promethazine

Adjunctive therapy • Brands: PHENERGAN

Last reviewed: 2025-12-30

General information

Class: Adjunctive therapy
Common US brands: PHENERGAN
Therapeutic drug monitoring not routinely recommended.
Last reviewed: 2025-12-30

Dosing & forms

Forms/strengths: —
Frequency: —
Food: —
Typical range: —

Mechanism (brief)

Sedating first-generation antihistamine (H1 antagonist) and phenothiazine derivative with anticholinergic/antiemetic properties; used for allergy symptoms, nausea, motion sickness, and sedation.

Metabolism & Half‑life

Metabolism: Hepatic
Half‑life: —

Therapeutic Drug Monitoring (TDM)

Recommended: No

View labelExact

Monitoring highlights

Sources

Promethazine hydrochloride tablets prescribing information — DailyMed (2025)
Promethazine (StatPearls) — StatPearls Publishing (NCBI Bookshelf) (2025)
2023 American Geriatrics Society Updated Beers Criteria for Potentially Inappropriate Medication Use in Older Adults — Journal of the American Geriatrics Society (2023)
Pharmacokinetics of promethazine and its sulphoxide metabolite after intravenous and oral administration to man — British Journal of Clinical Pharmacology (1983)