It sounds like an insomniac’s dream: a sleeping pill that can be taken for weeks or even months at a time, without the risk of addiction or morning-after grogginess.

In the next several weeks consumers will see splashy print and television ads touting the lyrically named Lunesta, which was approved last month by the U.S. Food and Drug Administration. Unlike other sleeping pills, including market leader Ambien, which are not supposed to be taken for longer than 10 days at a time, Lunesta has no FDA recommended time limit.

Some sleep specialists question the wisdom of using a sleeping pill for weeks or months on end, particularly when it is a new drug approved after six months of testing in 2,700 patients.

They cite the fresh examples of the increased risk of heart attack and stroke from arthritis pain relievers Vioxx, Celebrex and Bextra, the dangers of which emerged after millions of patients started taking them.

“The best thing to do is to avoid getting into a situation where you need a medication long-term,” said Northern Virginia neurologist John Cochran. For a small group of patients who have been adequately screened to rule out underlying physical or psychiatric problems — such as depression or anxiety — that might cause insomnia, long-term use of a sleeping medication may be indicated, he said.

To treat insomnia many sleep specialists, including Cochran, recommend behavioral strategies that fall under the schoolmarmish rubric “sleep hygiene.” They include relaxation techniques as well as avoidance of caffeine, alcohol and large meals before bedtime. Sleeping pills are often used short-term, to break the cycle of sleeplessness and the anxiety it causes.

Cochran said he worries that many consumers, eager for a speedy and easy remedy, will get a prescription for Lunesta from a primary care doctor who has neither the time nor the training to suggest behavioral techniques or conduct a comprehensive evaluation.

“That means some doctors will give it to patients who will stay on it forever,” he said.

Symptoms of insomnia — difficulty falling or staying asleep — are extremely common. A 2002 poll by the National Sleep Foundation found that 58 percent of adults experience them a few times each week and one-third have nightly symptoms.

In about 15 percent of cases, sleep specialists say, chronic insomnia has no apparent underlying cause.