, 2015 Standard
Supplement 61 REMS Approved September 15, 2015 N/A
Supplement 73 Labeling Approved December 19, 2014 Standard
Supplement 64 Manufacturing (CMC) Approved September 30, 2014 Priority
Supplement 72 Labeling Approved September 29, 2014 Standard
Supplement 71 Labeling Approved July 19, 2013 Standard
Supplement 69 Labeling Approved July 19, 2013 Standard
Supplement 70 Labeling Approved March 22, 2013 Standard
Supplement 68 Labeling Approved March 22, 2013 Standard
Supplement 67 Labeling Approved March 22, 2013 Standard
Supplement 63 Labeling Approved October 19, 2011 Unknown
Supplement 65 Labeling Approved December 1, 2010 901 Required
Supplement 62 Labeling Approved January 14, 2010 Standard
Supplement 53 Labeling Approved November 6, 2008 Standard
Supplement 59 Labeling Approved August 14, 2008 Standard
Supplement 58 Labeling Approved June 26, 2008 Standard
Supplement 57 Labeling Approved December 5, 2005 Standard
Supplement 56 Labeling Approved June 29, 2005 Standard
Supplement 54 Labeling Approved May 12, 2005 Standard
Supplement 51 Labeling Approved December 23, 2003 Standard
Supplement 47 Efficacy Approved December 18, 2002 Priority
Supplement 48 Labeling Approved July 5, 2002 Standard
Supplement 45 Labeling Approved January 14, 2002 Standard
Supplement 46 Manufacturing (CMC) Approved December 14, 2001 Priority
Supplement 44 Labeling Approved August 29, 2001 Standard
Supplement 43 Manufacturing (CMC) Approved May 18, 2001 Priority
Supplement 42 Manufacturing (CMC) Approved May 17, 2000 Priority
Supplement 41 Labeling Approved March 17, 2000 Standard
Supplement 39 Manufacturing (CMC) Approved November 1, 1999 Priority
Supplement 40 Manufacturing (CMC) Approved October 15, 1999 Priority
Supplement 37 Manufacturing (CMC) Approved August 9, 1999 Priority
Supplement 38 Manufacturing (CMC) Approved April 15, 1999 Priority
Supplement 36 Labeling Approved August 19, 1998 Standard
Supplement 34 Labeling Approved March 3, 1998 Standard
Supplement 35 Labeling Approved September 19, 1997 Standard
Supplement 32 Labeling Approved June 27, 1997 Standard
Supplement 33 Labeling Approved April 25, 1997 Standard
Supplement 27 Labeling Approved April 25, 1997 Standard
Supplement 25 Labeling Approved April 25, 1997 Standard
Supplement 23 Labeling Approved April 25, 1997 Standard
Supplement 31 Manufacturing (CMC) Approved January 13, 1997 Priority
Supplement 30 Manufacturing (CMC) Approved May 7, 1996 Priority

Review documents

  • 0 · Supplement · May 4, 2026
  • 0 · Supplement · June 16, 2025
  • 0 · Supplement · June 16, 2025
  • 0 · Supplement · February 7, 2025
  • 0 · Supplement · February 4, 2025
  • 0 · Supplement · January 15, 2025
  • 0 · Supplement · January 15, 2025
  • 0 · Supplement · January 15, 2025
  • 0 · Supplement · September 16, 2024
  • 0 · Supplement · September 16, 2024
  • 0 · Supplement · October 25, 2023
  • 0 · Supplement · October 2, 2023
  • 0 · Supplement · October 2, 2023
  • 0 · Supplement · May 31, 2023
  • 0 · Supplement · December 21, 2022
  • 0 · Supplement · December 21, 2022
  • 0 · Supplement · November 24, 2021
  • 0 · Supplement · August 2, 2021
  • 0 · Supplement · February 22, 2021
  • 0 · Supplement · February 16, 2021
  • 0 · Supplement · February 16, 2021
  • 0 · Supplement · April 15, 2020
  • 0 · Supplement · April 15, 2020
  • 0 · Supplement · January 22, 2019
  • 0 · Supplement · March 2, 2017
  • 0 · Supplement · February 27, 2017
  • 0 · Supplement · January 30, 2017
  • 0 · Supplement · January 26, 2017
  • 0 · Supplement · December 22, 2016
  • 0 · Supplement · December 21, 2016

Prescribing information

Source: openFDA Drug Labeling

Reproduced verbatim from the Structured Product Labeling submitted to the FDA (effective 20250606). This is the manufacturer's labelling text, not a summary and not advice.

