GlaxoSmithKline ( GSK) said Tuesday that it received federal approval to sell the drug Avandamet as an initial therapy for diabetes. Avandamet was approved in 2002 as a second-line therapy for patients who can't control their blood-sugar levels with another drug. The company said it now has an adequate supply of the drug, more than 15 months after federal officials seized batches of Avandamet and the antidepressant Paxil CR and ordered a halt to their sales. The drugs were confiscated because the Food and Drug Administration said the company had failed to adequately and promptly address manufacturing problems at a plant in Puerto Rico. In April 2005, GlaxoSmithKline entered an agreement with federal regulators , a month after the products were seized, to improve its manufacturing and quality-control practices. By the middle of last year, the company was shipping Paxil CR again. Although Avandamet returned to the market 12 months ago , the supply fell well short of demand as quality-control measures were implemented. A spokeswoman said GlaxoSmithKline decided against actively promoting the drug until there was a sufficient supply. Avandamet combines another GlaxoSmithKline drug, Avandia, with metformin, a now-generic medication. Avandia helps muscle cells be more responsive to insulin, the protein hormone that helps the body convert sugar into fuel. Metformin prompts the liver to produce less sugar. Many diabetics take more than one drug to control their blood-sugar levels, and combination pills offer a measure of convenience. Avandamet is prescribed for people with Type 2 diabetes, the most common form of the disease, in which the body doesn't produce enough natural insulin or doesn't respond properly to insulin.