In a mass balance/ excretion study in eight healthy male volunteers dosed to steady state with nevirapine 200 mg given twice daily followed by a single 50 mg dose of 14C-nevirapine, approximately 91.4 ± 10.5% of the radiolabelled dose was recovered, with urine (81.3 ± 11.1%) representing the primary route of excretion compared to faeces (10.1 ± 1.5%).