As the Harvard University researchers have commenced another trial of diabetes drug Avandia, in order to prove its worth, the Food and Drug Administration in US has put a restriction on the number of people registering to take part in it.

The advisory panel said that no new admissions shall be observed for the trial further.

Meanwhile, those patients, who have already registered themselves for TIDE (Thiazolidinedione Intervention with Vitamin D Evaluation) trial, will not be denied participation.

Over the last one week, the panelists from FDA have been pondering over the effectiveness of the drug and the side effects associated with its use.

The panel agreed that Avandia elevates the risk of heart attacks in users, but it allowed the availability of the drug in the market, in view of the absence of any justifications on the risk of heart attack.

Following the release of the first report claiming the side effects of the drug in 2007, its sales have been tumbling, bringing huge losses to producer GlaxoSmithKline.

"This pause in enrollment will give clinical trial investigators and patients time to learn about the data presented to the FDA", said Dr. Ellen Strahlman, GSK's Chief Medical Officer.