Two medicines, side by side
Clozapine vs olanzapine
Clozapine and olanzapine are both labeled for schizophrenia. Drugs@FDA records approvals of clozapine since 1989 and of olanzapine since 1996. Pharmacies paid $0.610 per clozapine 100 mg tablet and $0.147 per olanzapine 20 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. How each works, in its label's words: Clozapine, “The mechanism of action of clozapine is unknown.”; Olanzapine, “The mechanism of action of olanzapine, in the listed indications is unclear.”
Check it at the source: the clozapine FDA label on DailyMed (effective June 6, 2025); the olanzapine FDA label on DailyMed (effective March 5, 2026).
Highlights of the clozapine record
Clozapine (Clozaril) · label of June 6, 2025
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).
Used for
From the label: indicationsCLOZARIL is an atypical antipsychotic indicated for: • Treatment of severely ill patients with schizophrenia who fail to respond adequately to standard antipsychotic treatment. […]
On the market
- Earliest approval on file
- September 26, 1989
- Generic labelers
- 11 labelers
- Pharmacy cost
- $0.610 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 4
Highlights of the olanzapine record
Olanzapine (Zyprexa) · label of March 5, 2026
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. Analyses of seventeen placebo-controlled trials (modal duration of 10 weeks), largely in patients taking atypical antipsychotic drugs, revealed a risk of death in drug-treated patients of between 1.6 to 1.7 times the risk of death in placebo-treated patients.
Used for
From the label: indicationsOlanzapine is an atypical antipsychotic indicated: As oral formulation for the: · Treatment of schizophrenia. ( 1.1 ) · Adults: Efficacy was established in three clinical trials in patients with schizophrenia: two 6-week trials and one maintenance trial. ( 14.1 ) · Adolescents (ages 13-17): Efficacy was established in one 6-week trial in patients with schizophrenia ( 14.1 ). […]
On the market
- Earliest approval on file
- September 30, 1996
- Generic labelers
- 43 labelers
- Pharmacy cost
- $0.147 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 14
Source: FDA drug labels via openFDA (Clozapine label of June 6, 2025, Olanzapine label of March 5, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do clozapine and olanzapine differ on the record?
How each works, in its label's words: Clozapine, “The mechanism of action of clozapine is unknown.”; Olanzapine, “The mechanism of action of olanzapine, in the listed indications is unclear.”
Both are in FDA's class atypical antipsychotics.
Half-life, in each label's words: Clozapine, “The mean elimination half-life of clozapine after a single 75 mg dose was 8 hours (range: 4 to 12 hours), compared to a …”; Olanzapine, “Its half-life ranges from 21 to 54 hours (5th to 95th percentile; mean of 30 hr), and apparent plasma clearance ranges …”
Both labels carry a boxed warning; the records quote them.
Generics: clozapine since 1996; olanzapine since 2011 (Drugs@FDA).
| Clozapine | Olanzapine | |
|---|---|---|
| Labeled for | Schizophrenia | Schizophrenia, Bipolar disorder, Depression |
| Pharmacologic class | Atypical Antipsychotic | Atypical Antipsychotic |
| How it works (label) | The mechanism of action of clozapine is unknown. | The mechanism of action of olanzapine, in the listed indications is unclear. However, the efficacy of olanzapine in schizophrenia could be mediated through a combination of dopamine and serotonin type 2 (5HT 2 ) antagonism. |
| Half-life (label) | The mean elimination half-life of clozapine after a single 75 mg dose was 8 hours (range: 4 to 12 hours), compared to a mean elimination half-life of 12 hours (range: 4 to 66 hours), after achieving steady state with … | Its half-life ranges from 21 to 54 hours (5th to 95th percentile; mean of 30 hr), and apparent plasma clearance ranges from 12 to 47 L/hr (5th to 95th percentile; mean of 25 L/hr). |
| Earliest approval on file (Drugs@FDA) | September 26, 1989 | September 30, 1996 |
| First generic approved | August 30, 1996 | October 24, 2011 |
| Generic labelers (NDC) | 11 labelers | 43 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.610 per tablet (Clozapine 100 mg tablet) | $0.147 per tablet (Olanzapine 20 mg tablet) |
| 12-month price change | +5% | -5% |
| Boxed warning | Yes | Yes |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 4 | 14 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 124,829 | 107,881 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
Do their labels mention each other?
Clozapine label, warnings and precautionsThe median duration of exposure was 609, 728, and 42 days, in the CLOZARIL, olanzapine, and chlorpromazine group, respectively.
Clozapine label, warnings and precautionsThe median duration of exposure was 609, 728, and 42 days, in the clozapine, olanzapine, and chlorpromazine group, respectively.
Source: FDA drug labels via openFDA
What do the labels say about using others of their kind?
Clozapine label, warnings and precautionsWhen 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.
Source: FDA drug labels via openFDA
What next?
- Alternatives to clozapine
- every medicine labeled for the same conditions