HUMAN PRESCRIPTION DRUG · 20250606

Boxed Warning

openFDA Drug Labeling

WARNING: SEVERE NEUTROPENIA; ORTHOSTATIC HYPOTENSION, BRADYCARDIA, AND SYNCOPE; SEIZURE; MYOCARDITIS, PERICARDITIS AND CARDIOMYOPATHY; INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS Severe Neutropenia CLOZARIL has caused severe neutropenia which is associated with an increased risk of serious and potentially fatal infections. Prior to initiating CLOZARIL treatment, obtain baseline ANC(s). CLOZARIL initiation is not recommended in patients with a baseline ANC less than 1500/μL (less than 1000/μL for those with Benign Ethnic Neutropenia (also known as Duffy-null associated neutrophil count)). See recommendations for dosage modifications based on ANC levels during CLOZARIL treatment [see Dosage and Administration ( 2.3 , 2.4 )] . Consider a hematology consultation before initiating CLOZARIL or during CLOZARIL treatment [see Warnings and Precautions ( 5.1 )] . Orthostatic Hypotension, Bradycardia, Syncope Orthostatic hypotension, bradycardia, syncope, and cardiac arrest have occurred with CLOZARIL 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, or when restarting patients who have had even a brief interruption in treatment with CLOZARIL. Initiate treatment at 12.5 mg once or twice daily; titrate slowly; and use divided dosages to minimize risk. Use CLOZARIL 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 , 2.6 ), Warnings and Precautions ( 5.2 )]. Seizures Seizures have occurred with CLOZARIL treatment. The risk is dose-related. Initiate treatment at 12.5 mg, titrate gradually, and use divided dosing. Use caution when administering CLOZARIL 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 ( 2.2 ), Warnings and Precautions ( 5.4 )]. Myocarditis, Pericarditis, Cardiomyopathy and Mitral Valve Incompetence Fatal myocarditis and cardiomyopathy have occurred with CLOZARIL treatment. Discontinue CLOZARIL and obtain a cardiac evaluation upon suspicion of these reactions. Generally, patients with CLOZARIL-related myocarditis or cardiomyopathy should not be rechallenged with CLOZARIL. Consider the possibility of myocarditis, pericarditis, or cardiomyopathy if chest pain, tachycardia, palpitations, dyspnea, fever, flu-like symptoms, hypotension, or ECG changes occur [see Warnings and Precautions( 5.5 )] . 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. CLOZARIL is not approved for use in patients with dementia-related psychosis [see Warnings and Precautions ( 5.6 )]. WARNING: SEVERE NEUTROPENIA; ORTHOSTATIC HYPOTENSION, BRADYCARDIA, AND SYNCOPE; SEIZURE; MYOCARDITIS, PERICARDITIS AND CARDIOMYOPATHY; INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS See full prescribing information for complete boxed warning. • Severe Neutropenia: CLOZARIL has caused severe neutropenia, which is associated with an increased risk of serious and fatal infections. Prior to initiating CLOZARIL treatment, obtain baseline ANC(s). CLOZARIL initiation is not recommended in patients with a baseline ANC less than 1500/ μ L (less than 1000 μ L for those with Benign Ethnic Neutropenia (also known as Duffy-null associated neutrophil count)). See recommendations for dosage modifications based on ANC levels during CLOZARIL treatment ( 2.3 , 2.4 , 5.1 ) • Orthostatic Hypotension, Bradycardia, and Syncope: Risk is dose-r …

