(CBS NEWSPATH) The FDA is issuing an urgent safety alert for people taking prescription sleeping pills. 

The warning includes Lunesta, Sonata and Ambien

There have been 20 reports of deaths and several rare but serious injuries from dangerous side effects. 

There are documented cases of sleepwalking, sleep driving and performing other activities like using a stove while not fully awake. 

This is not a recall. The FDA is clarifying the potential danger of these sleep drugs. 

The agency will require new warnings on the boxes and will continue to monitor side effects and incidents. 

Black box warnings are the FDA’s most prominent warning. The FDA said the three drugs affected by the warning — zolpidem, eszopiclone and zaleplon — should not be given to anyone who has experienced “complex sleep behavior” such as sleepwalking.

“They wake up for some reason during sleep and they exhibit behaviors we would perform while awake, like walking, eating, potentially even driving,” Dr. Nancy Foldvary-Schaefer of the Sleep Disorders Center at Cleveland Clinic told CBS News.

It’s not clear why some people experience more troubling side effects than others.

“It may be that some people are genetically prone anyway to these kinds of disorders and the medication can become an additional trigger,” Foldvary-Schaefer said. 

Doctors say while side effects from sleeping pills are rare, they can lead to serious or even life-threatening harm.

The FDA issued the new requirement after a safety review involving 66 cases in which patients engaged in activities resulting in serious injuries or death, such as sleepwalking or driving while not fully awake. The FDA says some suffered falls, burns, near-drowning, car crashes, or lost limbs after exposure to extreme cold temperatures. Of those cases, 20 people died.

“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 behaviors and even at the lowest recommended doses,” FDA Acting Commissioner Ned Sharpless, M.D., said in a statement.

Foldvary-Schaefer says the government’s warning is an important reminder that medication should not be the only tool for addressing insomnia.