The US Food and Drug Association on Wednesday called for stronger warning labels on Lunesta and Ambien, as well as 11 other sleep medications.

In addition to driving while asleep, other drug-induced behaviors may include making phone calls, engaging in sex, cooking and eating while in a sleep state. People who experience these side-effects have no memory of what they have done when they awaken.

The sleep aids also may cause severe allergice reactions in some cases, including anaphylaxis and severe facial swelling.

Despite the concerns, the FDA has not suggested withdrawing any of the sedative-hypnotic drugs from the market, maintaining that thay can be used safely.

Those risks include doing various activities such as driving while asleep -- so-called "sleep driving" -- without any recollection afterward, the FDA said. Patients taking the drugs were also found to make phone calls, have sex, eat and cook while asleep.

The sometimes-bizarre behavior associated with these medications is very rare, officials said, and no deaths have been reported. However, many other serious incidents may be attributable to sleeping pill side-effects.

One high-profile case involved Rep. Patrick Kennedy, D-RI, who was arrested for driving under the influence of prescription drugs after the car he was driving crashed near the Capitol last year. The congressman later said he had taken Ambien and another sedative, Phenergan, and had no recollection of the incident. After pleading guilty to the offense, Kennedy was ordered to enter drug treatment and placed on probation for one year.