Sleep medications like Ambien have long been controversial and have been linked to bizarre behavior in users.

On Tuesday, the Food and Drug Administration (FDA) announced that it is requiring manufacturers of Ambien and other sleep medications to add a Boxed Warning – the agency's most prominent warning – to the prescribing information and the patient Medication Guides for these drugs.

Often referred to as a "black box warning", the label is the strictest alert placed on prescription drugs or drug products by the FDA when there is reasonable evidence of an association of a serious hazard with the drug. As the name indicates, it is a warning with a black box around it. Having the black box around the warning means that an adverse reaction to the drug may lead to death or serious injury.

Prescription sleep medications carry terrifying risks.

The agency is warning the public that rare but serious injuries and deaths have been linked to the use of certain common prescription insomnia drugs. Dangerous behaviors appear to be more common with eszopiclone (Lunesta), zaleplon (Sonata), and zolpidem (Ambien, Ambien CR, Edluar, Intermezzo, Zolpimist) than other prescription medicines used for sleep, according to the FDA's Safety Announcement.

Sleepwalking, sleep driving, and engaging in other activities while not fully awake (like using the stove) are among the risks associated with the medications, the agency explains:

We identified 66 cases of complex sleep behaviors occurring with these medicines over the past 26 years that resulted in serious injuries, including death. This number includes only reports submitted to FDA or those found in the medical literature, so there may be additional cases about which we are unaware.

These cases included accidental overdoses, falls, burns, near drowning, exposure to extreme cold temperatures leading to loss of limb, carbon monoxide poisoning, drowning, hypothermia, motor vehicle collisions with the patient driving, and self-injuries such as gunshot wounds and apparent suicide attempts. Patients usually did not remember these events. The underlying mechanisms by which these insomnia medicines cause complex sleep behaviors are not completely understood. (source)