Antinausea drugs are medicines that control nausea—a feeling of sickness or queasiness in the stomach with an urge to vomit. These drugs also prevent or stop vomiting. Drugs that control vomiting are called antiemetic drugs.
Antinausea drugs such as prochlorperazine (Compazine), usually control both nausea and vomiting. Prochlorperazine is also sometimes prescribed for symptoms of mental disorders, such as schizophrenia.
Another commonly prescribed antinausea drug is promethazine (Phenergan). Promethazine also may be prescribed to relieve allergy symptoms and apprehension, as well as motion sickness.
Prochlorperazine is available only with a physician's prescription. It is sold in syrup, capsule, tablet, injection, and suppository forms.
To control nausea and vomiting in adults, the usual dose is:
- Tablets—one 5-mg or 10-mg tablet three to four times a day
- Extended-release capsules—one 15-mg capsule first thing in the morning or one 10-mg capsule every 12 hours
- Suppository—25 mg, twice a day
- Syrup—5-10 mg three to four times a day
- Injection—5-10 mg injected into a muscle three to four times a day.
|Brand Name (Generic
|Possible Common Side Effects Include:|
|Involuntary muscle spasms, dizziness,
jitteriness, puckering of the mouth
|Dizziness, dry mouth, nausea and vomiting,
|Fatigue, drowsiness, restlessness|
|Blurred vision, diarrhea, cramps, headache|
|Constipation, headache, fatigue, abdominal
Doses for children must be determined by a physician.
Promethazine may be administered in pill, syrup, chewable tablet, or extended release capsule form by prescription only. For severe nausea, it may be administered by injection or via a suppository. The physician recommends dose depending on the patient's condition.
Anesthetic — Medicine that causes a loss of feeling, especially pain. Some anesthetics also cause a loss of consciousness.
Antihistamine — Medicine that prevents or relieves allergy symptoms.
Central nervous system — The brain and spinal cord.
Spasm — Sudden, involuntary tensing of a muscle or a group of muscles.
Tranquilizer — Medicine that has a calming effect and is used to treat anxiety and mental tension.
Prochlorperazine may cause a movement disorder called tardive dyskinesia. Signs of this disorder are involuntary twitches and muscle spasms in the face and body and jutting or rolling movements of the tongue. The condition may be permanent. Older people, especially women, are particularly at risk of developing this problem when they take prochlorperazine.
Some people feel drowsy, dizzy, lightheaded, or less alert when using this medicine. The drug may also cause blurred vision, and movement problems. For these reasons, anyone who takes this drug should not drive, use machines or do anything else that might be dangerous until they have found out how the drug affects them.
Prochlorperazine makes some people sweat less, which can allow the body to overheat. The drug may also make the skin and eyes more sensitive to the sun. People who are taking prochlorperazine should try to avoid extreme heat and exposure to the sun. When going outdoors, they should wear protective clothing, a hat, a sunscreen with a skin protection factor (SPF) of at least 15, and sunglasses that block ultraviolet (UV) light. Saunas, sunlamps, tanning booths, tanning beds, hot baths, and hot tubs should be avoided while taking this medicine. Anyone who must be exposed to extreme heat while taking the drug should check with his or her physician.
This medicine adds to the effects of alcohol and other drugs that slow down the central nervous system, such as antihistamines, cold and flu medicines, tranquilizers, sleep aids, anesthetics, some pain medicines, and muscle relaxants. Drinking alcohol while taking prochlorperazine is not advised and patients should check with the physician who prescribed the drug before combining it with any other medicines.
Do not stop taking this medicine without checking with the physician who prescribed it. Stopping the drug suddenly can cause dizziness, nausea, vomiting, tremors, and other side effects. When stopping the medicine, it may be necessary to taper down the dose gradually.
Prochlorperazine may cause false pregnancy tests.
Women who are pregnant (or planning to become pregnant) or breast feeding should check with their physicians before using antinausea medicines.
Before using prochlorperazine, people with any of the medical problems should make sure their physicians are aware of their conditions:
- Previous sensitivity or allergic reaction to prochlorperazine
- Heart disease
- Brain tumor
- Intestinal blockage
- Abnormal blood conditions, such as leukemia
- Exposure to pesticides.
Some people may experience side effects from promethazine including:
A physician should be contacted immediately if a patient experiences the following effects while taking promethazine:
- vision problems
- ringing in the ears
- yellowing of the skin or eyes
- skin rash.
Many side effects are possible with prochlorperazine, including, but not limited to, constipation, dizziness, drowsiness, decreased sweating, dry mouth, stuffy nose, movement problems, changes in menstrual period, increased sensitivity to sun, and swelling or pain in breasts. Anyone who has unusual or troublesome symptoms after taking prochlorperazine should get in touch with his or her physician.
Side effects associated with promethazine include those listed above and interactions with various medications that may cause complications or lessen the effects of the drug. A physician should be notified of other medications the patient is on when taking promethazine.
Prochlorperazine may interact with other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Among the drugs that may interact with prochlorperazine are antiseizure drugs such as phenytoin (Dilantin) and carbamazepine (Tegretol), anticoagulants such as warfarin (Coumadin), and drugs that slow the central nervous system such as alprazolam (Xanax), diazepam (Valium), and secobarbital (Seconal). Not every drug that interacts with prochlorperazine is listed here. A physician or pharmacist can advise patients about prescription or nonprescription (over-the-counter) drugs that might interact with Prochlorperazine.
Flake, Zachary A., Robert D. Scalley, and Austin G. Bailey. "Practical Selection of Antiemetics." American Family Physician March 1, 2004: 1169.
"Promethazine" Medline Plus Drug Information. http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a682284.html#precautions.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.