What the FDA labels say about taking them together
Cyproheptadine and fenfluramine
Fenfluramine's FDA label of October 27, 2025 names cyproheptadine in its drug interactions section; the cyproheptadine label PlainMeds reads does not name fenfluramine. The fenfluramine label: “Cyproheptadine and potent 5-HT1A, 5-HT1D, 5-HT2A, and 5-HT2C serotonin receptor antagonists may decrease the efficacy of FINTEPLA.”
Check it at the source: the cyproheptadine FDA label on DailyMed (effective March 6, 2026, Strides Pharma Science Limited); the fenfluramine FDA label on DailyMed (effective October 27, 2025, UCB, Inc.).
What does the cyproheptadine label say about fenfluramine?
Cyproheptadine's label (effective March 6, 2026) does not name fenfluramine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (CYPROHEPTADINE HYDROCHLORIDE), Strides Pharma Science Limited, effective March 6, 2026 (SPL set b28c2ca0-140d-44d8-a59e-75fbfe8eabdd), via openFDA; the full label on DailyMed
What does the fenfluramine label say about cyproheptadine?
Fenfluramine label, drug interactionsCyproheptadine and potent 5-HT1A, 5-HT1D, 5-HT2A, and 5-HT2C serotonin receptor antagonists may decrease the efficacy of FINTEPLA.
Source: FDA drug label (Fintepla), NDA212102 (Ucb Inc), as published by UCB, Inc., effective October 27, 2025 (SPL set e88f360e-33ad-4cd6-b2de-5ef885857c5d), 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
| Cyproheptadine | Fenfluramine | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.0679 per tablet 4 mg tablet | 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