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.
Very important. A change in your diet, medicine, or dosage may be necessary. Promptly consult your doctor or pharmacist.
How the interaction occurs:
When grapefruit or grapefruit juice is taken with you calcium channel blocker medicine, it may increase the amount of the medicine absorbed into your bloodstream.
What might happen:
Your blood levels of this medicine may increase. Increased blood levels may cause a lower-than-desired blood pressure or an undesirable change in heart rate.
What you should do about this interaction:
While you are taking this medicine, do not eat grapefruit or drink grapefruit juice at any time. 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 immediately discuss with your doctor the effects of grapefruit on the blood levels of this medicine.Tell your doctor immediately if symptoms of low blood pressure (such as rapid heartbeat or dizziness) occur. Also report an irregular or unusually slow heartbeat. Contact your healthcare professional for more information.Your healthcare professional may be aware of this interaction and may be monitoring you for it. Do not start, stop, or change your medicine or diet before checking with them first.
1.Sigusch H, Hippius M, Henschel L, Kaufmann K, Hoffmann A. Influence of grapefruit juice on the pharmacokinetics of a slow release nifedipine formulation. Pharmazie 1994 Jul;49(7):522-4.
2.Miniscalco A, Lundahl J, Regardh CG, Edgar B, Eriksson UG. Inhibition of dihydropyridine metabolism in rat and human liver microsomes by flavonoids found in grapefruit juice. J Pharmacol Exp Ther 1992 Jun;261(3):1195-9.
3.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.
4.Bailey DG, Arnold JM, Strong HA, Munoz C, Spence JD. Effect of grapefruit juice and naringin on nisoldipine pharmacokinetics. Clin Pharmacol Ther 1993 Dec;54(6):589-94.
5.Grapefruit juice interactions with drugs. Med Lett Drugs Ther 1995 Aug 18; 37(955):73-4.
6.Bailey DG, Malcolm J, Arnold O, Spence JD. Grapefruit juice-drug interactions. Br J Clin Pharmacol 1998 Aug;46(2):101-10.
7.Josefsson M, Zackrisson AL, Ahlner J. Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers. Eur J Clin Pharmacol 1996;51(2):189-93.
8.Vincent J, Harris SI, Foulds G, Dogolo LC, Willavize S, Friedman HL. Lack of effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of amlodipine. Br J Clin Pharmacol 2000 Nov;50(5):455-63.
9.Lundahl J, Regardh CG, Edgar B, Johnsson G. Relationship between time of intake of grapefruit juice and its effect on pharmacokinetics and pharmacodynamics of felodipine in healthy subjects. Eur J Clin Pharmacol 1995;49(1-2):61-7.
10.Bailey DG, Spence JD, Munoz C, Arnold JM. Interaction of citrus juices with felodipine and nifedipine. Lancet 1991 Feb 2;337(8736):268-9.
11.Dresser GK, Bailey DG, Carruthers SG. Grapefruit juice--felodipine interaction in the elderly. Clin Pharmacol Ther 2000 Jul;68(1):28-34.
12.Lundahl JU, Regardh CG, Edgar B, Johnsson G. The interaction effect of grapefruit juice is maximal after the first glass. Eur J Clin Pharmacol 1998 Mar;54(1):75-81.
13.Soons PA, Vogels BA, Roosemalen MC, Schoemaker HC, Uchida E, Edgar B, Lundahl J, Cohen AF, Breimer DD. Grapefruit juice and cimetidine inhibit stereoselective metabolism of nitrendipine in humans. Clin Pharmacol Ther 1991 Oct;50(4):394-403.
14.Takanaga H, Ohnishi A, Murakami H, Matsuo H, Higuchi S, Urae A, Irie S, Furuie H, Matsukuma K, Kimura M, Kawano K, Orii Y, Tanaka T, Sawada Y. Relationship between time after intake of grapefruit juice and the effect on pharmacokinetics and pharmacodynamics of nisoldipine in healthy subjects. Clin Pharmacol Ther 2000 Mar;67(3):201-14.
15.Fuhr U, Maier-Bruggemann A, Blume H, Muck W, Unger S, Kuhlmann J, Huschka C, Zaigler M, Rietbrock S, Staib AH. Grapefruit juice increases oral nimodipine bioavailability. Int J Clin Pharmacol Ther 1998 Mar; 36(3):126-32.
16.Pisarik P. Blood pressure-lowering effect of adding grapefruit juice to nifedipine and terazosin in a patient with severe renovascular hypertension. Arch Fam Med 1996 Jul-Aug;5(7):413-6.
17.Uno T, Ohkubo T, Sugawara K, Higashiyama A, Motomura S, Ishizaki T. Effects of grapefruit juice on the stereoselective disposition of nicardipine in humans: evidence for dominant presystemic elimination at the gut site. Eur J Clin Pharmacol 2000 Dec;56(9-10):643-9.
18.Adigun AQ, Mudasiru Z. Clinical effects of grapefruit juice-nifedipine interaction in a 54-year-old Nigerian: a case report. J Natl Med Assoc 2002 Apr;94(4):276-8.