WASHINGTON — All prescription sleeping pills may sometimes cause sleep-driving, federal health officials warned yesterday, almost a year after the bizarre side effect first made headlines when Rep. Patrick Kennedy crashed his car after taking Ambien.

It’s a more complicated version of sleepwalking, but behind the wheel: getting up in the middle of the night and going for a drive — with no memory of doing so.

The Food and Drug Administration wouldn’t say exactly how many cases of sleep-driving it had linked to insomnia drugs, but neurology chief Dr. Russell Katz said the agency uncovered more than a dozen reports — and is worried that more are going uncounted.

Given the millions of prescriptions for insomnia drugs, Dr. Katz called the problem rare and said he was unaware of any deaths. But because sleep-driving is so dangerous — and there are precautions that patients can take — the FDA ordered a series of strict new steps yesterday.

First, the makers of 13 sleep drugs must put warnings on their labels about two rare but serious side effects:

• Sleep-driving, along with other less dangerous “complex sleep-related behaviors” — like making phone calls, fixing and eating food, and having sex while still asleep.

• Life-threatening allergic reactions, as well as severe facial swelling, both of which can occur either the first time the pills are taken or anytime thereafter.

Some of the insomnia drugs may be riskier than others, so FDA also recommended that manufacturers conduct clinical trials to figure that out. The drugs are: Ambien; Butisol sodium; Carbrital; Dalmane; Doral; Halcion; Lunesta; Placidyl; Prosom; Restoril; Rozerem; Seconal; Sonata.