Promethazine Overview, Dosage, How to Take, Precautions and Side Effects

What is Promethazine? Promethazine is the generic form of the brand-name drug Phenergan, used as an antihistamine, sedative, and anti-nausea drug. Your doctor may also prescribe promethazine to relieve allergy symptoms like runny nose and watery, red eyes, or prevent and treat motion sickness. Additionally, it can help with allergic skin conditions or reactions to blood or plasma products and may be used to treat the discomforts of a common cold like sneezing, coughing, and runny nose.

What is the dosage for Promethazine?

  • Allergic reactions are treated with 6.25-25 mg orally 3 times daily. A single 25 mg dose administered at bedtime also may suffice. A 25 mg injection is also used.
  • Nausea and vomiting may be managed with 12.5-25 mg administered orally by injection every 4-6 hours as needed.
  • Doses of 25-50 mg by injection are used for sedation before or after surgery.
  • For prevention of motion sickness, 25 mg is used 30 to 60 minutes before the motion begins and then every 8 to 12 hours as needed. Oral, rectal and injectable doses are similar.