Yes, Promethazine Treats Motion Sickness
Promethazine, an antihistamine, is FDA-approved for preventing and treating motion sickness, including nausea and vomiting from travel by car, boat, or plane. It works by blocking histamine and acetylcholine signals in the brain's vomiting center, reducing dizziness and queasiness.[1][2]
How Does Promethazine Compare to Other Motion Sickness Drugs?
| Drug | Active Ingredient | Form | Duration | Common Side Effects |
|------|-------------------|------|----------|---------------------|
| Promethazine (Phenergan) | Promethazine | Pill, suppository, injection | 4-6 hours | Drowsiness, dry mouth, blurred vision |
| Dramamine | Dimenhydrinate | Pill, chewable | 4-6 hours | Drowsiness, dizziness |
| Scopolamine patch (Transderm Scop) | Scopolamine | Patch | Up to 3 days | Dry mouth, drowsiness, vision changes |
| Meclizine (Bonine) | Meclizine | Pill, chewable | 8-24 hours | Less drowsy than promethazine |
Promethazine is stronger for severe cases but causes more sedation than meclizine.[1][3]
How and When to Take It for Motion Sickness
Take 25 mg orally or as a suppository 30-60 minutes before travel, repeating every 8-12 hours if needed (max 100 mg/day for adults). For kids over 2, use lower doses under doctor guidance. Avoid alcohol or driving due to drowsiness.[2][4]
Who Should Avoid Promethazine?
Not for children under 2 (black box warning for respiratory depression). Use caution if pregnant, elderly, or with glaucoma, asthma, or prostate issues. Stop if seizures or severe confusion occur.[1][2]
When Does It Kick In and How Long Last?
Effects start in 20-30 minutes, peak at 2 hours, and last 4-6 hours. Rectal suppository works faster if vomiting prevents pills.[4]
[1]: FDA Label for Phenergan (Promethazine)
[2]: MedlinePlus: Promethazine
[3]: Drugs.com: Motion Sickness Medications
[4]: Mayo Clinic: Promethazine