Last Updated: 2007-04-06 14:00:17 -0400 (Reuters Health)

WASHINGTON (Reuters) - Companies must stop selling suppositories that contain the ingredient trimethobenzamide to relieve nausea and vomiting because they have not been proven effective, U.S. health officials said on Friday.

The prescription-only suppositories have been sold for children and adults under names including Tigan, Tebamide, T-Gen, Trimazide and Trimethobenz but are not approved, the Food and Drug Administration said.

"Drugs containing trimethobenzamide in suppository form lack evidence of effectiveness," a notice from the Food and Drug Administration said.

About 2 million of the suppositories are prescribed each year, FDA officials said.

There are about five manufacturers and six distributors of the products, said Michael Levy, director of new drugs and labeling compliance in the FDA's drugs compliance office. A list was not immediately available.

FDA officials urged consumers using the suppository form of trimethobenzimde to discuss other options with a doctor.

"There are many alternative products approved to effectively treat nausea and vomiting, and that are available in a variety of forms, including tablets, capsules, solutions, injectables and suppositories," the agency said.

Oral capsules and injectable products made with trimethobenzamide can still be sold, the FDA said.

Companies must stop shipping suppositories with the ingredient by May 9. Any company that wants to keep selling the products must file an application and get FDA approval.

The FDA move is part of an effort to force unapproved medicines from the market.