The FDA asked five drugmakers to end the manufacturing and marketing of suppository drug products containing trimethobenzamide hydrochloride, due to lack of evidence of effectiveness. The products, used to treat nausea and vomiting in adults and children, have been marketed under various names including Tigan, Tebamide, T-Gen, Trimazide and Trimethobenz. The FDA is asking five manufacturers and six distributors of the unapproved suppositories to stop making and distributing them. The agency did not immediately identify the drug companies and distributors. Companies making or marketing trimethobenzamide hydrochloride suppository products must cease shipping them in interstate commerce by May 9, the FDA said. A small amount of these products will still be available in pharmacies until supplies are exhausted. After May 9, any company wishing to market a product containing trimethobenzamide in suppository form must obtain an approved New Drug Application prior to marketing, the agency said. If the companies and distributors do not comply, the government can seize the products and force the companies to stop making the drugs through a court order. The action is part of an ongoing FDA effort to pursue prescription drugs that do not have agency approval. Many of those unapproved drugs were on the market prior to a 1962 law requiring the agency to evaluate a drug’s safety and effectiveness before allowing it on the market. Earlier laws focused mainly on drug safety.