WASHINGTON (AP) — Federal health officials are lowering the starting dose of the popular sleeping aid drug Lunesta, due to risks of morning drowsiness that can impair driving ability and lead to injury.

The Food and Drug Administration said Thursday it is taking action based on a study that found Lunesta users had problems with driving, memory and coordination up to 11 hours after first taking the drug. Patients are often unaware that they are still drowsy the morning after, according to the FDA.