Recent Major Changes

openFDA Drug Labeling

Boxed Warning Dosage and Administration ( 2 ) Warnings and Precautions ( 5.1 ) 6/2025 6/2025 6/2025 Warnings and Precautions ( 5.5 ) 1/2025

Indications and Usage

openFDA Drug Labeling

1 INDICATIONS AND USAGE CLOZARIL is an atypical antipsychotic indicated for: • Treatment of severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment. Because of the risks of severe neutropenia and of seizure associated with its use, CLOZARIL should be used only in patients who have failed to respond adequately to standard antipsychotic treatment ( 1.1 ) • Reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder who are judged to be at chronic risk for re-experiencing suicidal behavior. ( 1.2 ) 1.1 Treatment-Resistant Schizophrenia CLOZARIL is indicated for the treatment of severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment. Because of the risks of severe neutropenia and of seizure associated with its use, CLOZARIL should be used only in patients who have failed to respond adequately to standard antipsychotic treatment [see Warnings and Precautions ( 5.1 , 5.4 )]. The effectiveness of CLOZARIL in treatment-resistant schizophrenia was demonstrated in a 6-week, randomized, double-blind, active-controlled study comparing CLOZARIL and chlorpromazine in patients who had failed other antipsychotics [see Clinical Studies ( 14.1 )] . 1.2 Reduction in the Risk of Recurrent Suicidal Behavior in Schizophrenia or Schizoaffective Disorder CLOZARIL is indicated for reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder who are judged to be at chronic risk for re-experiencing suicidal behavior, based on history and recent clinical state. Suicidal behavior refers to actions by a patient that put him/herself at risk for death. The effectiveness of CLOZARIL in reducing the risk of recurrent suicidal behavior was demonstrated over a two-year treatment period in the InterSePTTM trial [see Clinical Studies ( 14.2 )] .

1.1 Treatment-Resistant Schizophrenia CLOZARIL is indicated for the treatment of severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment. Because of the risks of severe neutropenia and of seizure associated with its use, CLOZARIL should be used only in patients who have failed to respond adequately to standard antipsychotic treatment [see Warnings and Precautions ( 5.1 , 5.4 )]. The effectiveness of CLOZARIL in treatment-resistant schizophrenia was demonstrated in a 6-week, randomized, double-blind, active-controlled study comparing CLOZARIL and chlorpromazine in patients who had failed other antipsychotics [see Clinical Studies ( 14.1 )] .

1.2 Reduction in the Risk of Recurrent Suicidal Behavior in Schizophrenia or Schizoaffective Disorder CLOZARIL is indicated for reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder who are judged to be at chronic risk for re-experiencing suicidal behavior, based on history and recent clinical state. Suicidal behavior refers to actions by a patient that put him/herself at risk for death. The effectiveness of CLOZARIL in reducing the risk of recurrent suicidal behavior was demonstrated over a two-year treatment period in the InterSePTTM trial [see Clinical Studies ( 14.2 )] .

