Skip to content

Fareston

Interactions

Toremifene/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 decreases the ability of your gut to process toremifene.

What might happen:

The amount of toremifene in your blood may increase. This may increase your risk of an irregular heartbeat, which may be life-threatening.

What you should do about this interaction:

While you are taking this medicine, you should avoid eating grapefruit 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 immediately discuss with doctor the effects of grapefruit on the blood levels of this medicine. If you notice an irregular heartbeat or have dizziness or fainting episodes, contact your doctor right away. Your doctor may want to perform an electrocardiogram (ECG) on you to see if the medicines are affecting your heart's rhythm.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.

References:

1.Fareston (toremifene citrate) US prescribing information. GTx, Inc. March, 2011.

2.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.

3.Kolars JC, Lown KS, Schmiedlin-Ren P, Ghosh M, Fang C, Wrighton SA, Merion RM, Watkins PB. CYP3A gene expression in human gut epithelium. Pharmacogenetics 1994 Oct;4(5):247-59.

4.Kivisto KT, Bookjans G, Fromm MF, Griese EU, Munzel P, Kroemer HK. Expression of CYP3A4, CYP3A5 and CYP3A7 in human duodenal tissue. Br J Clin Pharmacol 1996 Sep;42(3):387-9.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

More about Drugs and Medications

Newsletters

Subscribe to free WebMD newsletters.

  • WebMD Daily

    WebMD Daily

    Subscribe to the WebMD Daily, and you'll get today's top health news and trending topics, and the latest and best information from WebMD.

  • Men's Health

    Men's Health

    Subscribe to the Men's Health newsletter for the latest on disease prevention, fitness, sex, nutrition, and more from WebMD.

  • Women's Health

    Women's Health

    Subscribe to the Women's Health newsletter for the latest on disease prevention, fitness, sex, diet, anti-aging, and more from WebMD.

By clicking Submit, I agree to the WebMD Terms & Conditions & Privacy Policy

URAC: Accredited Health Web Site TRUSTe online privacy certification HONcode Seal AdChoices