Grapefruit and grapefruit juice have the potential to interact with numerous drugs. A number of organic compounds, identified as furanocoumarin derivatives, interfere with the hepatic and intestinal enzyme cytochrome P450 isoform CYP3A4 and are therefore primarily responsible for the interaction. However, 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.