Dosage and Administration

openFDA Drug Labeling

2 DOSAGE AND ADMINISTRATION • Recommended starting oral dosage is 12.5 mg once daily or twice daily. ( 2.2 ) • If well-tolerated, increase the total daily dosage in increments of 25 mg to 50 mg per day to achieve a target dosage of 150 mg to 225 mg twice per day by the end of two weeks. ( 2.2 ) • Subsequently may increase the dosage in increments up to 100 mg once or twice weekly ( 2.2 ) • Maximum daily dosage is 450 mg twice daily. ( 2.2 ) • Administer with or without food. ( 2.2 ) • See the dosage modifications based on ANC results and recommended frequency of ANC testing in the full prescribing information. ( 2.3 , 2.4 ) • See recommendations for discontinuing CLOZARIL treatment ( 2.5 ), restarting CLOZARIL after interrupting dosing ( 2.6 ), dosage modifications for drug interactions( 2.7 ), dosage recommendations in patients with renal or hepatic impairment and CYP2D6 poor metabolizers ( 2.8 ) in the full prescribing information. 2.1 Absolute Neutrophil Count Testing Prior to CLOZARIL Initiation Prior to initiating CLOZARIL treatment, obtain a baseline absolute neutrophil count (ANC). CLOZARIL initiation is not recommended in patients with an ANC less than 1500/μL [see Warnings and Precautions ( 5.1 )] . For patients with documented Benign Ethnic Neutropenia (BEN) (also known as Duffy-null associated neutrophil count), obtain at least two baseline ANC levels. CLOZARIL initiation is not recommended in patients with BEN with an ANC less than 1000/μL [see Warnings and Precautions ( 5.1 )] . For dosage modifications based on ANC results, see Dosage and Administration ( 2.3 , 2.4 ). 2.2 Recommended Dosage and Administration To reduce the risk of orthostatic hypotension, bradycardia, and syncope, the recommended starting dosage is much lower than the target dosage [see Warnings and Precautions ( 5.2 )] . CLOZARIL can be taken with or without food [see Clinical Pharmacology ( 12.3 )]. The recommended starting oral dosage of CLOZARIL is 12.5 mg once or twice daily. If well-tolerated, increase the total daily dose in increments of 25 mg to 50 mg per day to achieve a target dosage of 150 mg to 225 mg twice per day by the end of two weeks. Subsequently, may increase the dosage in increments of up to 100 mg once weekly or twice weekly. The maximum recommended CLOZARIL oral dosage is 450 mg twice daily. 2.3 Dosage Modifications Based on ANC Results Table 1 provides recommended CLOZARIL dosage modifications based on ANC results [see Warnings and Precautions ( 5.1 )]. For dosage modifications based on ANC results for patients with Benign Ethnic Neutropenia (BEN) (also known as Duffy-null associated neutrophil count), see Table 2 [see Dosage and Administration ( 2.4 )]. Table 1. CLOZARIL Dosage Modifications Based on ANC Results and Frequency of ANC Testing Recommended Dosage Modification Recommended Frequency of ANC Testing During CLOZARIL Treatment ANC Within Normal Range (≥ 1500/μL) No dosage modification; continue treatment • Day 1 to Month 6: Weekly • Month 7 to Month 12: Every 2 weeks • Month 13 and thereafter: Every month If CLOZARIL treatment is reinitiated after a dosage interruption (e.g., patient had neutropenia which required dosage interruption and now has a normal ANC level) for: • < 30 days, continue the previous ANC testing frequency • ≥ 30 days, obtain ANC tests according to the frequency for patients who initiate treatment Mild Neutropenia (ANC between 1000 to 1499/μL) Confirm all initial reports of ANC less than 1500/μL with a repeat ANC measurement within 24 hours. No dosage modification; continue treatment • Three times weekly • Once ANC ≥ 1500/μL, recommend returning to the patient’s last Normal Range ANC testing frequency Moderate Neutropenia (ANC between 500 to 999/μL) • Interrupt treatment and recommend hematology consultation • Resume treatment once ANC ≥1000/μL • Daily • Once ANC ≥ 1000/μL, three times weekly • Once ANC ≥ 1500/μL, test weekly for 4 weeks. If ANC ≥ 1500/μL after monitoring weekly for 4 weeks, ret …

Dosage Forms and Strengths

openFDA Drug Labeling

3 DOSAGE FORMS AND STRENGTHS Tablets: 25 mg and 100 mg round, pale-yellow, with a facilitated score on one side. 25 mg and 100 mg tablets with a facilitated score on one side ( 3 )

Contraindications

openFDA Drug Labeling

4 CONTRAINDICATIONS CLOZARIL is contraindicated in patients with a history of hypersensitivity to clozapine (e.g., photosensitivity, vasculitis, erythema multiforme, or Stevens-Johnson syndrome) or any other component of CLOZARIL [see Adverse Reactions ( 6.2 )]. Known hypersensitivity to clozapine or any other component of CLOZARIL. ( 4 )

