From ABC ...

In a presidential race marked by references to preparedness in the face of the 3 a.m. call, the revelation that presumptive Republican nominee Sen. John McCain has taken the sleeping pill Ambien during his travels raises concerns that the rare side effects of the medication could impair his judgment.

"Taking more than the recommended dosage of Ambien or combining it with other sedative-hypnotics -- for example, alcohol -- may result in amnesia, fugue states and sleep walking," said Dr. Peter A. Fotinakes, medical director of the St. Joseph Sleep Disorders Center in Orange, Calif. "Used appropriately, Ambien is a relatively safe medication."

Though rare, such side effects associated with Ambien have made headlines.