Herb-drug interactions in nephrology: documented and theoretical.

Renal patients consuming herbal drugs are at risk for herb-drug interactions by various mechanisms. In transplant recipients, toxicity and underdosage of calcineurin inhibitor-based immunosuppression have been linked to phytochemically triggered activity changes of cytochrome P-450 isoenzyme CYP3A4 metabolism and drug transport proteins. This type of interaction might be triggered by many other plant products besides grapefruit juice and St. Johnâs wort, less well-known for this risk. Other potential herb-drug interactions in renal patients, for example with antidiabetics, anticoagulants or antihypertensives are discussed, although they have not yet been reported. Herb-drug interactions might possibly often go unnoticed, because physicians are not informed about herbal drug consumption by their patients. For better future detection and handling of herb-drug interactions, physicians should expand their knowledge about phytochemicals in herbs and foods.