Warnings and Cautions

openFDA Drug Labeling

5 WARNINGS AND PRECAUTIONS • Severe neutropenia : See Boxed Warnings ( 5.1 ) • Gastrointestinal Hypomotility with Severe Complications : Severe gastrointestinal adverse reactions have occurred with the use of CLOZARIL. If constipation is identified, close monitoring and prompt treatment is advised. ( 5.7 ) • Eosinophilia : Assess for organ involvement (e.g., myocarditis, pancreatitis, hepatitis, colitis, nephritis). Discontinue if these occur. ( 5.8 ) • QT Interval Prolongation : Can be fatal. Consider additional risk factors for prolonged QT interval (disorders and drugs). ( 5.9 ) • Metabolic Changes : Atypical antipsychotic drugs have been associated with metabolic changes that may increase cardiovascular/cerebrovascular risk. These metabolic changes include: 1. Hyperglycemia and Diabetes Mellitus : Monitor for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Monitor glucose regularly in patients with diabetes or at risk for diabetes. ( 5.10 ) 2. Dyslipidemia : Undesirable alterations in lipids have occurred in patients treated with atypical antipsychotics. ( 5.10 ) 3. Weight Gain : Significant weight gain has occurred. Monitor weight gain. ( 5.10 ) • Neuroleptic Malignant Syndrome (NMS) : Immediately discontinue and monitor closely. Assess for co-morbid conditions. ( 5.11 ) • Hepatotoxicity : Can be fatal. Monitor for hepatotoxicity. Discontinue treatment if hepatitis or transaminase elevations combined with other symptoms occur ( 5.12 ). • Fever : Evaluate for infection and for neutropenia, NMS. ( 5.13 ) • Pulmonary Embolism (PE) : Consider PE if respiratory distress, chest pain, or deep-vein thrombosis occur. ( 5.14 ) • Anticholinergic Toxicity : When possible, avoid use with other anticholinergic drugs and 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. ( 5.15 , 7.1 ) • Interference with Cognitive and Motor Performance : Advise caution when operating machinery, including automobiles. ( 5.16 ) 5.1 Severe Neutropenia CLOZARIL has caused severe neutropenia (absolute neutrophil count (ANC) less than 500/μL) [see Adverse Reactions ( 6.1 , 6.2 )] and is associated with an increased risk of serious and potentially fatal infections. Severe neutropenia occurred in a small percentage of CLOZARIL-treated patients. The risk of severe neutropenia appears greatest during the first 18 weeks of CLOZARIL treatment. The mechanism by which CLOZARIL causes neutropenia is unknown. Neutropenia is not dose dependent. Consider a hematology consultation before initiating CLOZARIL treatment or during treatment. ANC Monitoring and Dosage Modifications Prior to initiating CLOZARIL treatment, obtain a baseline ANC. CLOZARIL initiation is not recommended in patients with a baseline ANC less than 1500/μL. Throughout CLOZARIL treatment, regularly monitor ANC. Table 1 provides recommendations for dosage modifications (dosage interruption and treatment discontinuation), based on ANC levels, during CLOZARIL treatment and frequency of ANC monitoring [see Dosage and Administration ( 2.3 )]. ANC Monitoring and Dosage Modification in Patients with Benign Ethnic Neutropenia Patients with Benign Ethnic Neutropenia (BEN) (also known as Duffy-null associated neutrophil count) generally have lower baseline neutrophil counts but they are not at higher risk for developing infections, and they are not at increased risk for developing CLOZARIL-induced neutropenia. For patients with documented BEN, obtain at least two baseline ANC levels prior to CLOZARIL initiation. CLOZARIL initiation is not recommended in patients with BEN with an ANC less than 1000/μL. There are different ANC dosage modification recommendations in CLOZARIL-treated patients with BEN due to their lower baseline ANC levels. Table 2 provides recommendations on dosage mod …

