What the FDA labels say about taking them together
Clozapine and duloxetine
Clozapine's FDA label of June 6, 2025 names duloxetine in its drug interactions section; the duloxetine labels PlainMeds reads (2) do not name clozapine. The clozapine label: “CYP2D6 and CYP3A4 Inhibitors Concomitant treatment with CLOZARIL and CYP2D6 or CYP3A4 inhibitors can increase clozapine levels and lead to adverse reactions.”
Check it at the source: the clozapine FDA label on DailyMed (effective June 6, 2025, HLS Therapeutics (USA), Inc.); the duloxetine FDA label on DailyMed (effective May 14, 2024, SUN PHARMACEUTICAL INDUSTRIES, INC.).
What does the clozapine label say about duloxetine?
Clozapine label, drug interactionsCYP2D6 and CYP3A4 Inhibitors Concomitant treatment with CLOZARIL and CYP2D6 or CYP3A4 inhibitors (e.g., cimetidine, escitalopram, erythromycin, paroxetine, bupropion, fluoxetine, quinidine, duloxetine, terbinafine, or sertraline) can increase clozapine levels and lead to adverse reactions [see Clinical Pharmacology ( 12.3 )].
Source: FDA drug label (Versacloz, NDA203479), TruPharma LLC, effective September 6, 2026 (SPL set 2592c9a8-fd74-4e0d-a895-b07b014cf355), via openFDA
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 duloxetine label say about clozapine?
Duloxetine's label (effective May 14, 2024) and its 1 other brand-application label do 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 (DRIZALMA SPRINKLE), SUN PHARMACEUTICAL INDUSTRIES, INC., effective May 14, 2024 (SPL set b41423b8-dfec-4d79-ba3c-e43a87803d85), 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 | Duloxetine | |
|---|---|---|
| Labeled for | Schizophrenia | Depression, Anxiety, Nerve pain and fibromyalgia, Pain |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.610 per tablet 100 mg tablet | $0.102 per capsule 30 mg capsule |
| 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