US regulators have requested that all manufacturers of sedative-hypnotic sleeping pills, including sanofi-aventis’ Ambien/Ambien CR (zolpidem) and Sepracor’s Lunesta (eszopiclone), strengthen the warnings on the product labelling about the potential risks associated with this class of drugs.

According to the Food and Drug Administration, these risks include severe allergic reactions and complex sleep-related behaviours, such as sleep-driving, which is defined as driving while not fully awake after taking a sedative-hypnotic product and having no memory of the event.

"There are a number of prescription sleep aids available that are well-tolerated and effective for many people," said Steven Galson, Director of FDA’s Center for Drug Evaluation and Research. "However, after reviewing the available post-marketing adverse event information for these products, FDA concluded that labelling changes are necessary to inform health care providers and consumers about risks."

Along with the labelling revisions, FDA has requested that each product manufacturer send letters to health care providers to notify them about the new warnings, and that Patient Medication Guides are developed to help inform patients about the risks.

Although all sedative-hypnotic products have these risks, there may be differences among products in how often they occur, the agency notes. Therefore, it has recommended that the drugmakers carry out clinical studies to assess the frequency with which sleep-driving and other behaviours occur with individual drug products.