Nov 14, 1997-A Food and Drug Administration committee met Thursday and gave an initial thumbs up to Propecia, Merck's anti-baldness drug, while raising questions about its long-term side effects.

The committee was considering the one-a-day pill known as Propecia, to determine whether it is both safe and effective. Advisers told the FDA that Propecia appears to help some men grow new hair.

But the FDA panel stopped short of give a total endorsement of Merck & Co.'s new pill raising questions over whether men who took the pill for years would suffer fertility problems and other unforeseen side effects.

The panel, without a vote, concluded that the pill was effective and left the safety question to the government. Now it is up to the FDA to decide whether to require Merck to extend the study of the drug or allow its sale and keep tabs on what happens to balding men over time. If approved, it could be available by the end of the year.

Merck's Propecia is a once-a-day pill that promises to help regrow hair -- and prevent more from falling out -- by suppressing a hormone that shrinks hair follicles.

Propecia actually is a lower dose of a popular drug that men already use for enlarged prostates, called Proscar. For the merely hair-impaired, Merck says a safe dose is 1 milligram a day of the active ingredient, finasteride, not the 5-milligram Proscar pills that prostate patients take. The company also claims that serious side-effects already would have emerged in the millions of older men who take the 5-milligram pill to shrink enlarged prostates.

And although women suffer hair loss, too, Merck says Propecia can never be used by them -- the threat of birth defects is too great. Doctors even tell women not to touch the pills for fear the drug could be absorbed through their skin.

Merck showed the FDA's scientific advisers studies of 1,553 men that found 86 percent of those who took Propecia grew more hair or maintained the amount they had, compared with just 42 percent of men who took a placebo.

Investigators spent two years counting the hairs in specific sections of men's scalps, and those who didn't get Propecia treatment lost 2.5 percent of their hair every year, while hair counts were stable for the treated men.

But the big question for the FDA, is whether using a pill that affects hormones is safe for a simply cosmetic problem.

Merck says side effects included decreased libido and impotence in 2 percent of the men who took Propecia, a number that seems insignificant, since 1.3 percent of men who took the placebo experienced reported the same problems.

Propecia works by blocking production of a testosterone-related hormone called dihydrotestosterone, or DHT, that causes hair loss.

While Propecia can cut men's DHT levels by 60 percent, greater results have been seen in men who used both Propecia and Rogaine