Clozapine
According to the FDA label: Clozapine tablets are 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, clozapine tablets should be used only in patients who have failed to respond adequately to standard antipsychotic treatment.
75,271 adverse event reports submitted to the FDA (2003–2026)
Top Reported Adverse Events
The most frequently reported events in association with Clozapine in the FAERS database. These are events reported by patients taking this medication, not necessarily caused by it. A single report may include multiple events.
Show these terms with plain-language definitions
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Neutropenia 16,482 reports
A low level of neutrophils, a type of white blood cell that fights infection.
Full definition in the glossary →Hospitalisation 7,671 reports
A report that the person was admitted to a hospital. This records that a hospital stay occurred, which is one way the seriousness of an event is tracked. Also spelled hospitalization in American English.
Full definition in the glossary →Death 5,201 reports
A report that the person died. A death appearing in reports for a drug does not mean the drug caused it. Reports record that a death occurred while the medication was being used, which can happen for many unrelated reasons.
Full definition in the glossary →Drug Ineffective 3,078 reports
A report that the medication did not work as expected for the person taking it. This is a reporting category, not a sign the drug is defective. It simply means someone felt it was not helping their condition.
Full definition in the glossary →Drug Interaction 2,729 reports
A report that two or more medications may have affected each other when taken together.
Full definition in the glossary →- Granulocytopenia 2,567 reports
Off Label Use 2,074 reports
Using a medication for a condition or in a way that the FDA has not officially approved. This is common and often legal, and a report of it does not mean something went wrong. Doctors sometimes prescribe drugs off label based on their judgment.
Full definition in the glossary →Psychotic Disorder 1,854 reports
A mental health condition involving a loss of contact with reality, which can include hallucinations or delusions. The term records what was reported and does not establish that a medication was the cause.
Full definition in the glossary →Leukopenia 1,727 reports
A low level of white blood cells, which help fight infection. Closely related to neutropenia, which is a low level of one specific type of white blood cell.
Full definition in the glossary →- Neutrophilia 1,673 reports
- Agranulocytosis 1,636 reports
Toxicity to Various Agents 1,570 reports
A broad reporting category used when the body has a harmful response, sometimes involving more than one substance.
Full definition in the glossary →Schizophrenia 1,542 reports
A mental health condition that affects how a person thinks, feels, and perceives reality. It often appears in reports as a condition being treated.
Full definition in the glossary →Somnolence 1,519 reports
Drowsiness or strong sleepiness.
Full definition in the glossary → See all drugs reporting this event →Sedation 1,509 reports
A state of calm, drowsiness, or reduced alertness.
Full definition in the glossary →
Ranked by frequency of reports, not severity. The most-reported event is not necessarily the most dangerous or the most common in patients taking this drug.
Who Is Reporting
Demographics of patients in FAERS reports that included this information. Not all reports include patient demographics.
By Sex
View reporter sex data as a table
| Sex | Reports |
|---|---|
| Male | 37,639 |
| Female | 25,423 |
| Unknown | 115 |
By Age Group
View age group data as a table
| Age group | Reports |
|---|---|
| 0-17 | 1,873 |
| 18-34 | 12,560 |
| 35-49 | 13,770 |
| 50-64 | 14,247 |
| 65-74 | 5,949 |
| 75+ | 3,060 |
This shows who filed reports, reflecting who takes this drug and who tends to report, not who is at greatest risk.
Reported Outcomes
Outcomes recorded in FAERS reports that included Clozapine. A single report may involve multiple reactions, each with a different outcome. These categories are defined by FDA reporting guidelines, not by PillSignal.
View outcome data as a table
| Outcome | Reports |
|---|---|
| Other Serious | 43,971 |
| Hospitalization | 30,216 |
| Death | 10,992 |
| Non-Serious | 5,501 |
| Life-Threatening | 5,261 |
| Disability | 691 |
Serious outcomes are far more likely to be reported than mild ones, so this overstates how often outcomes are serious. A recorded death does not mean the drug caused it.
Report Volume Over Time
Number of FAERS reports received per quarter for Clozapine. Changes in volume may reflect shifts in prescribing rates, media attention, or reporting behavior, not changes in the medication's safety profile.
View report trend as a table
| Year | Reports |
|---|---|
| 2003 | 2 |
| 2004 | 1,168 |
| 2005 | 931 |
| 2006 | 2,034 |
| 2007 | 477 |
| 2008 | 441 |
| 2009 | 531 |
| 2010 | 1,063 |
| 2011 | 3,918 |
| 2012 | 1,657 |
| 2013 | 858 |
| 2014 | 925 |
| 2015 | 1,305 |
| 2016 | 3,399 |
| 2017 | 4,406 |
| 2018 | 3,859 |
| 2019 | 4,505 |
| 2020 | 4,788 |
| 2021 | 4,525 |
| 2022 | 10,808 |
| 2023 | 9,611 |
| 2024 | 8,030 |
| 2025 | 5,035 |
| 2026 (partial) | 995 |
The steep increase around 2004 reflects the FDA's move to electronic submission, not a change in this drug's safety. Trends track reporting volume, not risk.
Medications commonly reported with Clozapine
In FDA adverse event reports that mention Clozapine, these medications appeared most often in the same report.
- Olanzapine (5,847 reports)
- Aripiprazole (4,693 reports)
- Risperidone (4,636 reports)
- Quetiapine (4,603 reports)
- Aripiprazole Orally Disintegrating (3,416 reports)
This reflects co-occurrence in submitted reports, not evidence of drug interaction or combined risk. People often report several medications taken for the same condition or for unrelated reasons. Talk to a doctor or pharmacist about your specific medications.
Related Drugs
Other medications with similar adverse event profiles in FDA FAERS reports.
Data Source
This data is sourced from the FDA's Adverse Event Monitoring System (AEMS), formerly FAERS, via the OpenFDA API. PillSignal is not affiliated with the FDA.
View this data on the FDA website →Data last updated: June 2026