Adverse Reactions

openFDA Drug Labeling

6 ADVERSE REACTIONS The following adverse reactions are discussed in more detail in other sections of the labeling: • Severe Neutropenia [see Warnings and Precautions ( 5.1 )] • Orthostatic Hypotension, Bradycardia, and Syncope [see Warnings and Precautions ( 5.2 )] • Falls [see Warnings and Precautions ( 5.3 )] • Seizures [see Warnings and Precautions ( 5.4 )] • Myocarditis, Pericarditis, Cardiomyopathy, and Mitral Valve Incompetence [see Warnings and Precautions ( 5.5 )] • Increased Mortality in Elderly Patients with Dementia-Related Psychosis [see Warnings and Precautions ( 5.6 )] • Gastrointestinal Hypomotility with Severe Complications [See Warnings and Precautions ( 5.7) ] • Eosinophilia [see Warnings and Precautions ( 5.8 )] • QT Interval Prolongation [see Warnings and Precautions ( 5.9 )] • Metabolic Changes (Hyperglycemia and Diabetes Mellitus, Dyslipidemia, and Weight Gain) [see Warnings and Precautions ( 5.10 )] • Neuroleptic Malignant Syndrome [see Warnings and Precautions ( 5.11 )] • Hepatotoxicity [see Warnings and Precautions ( 5.12 )] • Fever [see Warnings and Precautions ( 5.13 )] • Pulmonary Embolism [see Warnings and Precautions ( 5.14 )] • Anticholinergic Toxicity [see Warnings and Precautions ( 5.15 )] • Interference with Cognitive and Motor Performance [see Warnings and Precautions ( 5.16 )] • Tardive Dyskinesia [see Warnings and Precautions ( 5.17 )] • Cerebrovascular Adverse Reactions [see Warnings and Precautions ( 5.18 )] • Recurrence of Psychosis and Cholinergic Rebound after Abrupt Discontinuation [see Warnings and Precautions ( 5.19 )] Most common adverse reactions (≥5%) were: CNS reactions (sedation, dizziness/vertigo, headache, and tremor); cardiovascular reactions (tachycardia, hypotension, and syncope); autonomic nervous system reactions (hypersalivation, sweating, dry mouth, and visual disturbances); gastrointestinal reactions (constipation and nausea); and fever. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact HLS Therapeutics (USA), Inc. at (844) 457-8721 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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 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 InterSePTTM 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 InterSePTTM Study) †Rate based on population of approximately 1700 exposed during premarket clinical evaluation of CLOZARIL. Body System Adverse Reaction * CLOZARIL N=842 Percentage of Patients C …

Drug Interactions

openFDA Drug Labeling

7 DRUG INTERACTIONS • Concomitant use of Strong CYP1A2 Inhibitors: Reduce CLOZARIL dose to one-third when coadministered with strong CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin, enoxacin). ( 2.7 , 7.1 ) • Concomitant use of Strong CYP3A4 Inducers is not recommended. ( 2.7 , 7.1 ) • Discontinuation of CYP1A2 or CYP3A4 Inducers: Consider reducing CLOZARIL dose when CYP1A2 inducers (e.g., tobacco smoke) or CYP3A4 inducers (e.g., carbamazepine) are discontinued. ( 2.7 , 7.1 ) • Anticholinergic drugs: Concomitant use may increase the risk for anticholinergic toxicity. ( 5.7 , 5.15 , 7.1 ) 7.1 Potential for Other Drugs to Affect CLOZARIL 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. CYP1A2 Inhibitors 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 ( 2.7 ), 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 ( 2.7 )] . CYP2D6 and CYP3A4 Inhibitors 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 ( 2.7 )] . CYP1A2 and CYP3A4 Inducers 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 ( 2.7 )] . 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 ( 2.7 )] . Anticholinergic Drugs 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 ( 5.7 , 5.15 )] . Drugs that Cause QT Interval Prolongation 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) …

