What the FDA labels say about taking them together
Chlorpromazine and clozapine
Clozapine's FDA label of June 6, 2025 names chlorpromazine in its drug interactions section; chlorpromazine's label does not name clozapine itself but warns about its class (Atypical antipsychotics). The clozapine label: “Drugs that cause QT prolongation include: specific antipsychotics, specific antibiotics, Class 1A antiarrhythmics or Class III antiarrhythmics, and others.”
Check it at the source: the chlorpromazine FDA label on DailyMed (effective May 12, 2026, Amneal Pharmaceuticals NY LLC); the clozapine FDA label on DailyMed (effective June 6, 2025, HLS Therapeutics (USA), Inc.).
What does the chlorpromazine label say about clozapine?
Chlorpromazine's label does not name clozapine itself; it warns about its class (Atypical antipsychotics):
Chlorpromazine label, boxed warningAnalyses 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.
Chlorpromazine label, boxed warningWARNING 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.
Source: FDA drug label (CHLORPROMAZINE HYDROCHLORIDE), Amneal Pharmaceuticals NY LLC, effective May 12, 2026 (SPL set aa086a21-de85-4b03-af58-49b70acf8cf0), via openFDA; the full label on DailyMed
What does the clozapine label say about chlorpromazine?
Clozapine label, drug interactionsDrugs 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) [see Warnings and Precautions ( 5.9 )].
Clozapine label, warnings and precautionsLaboratory Parameter: Fasting Glucose; Category Change (at least once) from baseline: Normal (<100 mg/dL) to High (≥126 mg/dL); Treatment Arm: Chlorpromazine; N: 135; n (%): 14 (10)
Source: FDA drug label (Clozaril), NDA019758 (Heritage Life), as published by HLS Therapeutics (USA), Inc., effective June 6, 2025 (SPL set 90876802-0e3a-44c9-9ff7-1754dfbe736a), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Chlorpromazine | Clozapine | |
|---|---|---|
| Labeled for | Schizophrenia, Nausea and vomiting | Schizophrenia |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.552 per tablet 100 mg tablet | $0.610 per tablet 100 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once