Grape

Are there any interactions with medications?

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Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Some medications are changed and broken down by the liver. Grape juice might increase how quickly the liver breaks down some medications. Taking grape along with some medications that are changed by the liver can decrease the effectiveness of these medications. Before taking grape, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline, zileuton (Zyflo), zolmitriptan (Zomig), and others.

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Phenacetin
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

The body breaks down phenacetin to get rid of it. Drinking grape juice might increase how quickly the body breaks down phenacetin. Taking phenacetin along with grape juice might decrease the effectiveness of phenacetin.

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Warfarin (Coumadin)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Warfarin (Coumadin) is used to slow blood clotting. Grape seed might also slow blood clotting. Taking grape seed along with warfarin (Coumadin) might increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Dosing considerations for Grape.

The following doses have been studied in scientific research:

BY MOUTH:

• For poor blood flow in the legs (chronic venous insufficiency):
• Standardized red vine grape extract AS 195 (Antistax, Boehringer Ingelheim 360 mg or 720 mg once daily.
• Grape seed extract as tablets or capsules dosed at 75-300 mg daily for three weeks followed by a maintenance dose of 40-80 mg daily.
• Grape seed extract proanthocyanidin doses of 150-300 mg per day. Proanthocyanidin is one of the active ingredients in grape.
• For reducing eye stress due to glare: Grape seed extract proanthocyanidin doses of 200-300 mg per day.