The US Food and Drug Administration (FDA) has announced that it will now require stronger warnings about rare but serious incidents related to certain prescription insomnia medicines such as Lunesta (eszopiclone), Sonata (zaleplon) and Ambien (zolpidem).

The change comes after reports of rare but serious injuries and deaths resulting from various complex sleep behaviours after taking these medicines such as sleepwalking, sleep driving and engaging in other activities while not fully awake, such as unsafely using a stove.

The regulator reviewed as many as 66 cases reported to the FDA Adverse Event Reporting System or found in medical literature, in which patients engaged in activities while they were not fully awake that resulted in serious injuries or death. A further 46 reports of non-fatal serious injuries included accidental overdoses, falls, burns, near-drowning, exposure to extreme cold temperatures leading to loss of limb or near death, self-injuries such as gunshot wounds and apparent suicide attempts.

“We recognise that millions of Americans suffer from insomnia and rely on these drugs to help them sleep better at night. While these incidents are rare, they are serious and it’s important that patients and health care professionals are aware of the risk. These incidents can occur after the first dose of these sleep medicines or after a longer period of treatment, and can occur in patients without any history of these behaviours and even at the lowest recommended doses,” said FDA acting commissioner Ned Sharpless.

“Today’s action is an important step in our ongoing effort to call more attention to these critical safety issues and serves as an example of our ongoing commitment to ensuring that patients and health care professionals have the information they need to make informed treatment decisions.”

As a requirement of the new approval, insomnia medicines must be dispensed with a patient medication guide that explains the medicine’s uses and risks.