Promethazine hydrochloride
Trade Names:
Anergan, Phenameth, Phenergan
Type of Drug:
Promethazine hydrochloride belongs to a general class of antinausea drugs called antihistamines.
How Drug Works:
Promethazine hydrochloride has sedative, antihistamine, and mild antinausea properties. It has a depressant effect on the central nervous system (CNS), but the specific mechanism is not known.
How Drug Is Given:
Promethazine hydrochloride is given as a pill or liquid by mouth, as a rectal suppository, or as an injection in a vein over 5 minutes or in a muscle. Shake the liquid well before pouring the dose. If you are taking the suppository, open the package and dip the tip of the suppository in water. If you are right-handed, lie down on your left side, bring your knees up near your chest, and insert the suppository in your rectum about an inch. Stay in this position for about 15 minutes, then get up and wash your hands well. The dose depends on the reason you are taking it. Keep the medicine in a tightly closed container away from heat and moisture and out of the reach of children and pets.
How Should I Take This Drug?
Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you.
Read the following information. If you do not understand it or if any of it causes you special concern, check with your doctor.
Before taking this drug, tell your doctor if you are taking any other prescription or over-the-counter drugs, including vitamins and herbals.
Should I avoid any other medicines, foods, alcohol, and/or activities?
Your prescription and nonprescription medicines may interact with other drugs, causing harm. Certain foods or alcohol can also interact with drug products. Never begin taking a new medicine"prescription or nonprescription"without asking your doctor or nurse if it will interact with alcohol, food, or other medicines. Some drug products can cause drowsiness and affect activities such as driving.
Precautions:
Promethazine hydrochloride may make you feel very sleepy. Do not drive or operate heavy machinery when you are drowsy.
Promethazine hydrochloride may cause increased risk of confusion, sedation, and drowsiness in the elderly. This drug should be used cautiously in the elderly. It is important to protect against falls or injury.
Tell all the doctors, dentists, and pharmacists you visit that you are taking this drug.
  • Most of the following side effects probably will not occur.
  • Your doctor or nurse will want to discuss specific care instructions with you.
  • They can help you understand these side effects and help you deal with them.
Side Effects:
More Common Side Effects
  • Drowsiness
  • Dry mouth
  • Constipation
Less Common Side Effects
  • Confusion
  • Sedation
  • Restlessness
  • Tremors
  • Blurred vision
  • Decreased blood pressure
Rare Side Effects
  • Nausea
  • Vomiting
  • Difficulty urinating
Side Effects / Symptoms of the Drug

Be careful when getting up, changing position, or walking.
Other side effects not listed above can also occur in some patients. Tell your doctor or nurse if you develop any problems.
FDA Approval: Yes