Percent erythromycin metabolism per hour, as measured by the ERMBT at baseline, at the end of each dosing regimen, and at follow-up. The line connects the means. APV, 1,200 mg of amprenavir given orally twice a day; CLAR, 500 mg of clarithromycin given orally twice a day; CLAR+APV, concomitant amprenavir and clarithromycin.