Use in Specific Populations

openFDA Drug Labeling

8 USE IN SPECIFIC POPULATIONS • Pregnancy: May cause extrapyramidal and/or withdrawal symptoms in neonates with third trimester exposure ( 8.1 ). 8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to atypical antipsychotics, including CLOZARIL, during pregnancy. Healthcare providers are encouraged to advise patients to register by calling the National Pregnancy Registry for Atypical Antipsychotics at1-866-961-2388 or visiting http://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/ . Risk Summary Neonates exposed to antipsychotic drugs, including CLOZARIL, during the third trimester are at risk for extrapyramidal and/or withdrawal symptoms following delivery ( see Clinical Considerations ). Available data from published epidemiologic studies over decades of use with clozapine during pregnancy have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes ( see Data ). There are risks to the mother associated with untreated schizophrenia and with exposure to antipsychotics, including CLOZARIL, during pregnancy ( see Clinical Considerations ). In animal reproduction studies, no adverse developmental effects were observed when clozapine was administered orally to pregnant rats or rabbits during the period of organogenesis, or to pregnant rats during pregnancy and lactation, at doses up to approximately 0.4 and 0.9 times the maximum recommended human dose (MRHD) of 900 mg/day, for rats and rabbits respectively, based on mg/m2 body surface area ( see Data ). The background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defects, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Disease-associated maternal and/or embryo/fetal risk There is a risk to the mother from untreated schizophrenia, including increased risk of relapse, hospitalization, and suicide. Schizophrenia is associated with increased adverse perinatal outcomes, including preterm birth. It is not known if this is a direct result of the illness or other comorbid factors. Fetal/Neonatal adverse reactions Extrapyramidal and/or withdrawal symptoms, including agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorder have been reported in neonates who have been exposed to antipsychotic drugs, including CLOZARIL, during the third trimester of pregnancy. These symptoms have varied in severity. Monitor neonates for extrapyramidal and/or withdrawal symptoms and manage symptoms appropriately. Some neonates recovered within hours or days without specific treatment; others required prolonged hospitalization. Data 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/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. 8.2 Lactation Risk Summary Clozapine is present in human milk. There is one case report of sedation and a report of agranulocytosis in an infant exposed to clozapine through human milk ( see …

Mechanism of Action

openFDA Drug Labeling

12.1 Mechanism of Action The mechanism of action of clozapine is unknown. However, it has been proposed that the therapeutic efficacy of clozapine in schizophrenia is mediated through antagonism of the dopamine type 2 (D 2 ) and the serotonin type 2A (5-HT 2A ) receptors. CLOZARIL also acts as an antagonist at adrenergic, cholinergic, histaminergic and other dopaminergic and serotonergic receptors.

Description

openFDA Drug Labeling

11 DESCRIPTION CLOZARIL ® (clozapine), an atypical antipsychotic drug, is a tricyclic dibenzodiazepine derivative, 8-chloro-11-(4-methyl-1-piperazinyl)-5 H -dibenzo [ b,e ] [1,4] diazepine. The structural formula is: CLOZARIL is available in pale yellow tablets of 25 mg and 100 mg for oral administration. Active Ingredient: clozapine Inactive Ingredients are colloidal silicon dioxide, lactose, magnesium stearate, povidone, starch (corn), and talc. structural formula

10 OVERDOSAGE 10.1 Overdosage Experience The most commonly reported signs and symptoms associated with clozapine overdose are: sedation, delirium, coma, tachycardia, hypotension, respiratory depression or failure; and hypersalivation. There are reports of aspiration pneumonia, cardiac arrhythmias, and seizure. Fatal overdoses have been reported with clozapine, generally at doses above 2500 mg. There have also been reports of patients recovering from overdoses well in excess of 4 g. 10.2 Management of Overdosage There is no available specific antidote to an overdose of CLOZARIL. Establish and maintain an airway; ensure adequate oxygenation and ventilation. Monitor cardiac status and vital signs. Use general symptomatic and supportive measures. Consider the possibility of multiple-drug involvement. Contact a Certified Poison Control Center for the most up to date information on the management of overdosage (1-800-222-1222).

