Promethazine and Zaleplon Interaction
Drug interaction information between Promethazine and Zaleplon.
Promethazine and Zaleplon have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Promethazine and Zaleplon. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Promethazine slightly reduces the highest level of zaleplon in your blood, but the total amount in your body remains about the same.
FDA Label Information
Promethazine: 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. However, the pharmacodynamics of coadministration of zaleplon and promethazine have not been evaluated.
Promethazine Also Interacts With
- Epinephrine minor
- Famciclovir minor
Zaleplon Also Interacts With
- Ibuprofen minor
- Venlafaxine minor
- Paroxetine minor
- Warfarin minor
- Ketoconazole minor
Frequently Asked Questions
What SPL severity band is on file for Promethazine + Zaleplon?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Zaleplon has 16 labeled pairs on file vs Promethazine's 3. In the minor band specifically: Promethazine has 3 (also Epinephrine, Famciclovir); Zaleplon has 16 (also Ibuprofen, Venlafaxine, Paroxetine, Warfarin).
What mechanism field is on file for Promethazine and Zaleplon?
Promethazine slightly reduces the highest level of zaleplon in your blood, but the total amount in your body remains about the same.
Zaleplon's labeled portfolio outnumbers Promethazine
SPL source-record counts only. This page's band is minor · classes on file: Promethazine (Phenothiazine Antiemetic / Antihistamine); Zaleplon (Non-Benzodiazepine Hypnotic (Z-Drug)).
0 major · 0 moderate · 3 minor · 3 total
- Other minor peers for Promethazine
- Epinephrine
- Famciclovir
0 major · 0 moderate · 16 minor · 16 total
- Other minor peers for Zaleplon
- Ibuprofen
- Venlafaxine
- Paroxetine
- Warfarin
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.