What the FDA labels say about taking them together
Promethazine and zaleplon
Zaleplon's FDA label of May 8, 2024 names promethazine in its drug interactions section; the promethazine label PlainMeds reads does not name zaleplon. The zaleplon label: “Promethazine Coadministration of a single dose of zaleplon and promethazine resulted in a 15% decrease in maximal plasma concentrations of zaleplon, but no change in the area under the plasma concentration-time curve.”
Check it at the source: the promethazine FDA label on DailyMed (effective March 13, 2026, KVK-Tech, Inc.); the zaleplon FDA label on DailyMed (effective May 8, 2024, Aurobindo Pharma Limited).
What does the promethazine label say about zaleplon?
Promethazine's label (effective March 13, 2026) does not name zaleplon in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (PROMETHAZINE HYDROCHLORIDE), KVK-Tech, Inc., effective March 13, 2026 (SPL set 7a137adf-39b7-4b14-80da-c3cac9ad562a), via openFDA; the full label on DailyMed
What does the zaleplon label say about promethazine?
Zaleplon label, drug interactionsPromethazine Coadministration of a single dose of zaleplon and promethazine (10 and 25 mg, respectively) resulted in a 15% decrease in maximal plasma concentrations of zaleplon, but no change in the area under the plasma concentration-time curve.
Source: FDA drug label (ZALEPLON), Aurobindo Pharma Limited, effective May 8, 2024 (SPL set e092f3ca-bf44-4568-a72c-3fb2cf5b192b), 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
| Promethazine | Zaleplon | |
|---|---|---|
| Labeled for | n/a | Insomnia |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.0455 per tablet 25 mg tablet | $0.141 per capsule 10 mg capsule |
| Shortage now | In shortage | 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