In the U.S.—

• Antiemetic

Trimethobenzamide ( trye-meth-oh-BEN-za-mide) is used to treat nausea and vomiting.

This medicine is available only with your doctor's prescription in the following dosage forms:

Oral
• Capsules (U.S.)

Parenteral
• Injection (U.S.)

Rectal
• Suppositories (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For trimethobenzamide, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to trimethobenzamide, or if you are allergic or sensitive to benzocaine or other local anesthetics (the suppository form of this medicine contains benzocaine). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies have not been done in pregnant women. However, although studies in animals have not shown that trimethobenzamide causes birth defects, it has been shown to increase the chance of a miscarriage.

Breast-feeding—It is not known whether trimethobenzamide passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are taking this medicine and who wish to breast-feed should discuss this with their doctor.

Children—This medicine should not be used to treat nausea and vomiting in children unless otherwise directed by your doctor. Some side effects may be more serious in children.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of trimethobenzamide in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are using trimethobenzamide, it is especially important that your health care professional know if you are taking any of the following:

• Central nervous system (CNS) depressants (medicine that causes drowsiness) or
• Tricyclic antidepressants (medicine for depression)—Taking these medicines with trimethobenzamide may cause increased CNS depressant or other serious effects

• High fever or
• Intestinal infection—Using trimethobenzamide may result in serious side effects

Do not use this medicine to treat nausea and vomiting in children unless otherwise directed by your doctor. If you are giving this medicine to a child, be especially careful not to give more than is prescribed since side effects may be more serious in children.

Trimethobenzamide is used only to relieve or prevent nausea and vomiting. Use it only as directed. Do not use more of it and do not use it more often than your doctor ordered. To do so may increase the chance of side effects.

To insert the rectal suppository form of this medicine:

• First, remove foil wrapper and moisten the suppository with cold water. Lie down on your side and use your finger to push the suppository well up into the rectum. If the suppository is too soft to insert, chill it in the refrigerator for 30 minutes or run cold water over it before removing the foil wrapper.
• Wash your hands with soap and water.

Dosing—

The dose of trimethobenzamide will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of trimethobenzamide. If your dose is different, do not change it unless your doctor tells you to do so.

The number of capsules that you take, or suppositories that you use, depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking trimethobenzamide.

• For oral dosage form (capsules):
  • For nausea and vomiting:
    • Adults and children 12 years of age and older—250 milligrams (mg) three or four times a day as needed.
    • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 15 mg per kilogram (6.8 mg per pound) of body weight divided into three or four doses. The dose is usually not more than 200 mg three or four times a day as needed.
• For injection dosage form:
  • For nausea and vomiting:
    • Adults and children 12 years of age and older—200 mg three or four times a day as needed, injected into a muscle.
    • Children—Use is not recommended.
• For rectal dosage form (suppositories):
  • For nausea and vomiting:
    • Adults and children 12 years of age and older—200 mg three or four times a day as needed.
    • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 15 mg per kilogram (6.8 mg per pound) of body weight divided into three or four doses. The dose is usually not more than 200 mg three or four times a day as needed.

Missed dose—

If you must use this medicine regularly and you miss a dose, use it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store the capsule form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Trimethobenzamide will add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.

This medicine may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert.

When using trimethobenzamide on a regular basis, make sure your doctor knows if you are taking large amounts of aspirin or other salicylates at the same time (as for arthritis or rheumatism). Effects of too much aspirin, such as ringing in the ears, may be covered up by this medicine.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• Rare
  • Body spasm, with head and heels bent backward and body bowed forward;  convulsions (seizures);  mental depression;  shakiness or tremors;  skin rash;  sore throat or fever;  unusual tiredness;  vomiting (severe or continuing);  yellow eyes or skin 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Drowsiness 
  
  

• Less common
  • Blurred vision;  diarrhea;  dizziness;  headache;  muscle cramps 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.