Two medicines, side by side
Quetiapine vs clozapine
Quetiapine and clozapine are both labeled for schizophrenia. Drugs@FDA records approvals of quetiapine since 1997 and of clozapine since 1989. Pharmacies paid $0.127 per quetiapine fumarate 300 mg tablet and $0.610 per clozapine 100 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: Quetiapine, “The mechanism of action of quetiapine in the listed indications is unclear.”; Clozapine, “The mechanism of action of clozapine is unknown.”
Check it at the source: the quetiapine FDA label on DailyMed (effective April 10, 2026); the clozapine FDA label on DailyMed (effective June 6, 2025).
Highlights of the quetiapine record
Quetiapine (Seroquel) · label of April 10, 2026
INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS; and SUICIDAL THOUGHTS AND BEHAVIORS 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 [see Warnings and Precautions (5.1) ]. SEROQUEL is not approved for the treatment of patients with dementia-related psychosis [see Warnings and Precautions (5.1) ].
Used for
From the label: indicationsSEROQUEL is an atypical antipsychotic indicated for the treatment of: • Schizophrenia ( 1.1 ) • Bipolar I disorder manic episodes (1.2) • Bipolar disorder, depressive episodes (1.2) 1.1 Schizophrenia SEROQUEL is indicated for the treatment of schizophrenia. The efficacy of SEROQUEL in schizophrenia was established in three 6-week trials in adults and one 6-week trial in adolescents (13-17 years). […]
On the market
- Earliest approval on file
- September 26, 1997
- Generic labelers
- 48 labelers
- Pharmacy cost
- $0.127 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 10
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
Source: FDA drug labels via openFDA (Quetiapine label of April 10, 2026, Clozapine label of June 6, 2025); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do quetiapine and clozapine differ on the record?
How each works, in its label's words: Quetiapine, “The mechanism of action of quetiapine in the listed indications is unclear.”; Clozapine, “The mechanism of action of clozapine is unknown.”
Both are in FDA's class atypical antipsychotics.
Half-life, in each label's words: Quetiapine, “Elimination of quetiapine is mainly via hepatic metabolism with a mean terminal half-life of about 6 hours within the …”; 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 …”
Both labels carry a boxed warning; the records quote them.
Generics: quetiapine since 2012; clozapine since 1996 (Drugs@FDA).
| Quetiapine | Clozapine | |
|---|---|---|
| Labeled for | Schizophrenia, Bipolar disorder, Depression | Schizophrenia |
| Pharmacologic class | Atypical Antipsychotic | Atypical Antipsychotic |
| How it works (label) | The mechanism of action of quetiapine in the listed indications is unclear. However, the efficacy of quetiapine in these indications could be mediated through a combination of dopamine type 2 (D 2 ) and serotonin type 2 (5HT 2 ) antagonism. | The mechanism of action of clozapine is unknown. |
| Half-life (label) | Elimination of quetiapine is mainly via hepatic metabolism with a mean terminal half-life of about 6 hours within the proposed clinical dose range. | 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 … |
| Earliest approval on file (Drugs@FDA) | September 26, 1997 | September 26, 1989 |
| First generic approved | March 27, 2012 | August 30, 1996 |
| Generic labelers (NDC) | 48 labelers | 11 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.127 per tablet (Quetiapine fumarate 300 mg tablet) | $0.610 per tablet (Clozapine 100 mg tablet) |
| 12-month price change | -9% | +5% |
| Boxed warning | Yes | Yes |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 10 | 4 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 191,480 | 124,829 |
| 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)
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 quetiapine
- every medicine labeled for the same conditions