High Quality Content by WIKIPEDIA articles! Grapefruit and grapefruit juice have the potential to interact with numerous drugs. Organic compounds, furanocoumarin derivatives, interfere with the hepatic and intestinal enzyme cytochrome P450 isoform CYP3A4 and are believed to be primarily responsible for the effects. Bioactive compounds in grapefruit juice may also interfere with P-glycoprotein and organic anion transporting polypeptides (OATPs) either increasing or decreasing bioavailability of a number of drugs. Pomelo (the Asian fruit which was crossed with an orange to produce grapefruit) also contains high amounts of furanocoumarin derivatives. Some grapefruit-pomelo hybrids have practically no furanocoumarin content, and one is a commercially viable seedless type.