The group, chaired by Dr. Clifford Rosen, acknowledged in a 20-3 vote that the drug might increase heart attack risk in some patients. However, it then voted 22-1 to keep Avandia on the market anyway.

The majority of panel members called for stronger warnings, including a "black box" warning on the drug's label. The black box represents the FDA's strongest cautionary advice.

Some members noted that a warning against combining Avandia with insulin should be provided, since that appears to increase the risk of heart problems. Use of the two drugs together is presently FDA-approved.

43 Percent Higher Heart Attack Risk

There are approximately 21 million Americans diagnosed with type 2 diabetes -- a disease characterized by inadequate control of blood sugar. Diabetics are more vulnerable to heart disease, kidney failure and limb amputation among other complications.

Avandia, GlaxoSmithKline's second biggest seller, is prescribed to millions of diabetics. An analysis released by the Cleveland Clinic earlier this year tied the drug to a 43 percent higher heart attack risk -- the first time such a link was made public.

However, the manufacturer claims there is evidence that contradicts the Cleveland Clinic's research results and recommended further study.

A delay in taking action pending further research could put upwards of 2,200 people per month at risk of suffering dangerous side effects, argued FDA scientist Dr. David Graham, speaking to the panel.

Benefits Questioned

He also noted that the drug does not offer unique short-term benefits in controlling blood sugar levels in diabetics.

Certain diabetics -- namely those with heart failure or cardiovascular disease, or those taking nitrates or insulin -- are more at risk than others, observed Rosen.

Avandia sales have been impacted by the controversy surrounding its safety, but GlaxoSmithKline shares rose on Monday following news of the advisory panel's recommendation.

The FDA is not required to follow the advice of its advisory committees, but it usually does.