What the FDA labels say about taking them together
Duloxetine and primaquine
Primaquine's FDA label of February 11, 2026 names duloxetine in its drug interactions section; the duloxetine labels PlainMeds reads (2) do not name primaquine. The primaquine label: “Effects of Primaquine on the Pharmacokinetics of Other Drugs CYP1A2 Substrates Published clinical and non-clinical reports indicate primaquine inhibits CYP1A2 enzyme activity and thus may lead to increased exposure of …”
Check it at the source: the duloxetine FDA label on DailyMed (effective May 14, 2024, SUN PHARMACEUTICAL INDUSTRIES, INC.); the primaquine FDA label on DailyMed (effective February 11, 2026, Sanofi-Aventis U.S. LLC).
What does the duloxetine label say about primaquine?
Duloxetine's label (effective May 14, 2024) and its 1 other brand-application label do not name primaquine 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
What does the primaquine label say about duloxetine?
Primaquine label, drug interactionsEffects of Primaquine on the Pharmacokinetics of Other Drugs CYP1A2 Substrates Published clinical and non-clinical reports indicate primaquine inhibits CYP1A2 enzyme activity and thus may lead to increased exposure of CYP1A2 substrate drugs (e.g., duloxetine, alosetron, theophylline and tizanidine) when co-administered with Primaquine phosphate Tablets.
Source: FDA drug label (Primaquine Phosphate), Sanofi-Aventis U.S. LLC, effective February 11, 2026 (SPL set 1bfbf4ae-81b8-4160-a00d-6322aadd4b59), 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
| Duloxetine | Primaquine | |
|---|---|---|
| Labeled for | Depression, Anxiety, Nerve pain and fibromyalgia, Pain | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.102 per capsule 30 mg capsule | n/a |
| 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