Diltiazem/Grapefruit Juice
This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug, changing your diet or commencing any course of treatment.
Medical warning:
Very important. A change in your diet, medicine, or dosage may be necessary. Promptly consult your doctor or pharmacist.
How the interaction occurs:
Grapefruit juice may increase the amount of diltiazem your body absorbs.
What might happen:
When diltiazem is taken with grapefruit juice, the grapefruit juice causes the diltiazem to build up in your body. This increased amount of diltiazem will have a greater effect of both desired and undesired effects.
What you should do about this interaction:
While you are taking this medicine, you should avoid eating grapefruit or or drinking grapefruit juice. You may choose an alternative citrus beverage (such as orange juice). In the event that you are instructed by a healthcare professional (e.g., doctor, pharmacist, or dietitian) to eat grapefruit or drink grapefruit juice you should discuss with your doctor the effects of graprefruit on the blood levels of this medicine. These effects can occur even if grapefruit is not consumed at the same time of the diltiazem dose This interaction may occur at any time in your treatment with diltiazem if grapefruit or grapefruit juice is consumed.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
References:
1.Christensen H, Asberg A, Holmboe AB, Berg KJ. Coadministration of grapefruit juice increases systemic exposure of diltiazem in healthy volunteers. Eur J Clin Pharmacol 2002 Nov;58(8):515-20.
2.Wangensteen H, Molden E, Christensen H, Malterud KE. Identification of epoxybergamottin as a CYP3A4 inhibitor in grapefruit peel. Eur J Clin Pharmacol 2003 Feb;58(10):663-8.
3.Bailey DG, Dresser GK. Interactions between grapefruit juice and cardiovascular drugs. Am J Cardiovasc Drugs 2004;4(5):281-97.
4.Sigusch H, Henschel L, Kraul H, Merkel U, Hoffmann A. Lack of effect of grapefruit juice on diltiazem bioavailability in normal subjects. Pharmazie 1994 Sep;49(9):675-9.
