The FDA has asked manufacturers to stop making suppository drug products that contain trimethobenzamide hydrochloride. The suppositories are most commonly known as Tigan but are also marketed under other names including Tebamide, T-Gen, Trimazide and Trimethobenz. The drug is used for nausea and vomiting in adults and children due to motion sickness and stomach viruses.
The drug is FDA approved in oral and IV forms but not in suppository form. The action is part of a larger FDA effort to deal with prescription drugs that are not FDA approved, many of which were on the market before the FDA started regulating the effectiveness of drugs in 1962.
The story of this drug is interesting. In 1971, the FDA ruled that the drug was effective for motion sickness and other similar causes of nausea and vomiting, but not stomach viruses (though it is very often used for this). In 1979, the FDA ruled that the drug was not effective in suppository form (though it is still commonly used this way). Twenty-eight years later, the FDA is now regulating the drug based on its lack of effectiveness in this form. The delay is due to the fact that one drug company (and its successor) has been considering this whole time doing a study on the effectiveness of the suppositories and applying for FDA approval. In 2005, the company notified the FDA that it was not going to pursue approval. The FDA is therefore withdrawing any approval of the drug in suppository form due to complete lack of evidence that it is effective.
Another interesting aspect of this story is that I see this drug used all the time by other doctors. However, it has never been shown to be effective. This highlights the importance of practicing evidence-based medicine, using drugs and treatments that have been shown to be safe and effective. It also brings up the issue of all the drugs on the market that are not FDA approved. Many people are unaware of this fact, though it has been in the press a good deal over the past year.
