Dolutegravir (DTG, GSK1349572) is an integrase inhibitor being developed for the treatment of human immunodeficiency virus (HIV)-1 infection by GlaxoSmithKline (GSK) on behalf of Shionogi-ViiV Healthcare LLC. DTG is metabolized primarily by uridine diphosphate glucuronyltransferase (UGT)1A1, with a minor role of cytochrome P450 (CYP)3A, and with renal elimination of unchanged drug being extremely low (< 1% of the dose). Fifty-three percent of the total oral dose is excreted unchanged in the feces but it is unknown if all or part of this is due to unabsorbed drug or some percentage of biliary excretion of the glucuronide conjugate which can be further degraded to form the parent compound in the gut lumen. The current Food and Drug Administration (FDA) draft guidance for renal impairment studies states that a pharmacokinetic (PK) study in patients with renal impairment should be conducted even for those drugs primarily metabolized or secreted in bile, because renal impairment can inhibit some pathways of hepatic and gut drug metabolism and transport.