CLOZARIL FDA MedWatch Direct Reports Summary

These tables and charts are created from 104 voluntary U.S. reports for CLOZARIL (CLOZAPINE) reported by individuals to the FDA via the MedWatch Reporting System from 2004 through April 28, 2026.

For a summary of adverse events including mandatory reports submitted by pharmaceutical companies (all countries and all reporter types) to the FAERS database, View FDA FAERS CLOZARIL Report.

Top Adverse Effects Associated with CLOZARIL (from U.S. FDA Medwatch Reports)

	Side Effect	# of FDA Reports
1	FALL	9
2	WEIGHT INCREASED	8
3	AGGRESSION	7
4	CONSTIPATION	7
5	SEIZURE	6
6	ABNORMAL BEHAVIOUR	5
7	ANXIETY	5
8	CONFUSIONAL STATE	5
9	DIABETES MELLITUS	5
10	DIARRHEA	5
11	SHORTNESS OF BREATH	5
12	PRODUCT SUBSTITUTION ISSUE	5
13	FEVER	5
14	BLOOD SODIUM DECREASED	4
15	DIZZINESS	4
16	DRUG INEFFECTIVE	4
17	HEADACHE	4
18	HIGH BLOOD PRESSURE	4
19	LOW WHITE BLOOD CELL COUNTS	4
20	OBESITY	4
21	RAPID HEART RATE (TACHYCARDIA)	4
22	TARDIVE DYSKINESIA	4
23	VOMITING	4
24	AGRANULOCYTOSIS	3
25	AKATHISIA	3

Search all MedWatch Reports by Keyword:

CLOZARIL Total Medwatch Safety Reports by Patient Sex

Male	Female	Unknown	Total
60	34	10	104

Medwatch Reporter Type	Count
Consumer	38
Physician	9
Pharmacist	26
Other Health Professional	11

Top Indications

Schizophrenia
Product used for unknown indication
Schizoaffective disorder
Borderline personality disorder
Psychotic disorder

Type of Outcome Reported
Serious: 83
Not Serious: 21
Note: A serious outcome means the adverse event resulted in death, a life threatening condition, hospitalization, disability, congenital anomaly, or other serious condition.

Suspected Role
Primary Suspect: 104
Concomitant Drugs: 46
Note: A single MedWatch report can list more than one drug. This summary includes CLOZARIL identified as the suspect drug or as a concomitantly taken drug.

FDA Safety-Related Labeling Changes

CLOZARIL (CLOZAPINE) Rx Drug:
FDA Safety Communication

Strengthening an existing warning that constipation caused by the schizophrenia medicine clozapine (Clozaril, Fazaclo ODT, Versacloz) can progress to serious bowel problems Drug Safety Communication Drug Safety Communication

CLOZARIL (CLOZAPINE) Rx Drug:
FDA Safety-related Labeling Changes

Added the risk of Pericarditis in addition to myocarditis. Symptoms of myocarditis or percarditis can also include heart palpitations. Added side effect of fecal incontinence.

Have experience (good or bad) with CLOZARIL? Rate CLOZARIL at Ask a Patient.

For serious adverse events, report them to the FDA by contacting the drug manufacturer or report directly through the MedWatch voluntary reporting form.

NOTES

This report, created by AskaPatient.com, is derived from U.S. drug-related adverse event cases that were reported directly to the FDA using the voluntary MedWatch online or paper reporting system. MedWatch is the voluntary FDA system for consumers, physicians, and others to directly report adverse reactions. The Medwatch initiative was launched in 1993 as a voluntary reporting program for consumers, physicians and other healthcare practitioners.

After processing the received forms, the FDA adds the MedWatch reports to the FDA Adverse Events Reporting System(or FAERS database.) Click here for the complete FAERS report summary, which includes mandatory reports submitted by pharmaceutical companies (worldwide) combined with the MedWatch reports. MedWatch Reports only represent about 5% of the FAERS database. For more, read "Does the FDA's Rapidly Growing Database of Adverse Events Improve Drug Safety?"

The data in this report was obtained from Open FDA. Data was last updated to include reports through January 27, 2026. The reactions, side effects, or "adverse events," represent up to the 20 most frequently occuring events in the database for a drug related to the event.

Open FDA states that it only includes the most recent version of a case report. It also adds the disclaimer: "Do not rely on Open FDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated."

FDA uses the "MedDRA" classification system to describe reported adverse reactions. MedDRA is a standardized medical terminology that facilitates sharing of regulatory information internationally. In some cases, "patient friendly" terms for the layman designated by MedDRA have been substituted for medical jargon. Please contact us with questions about this report.