The Food and Drug Administration on Wednesday approved a new dosage formulation of Agouron Pharmaceuticals' protease inhibitor Viracept. The drug previously was available in a 50-milligram oral powder and 250-milligram tablets. The new formulation of 625-milligram tablets will reduce the medication's pill burden from five 250-milligram tablets taken twice a day to two 625-milligram tablets taken twice a day. Clinical trials showed that the new dosage formulation is actually more effective at keeping high levels of the drug in the bloodstream over longer periods of time than the previous regimen. Agouron officials say that diarrhea, a side effect of the medication, may be more severe for some patients taking the higher-dosage tablets. Viracept was first approved for the treatment of HIV infection in 1997.