Antiemetics (Phenothiazines)

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Antiemetics (Phenothiazines)


Generic NameBrand Name
prochlorperazineCompro, Procomp

These medicines are available as injections, tablets, suppositories, or syrup.

How It Works

Promethazine and prochlorperazine act on the brain to stop nausea and vomiting.

Why It Is Used

These medicines are used to prevent and control severe nausea and vomiting.

How Well It Works

Promethazine and prochlorperazine can help stop nausea and vomiting.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.

Call your doctor right away if you have:

  • Signs of a serious neurologic problem (neuroleptic malignant syndrome), including:
    • Stiff muscles.
    • Fever.
    • Trouble breathing or fast breathing.
    • Seizures.
    • Fast heartbeat.
    • Increased sweating.
    • Unusually pale skin.
    • Unusual tiredness or weakness.
    • Loss of bladder control.
  • Signs of respiratory depression, including:
    • Pale or blue lips, fingernails, or skin.
    • Trouble breathing, including fast, slow, or shallow breathing and shortness of breath.

Call your doctor if you have:

  • Hives.
  • Uncontrollable face or body movements.
  • Vision problems, including blurry vision.
  • Problems with balance.
  • Fainting.
  • Restlessness.
  • Shuffling walk.
  • Trembling or shaking of hands and fingers.

Common side effects of this medicine include:

  • Constipation.
  • Decreased sweating.
  • Dizziness.
  • Drowsiness.
  • Dry mouth.
  • Stuffy nose.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

These medicines should not be used by children who weigh less than 20 lb (9.07 kg) or are younger than age 2. Young children seem to be more likely to develop side effects.

Dry mouth is common with these medicines. To help with dry mouth, you can chew sugarless gum, suck on sugarless candy, or melt ice in your mouth. If you continue to have problems with dry mouth after a couple of weeks, call your doctor. Dry mouth can lead to tooth decay and gum disease.

These medicines can make your skin more sensitive to the sun.

  • Stay out of the sun, if possible.
  • Wear long pants, long-sleeved shirts, and hats, if possible.
  • Use sunscreen with an SPF that your doctor recommends.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.


ByHealthwise Staff
Primary Medical ReviewerAnne C. Poinier, MD - Internal Medicine
Specialist Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Last RevisedDecember 19, 2012

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