Definition

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.

  Purpose

The drug described here, prochlorperazine (Compazine), controls both nausea and vomiting. Prochlorperazine is also sometimes prescribed for symptoms of mental disorders, such as schizophrenia.

  Description

Prochlorperazine is available only with a physician's prescription. It is sold in syrup, capsule, tablet, injection, and suppository forms.

Recommended dosage

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.

Doses for children must be determined by a physician.

  Precautions

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. Do not drink alcohol while taking prochlorperazine, and 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 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 this medicine.

Before using prochlorperazine, people with any of these medical problems should make sure their physicians are aware of their conditions:

• Previous sensitivity or allergic reaction to prochlorperazine
• Heart disease
• Glaucoma
• Brain tumor
• Intestinal blockage
• Abnormal blood conditions, such as leukemia
• Exposure to pesticides.

Side effects

Many side effects are possible with this drug, 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.

Interactions

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. Be sure to check with a physician or pharmacist before taking any other prescription or nonprescription (over-the-counter) drug with Prochlorperazine.

   Key Terms:

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, spinal cord and the nerves throughout the body. 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.