What the FDA labels say about taking them together
Clozapine and mefloquine
Clozapine's FDA label of June 6, 2025 names mefloquine in its drug interactions section; the mefloquine label PlainMeds reads does not name clozapine. 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 clozapine FDA label on DailyMed (effective June 6, 2025, HLS Therapeutics (USA), Inc.); the mefloquine FDA label on DailyMed (effective November 18, 2024, Chartwell RX, LLC).
What does the clozapine label say about mefloquine?
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 )].
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
What does the mefloquine label say about clozapine?
Mefloquine's label (effective November 18, 2024) does not name clozapine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Mefloquine Hydrochloride), Chartwell RX, LLC, effective November 18, 2024 (SPL set b884d22b-aae7-4f14-9a04-ae4029a229f0), 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
| Clozapine | Mefloquine | |
|---|---|---|
| Labeled for | Schizophrenia | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.610 per tablet 100 mg tablet | $3.97 per tablet 250 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