CGMP Specific PDE Type-5 Inhibitors/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.
Important. Possible changes in your diet, medicine, or dosage should be discussed with your doctor or pharmacist.
How the interaction occurs:
Grapefruit juice decreases the ability of your gut to process sildenafil, tadalafil, and vardenafil.
What might happen:
The level of this drug can increase in your blood and cause more side effects than usual.
What you should do about this interaction:
While you are taking this medicine, you should avoid eating grapefruit or drink 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 immediately discuss with doctor the effects of grapefruit on the blood levels of this medicine. If you notice an increase in any side effect from your medicine, contact your doctor. Your healthcare professionals 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.Lown KS, Bailey DG, Fontana RJ, Janardan SK, Adair CH, Fortlage LA, Brown MB, Guo W, Watkins PB. Grapefruit juice increases felodipine oral availability in humans by decreasing intestinal CYP3A protein expression. J Clin Invest 1997 May 15;99(10):2545-53.
2.Jetter A, Kinzig-Schippers M, Walchner-Bonjean M, Hering U, Bulitta J, Schreiner P, Sorgel F, Fuhr U. Effects of grapefruit juice on the pharmacokinetics of sildenafil. Clin Pharmacol Ther 2002 Jan;71(1):21-9.
3.Cialis (tadalafil) US prescribing information. Eli Lilly and Company March 31, 2005.
4.Cialis (tadalafil) UK summary of product characteristics. Eli Lilly and Company Limited December 22, 2004.
5.Levitra (vardenafil) UK summary of product characteristics. Bayer plc. June 17, 2004.
6.Levitra (vardenafil) Canadian prescribing information. Bayer March 10, 2004.
7.Lee M, Min DI. Determination of sildenafil citrate in plasma by high-performance liquid chromatography and a case for the potential interaction of grapefruit juice with sildenafil citrate. Ther Drug Monit 2001 Feb;23(1):21-6.