10.1 Overdosage Experience The most commonly reported signs and symptoms associated with clozapine overdose are: sedation, delirium, coma, tachycardia, hypotension, respiratory depression or failure; and hypersalivation. There are reports of aspiration pneumonia, cardiac arrhythmias, and seizure. Fatal overdoses have been reported with clozapine, generally at doses above 2500 mg. There have also been reports of patients recovering from overdoses well in excess of 4 g.

10.2 Management of Overdosage There is no available specific antidote to an overdose of CLOZARIL. Establish and maintain an airway; ensure adequate oxygenation and ventilation. Monitor cardiac status and vital signs. Use general symptomatic and supportive measures. Consider the possibility of multiple-drug involvement. Contact a Certified Poison Control Center for the most up to date information on the management of overdosage (1-800-222-1222).

How Supplied / Storage and Handling

openFDA Drug Labeling

16 HOW SUPPLIED/STORAGE AND HANDLING 16.1 How Supplied CLOZARIL ® (clozapine) Tablets 25 mg Round, pale-yellow, uncoated tablet. Debossed with “CLOZARIL” once on the periphery of one side. Debossed with a facilitated score and “25” once on the other side. Bottle of 100 NDC 69809-0126-05 100 mg Round, pale-yellow, uncoated tablet. Debossed with “CLOZARIL” once on the periphery of one side. Debossed with a facilitated score and “100” once on the other side. Bottle of 100 NDC 69809-0127-05 16.2 Storage and Handling Store CLOZARIL at room temperature between 20°C to 25°C (68°F to 77°F); excursion permitted between 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature].

16.1 How Supplied CLOZARIL ® (clozapine) Tablets 25 mg Round, pale-yellow, uncoated tablet. Debossed with “CLOZARIL” once on the periphery of one side. Debossed with a facilitated score and “25” once on the other side. Bottle of 100 NDC 69809-0126-05 100 mg Round, pale-yellow, uncoated tablet. Debossed with “CLOZARIL” once on the periphery of one side. Debossed with a facilitated score and “100” once on the other side. Bottle of 100 NDC 69809-0127-05

Adverse event reports

Source: openFDA FAERS
124,828
FAERS reports mentioning this drug
as of 2026-09-25T03:42:24+00:00
A report count is not a risk measure. FAERS accepts voluntary and mandatory reports without establishing causation, and reporting is influenced by how widely a drug is used, how long it has been marketed, and media attention. FDA states that reports “do not prove that the drug caused the event”. Compare rates, not totals.

Attributed to this product's most-reported active ingredient: CLOZAPINE. Combination products with more than six active ingredients are not attributed, because a report count summed across a long ingredient list measures the list, not the medicine.

Packaging and NDCs

Source: NDC Directory
Every National Drug Code package associated with this medication. The NDC is the identifier used for dispensing, billing and pharmacovigilance in the United States.
Package NDC Product NDC Labeler Description Marketing start
69809-0126-5 69809-0126 HLS Therapeutics (USA), Inc. 100 TABLET in 1 BOTTLE (69809-0126-5) May 6, 2016
69809-0127-5 69809-0127 HLS Therapeutics (USA), Inc. 100 TABLET in 1 BOTTLE (69809-0127-5) May 6, 2016
69809-0126 69809-0126 HLS Therapeutics (USA), Inc. — May 6, 2016
69809-0127 69809-0127 HLS Therapeutics (USA), Inc. — May 6, 2016

Sources for this page

Every dataset that contributed a fact to this page.
Dataset Agency Used for
NDC Directory FDA Identity, ingredients, strengths, forms, routes, labelers, packages
Drugs@FDA FDA Application, sponsor, submissions, review documents, marketing status
Orange Book FDA Therapeutic equivalence codes, reference drug flags, patents, exclusivity
Drug Labeling FDA / NLM Prescribing information reproduced above
FAERS FDA Adverse event report counts

Generated September 25, 2026 · 11 sections on this page.