What the FDA labels say about taking them together
Clozapine and moxifloxacin
Clozapine's FDA label of June 6, 2025 names moxifloxacin in its drug interactions section; moxifloxacin'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 clozapine FDA label on DailyMed (effective June 6, 2025, HLS Therapeutics (USA), Inc.); the moxifloxacin FDA label on DailyMed (effective March 17, 2026, Macleods Pharmaceuticals Limited).
What does the clozapine label say about moxifloxacin?
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 moxifloxacin label say about clozapine?
Moxifloxacin's label does not name clozapine itself; it warns about its class (Atypical antipsychotics):
Moxifloxacin label, warnings and precautionsKnown prolongation of the QT interval Ventricular arrhythmias including torsade de pointes because QT prolongation may lead to an increased risk for these conditions Ongoing proarrhythmic conditions, such as clinically significant bradycardia and acute myocardial ischemia, Uncorrected hypokalemia or hypomagnesemia Class IA (for example, quinidine, procainamide) or Class III (for example, amiodarone, sotalol) antiarrhythmic agents Other drugs that prolong the QT interval such as cisapride, erythromycin …
Moxifloxacin label, warnings and precautionsPharmacokinetic studies between moxifloxacin and other drugs that prolong the QT interval such as cisapride, erythromycin, antipsychotics, and tricyclic antidepressants have not been performed.
Source: FDA drug label (Moxifloxacin), Macleods Pharmaceuticals Limited, effective March 17, 2026 (SPL set 182ecd0f-714f-42f0-9b16-fb604cf15786), 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 | Moxifloxacin | |
|---|---|---|
| Labeled for | Schizophrenia | Bacterial infections |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.610 per tablet 100 mg tablet | $1.60 per mL 0.5% eye drops |
| Shortage now | No current entry | A presentation being discontinued |
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