Phenergan (promethazine) — what you need to know

Phenergan is the brand name for promethazine, a medication used for nausea, motion sickness, allergies, and as a mild sedative. It calms the inner ear and blocks histamine, so it helps with vomiting and allergic reactions. People also use it before surgery to reduce nausea or to help sleep for short periods.

How Phenergan is used and dosed

For adults, common oral doses are 12.5–25 mg every 4–6 hours as needed, with a typical daily maximum around 100 mg. For motion sickness, a single 25 mg dose an hour before travel often works. Suppositories and injections exist, but injection has special risks — never accept an IV shot without a clear medical reason and monitoring. Pediatric dosing is narrower and children under 2 years must not receive promethazine because of serious breathing risks.

Timing matters. Take the pill with water; if you feel very drowsy afterward, avoid driving or using machinery. If your doctor prescribes it for chronic problems, follow their exact schedule rather than repeating short-term dosing advice you read online.

Side effects, warnings and interactions

Common side effects include drowsiness, dry mouth, blurred vision, and constipation. Serious risks are respiratory depression (especially in young children), low blood pressure, and severe tissue injury or gangrene with improper injection. Older adults face higher fall risk and stronger sedation.

Phenergan boosts the sedative effect of alcohol, opioids, benzodiazepines, and other CNS depressants — don’t mix them without a doctor’s okay. It may interact poorly with MAO inhibitors, and people with glaucoma, enlarged prostate, or severe lung problems should be cautious. If pregnant or breastfeeding, discuss risks with your provider; promethazine can affect newborns if used near delivery.

Watch for signs of allergic reaction, breathing trouble, high fever, stiff muscles, or sudden confusion. Those need urgent medical attention.

If a dose is missed, take it when you remember unless it’s almost time for the next dose. Don’t double up to catch up.

Thinking about buying Phenergan online? Make safety the priority. Legitimate pharmacies require a prescription, list a licensed pharmacist, show a physical address, and use secure website encryption (look for https and a padlock). Beware of sites selling large amounts without a prescription or offering suspiciously low prices.

Before ordering, call the pharmacy and ask about dispensing rules, country of origin, and return policy. Keep your prescriber in the loop so they can monitor side effects and interactions. When in doubt, talk to a pharmacist or your doctor — they can help you choose the safest option for your situation.