Description
Promtriz (Promethazine) 25 mg
Promtriz 25 mg is a branded oral tablet containing promethazine hydrochloride, a first-generation antihistamine from the phenothiazine class. Official prescribing information for promethazine tablets identifies its use for allergic conditions and for prevention or control of nausea and vomiting, including motion-sickness-related symptoms.
Active Ingredient and Medicine Class
Active ingredient: promethazine hydrochloride.
Medicine class: sedating H1 antihistamine; phenothiazine derivative. Promethazine also has antimuscarinic and antiemetic activity, which contributes to its clinical effects.
Established Medical Uses
Regulatory labeling for promethazine tablets describes use in mild, uncomplicated allergic skin manifestations such as urticaria and angioedema, in allergic reactions to blood or plasma, and as adjunctive therapy in anaphylactic reactions after acute symptoms are controlled. It is also used for prevention and control of nausea and vomiting, including motion sickness and nausea related to surgery or anesthesia.
How It Works
Promethazine blocks histamine H1 receptors, which reduces histamine-driven allergy symptoms. Its sedative, antimuscarinic, and anti-kinetotic actions also help explain its use for nausea, vomiting, and motion sickness. Reviews in PubMed describe promethazine as a competitive H1 antagonist with antihistaminic, sedative, anti-motion-sickness, antiemetic, and antimuscarinic effects.
Important Safety Information
Promethazine is contraindicated in comatose states and in people with hypersensitivity to promethazine or other phenothiazines. Official labeling warns that it should not be used in children under 2 years because of the risk of severe respiratory depression. It should be used cautiously in people with cardiovascular disease or impaired liver function.
Clinically significant interactions can occur with other central nervous system depressants, including alcohol, sedatives, hypnotics, narcotics, anesthetics, tricyclic antidepressants, and tranquilizers, because sedation and impairment may be increased. Labeling also warns about use in breastfeeding because of potential serious adverse reactions in nursing infants.
Possible Side Effects
The most common adverse effect is drowsiness. Other reported effects include dizziness, dry mouth, blurred vision, constipation, confusion, and reduced alertness. Serious reactions can include respiratory depression, paradoxical agitation or hyperexcitability, extrapyramidal symptoms, and neuroleptic malignant syndrome-like reactions.
Scientific Evidence
PubMed-indexed reviews and clinical studies support promethazine’s established role as an antihistamine and antiemetic, especially for motion sickness and nausea/vomiting. Human studies also show that its sedative effects can impair psychomotor performance, which is important when considering safety-sensitive activities.
Medical Information Notice
This summary is for educational use only and is based on sources available at the time of review. It does not replace the official patient leaflet, prescribing information, or individual assessment by a qualified healthcare professional.
Medical Sources
- DailyMed / FDA: Promethazine Hydrochloride Tablets, USP (official prescribing information). View source
- DailyMed / FDA: Promethazine Hydrochloride Tablets, USP (official prescribing information). View source
- Platt DM, et al. Promethazine: A Review of Therapeutic Uses and Toxicity. Journal of Emergency Medicine. 2025. PubMed
