The first generic versions of the insomnia drug Ambien got U.S. government approval Monday.
The Food and Drug Administration said it approved versions of the immediate-release tablets made by 13 drug companies for the short-term treatment of insomnia. A patent held by Paris-based Sanofi-Aventis on the drug, also called zolpidem tartrate, expired Saturday.
The approvals of generic versions of the drug come a month after the FDA asked makers of it and similar sleep aids to beef up warnings about their potential risks. The risks of the sedative-hypnotic drugs include severe allergic reactions and complex sleep-related behaviors, like sleep-driving.
The FDA said Ambien was the No. 13 brand-name drug by sales last year.