 - Any malaria treatment or use of azithromycin or other macrolides, tetracyclines, sulfonamides, doxycycline, tetracycline or other sulfa based or other drug with antimalarial activity for the previous 4 weeks prior to screening. Additionally, concomitant use of phenobarbitol, rifampin, phenytoin, fosphenytoin, cimetidine, ketoconazole, cholestryramine constitute exclusion criteria. 