Grapefruit and other related citrus, like Seville oranges, tangelos, minneolas and pummelos, contain furanocoumarins -- a group of compounds that interfere with the intestinal absorption of many drugs. Decreased absorption can persist for up to 72 hours after you have eaten the fruit, its juice or an extract of the fruit. Decreased absorption may sound as if the biggest risk that grapefruit poses is reduced drug efficacy, but it can actually result in higher levels of the pharmaceutical persisting in your bloodstream. Increased blood levels of your drugs may result in increased therapeutic effects, adverse side effects or even toxicity.
Adalat and Grapefruit
Adalat is one of the brand names of nifedipine, which is also sold as Adalat CC, Procardia, Procardia XL, Nifedipine ER and Nifedical XL. These drugs are prescribed for patients with hypertension or angina and function as calcium channel blockers. You should not take Adalat or any of the other members of the nifedipine family with grapefruit or related citrus fruits or juices. Eating or drinking from the grapefruit family at any time while you are on one of these drugs has the potential to interfere with the absorption and functioning of the drug.
Other Adalat Interactions
While you are taking Adalat, you should avoid eating natural licorice, which is also known as glycyrrhiza glabra. Two or more twists of natural licorice candy per day can increase sodium absorption and potassium excretion, resulting in higher blood pressure. Increasing your blood pressure antagonizes the efforts of your antihypertensive drug regimen and may result in dangerously low levels of potassium in your blood. Ginger, ginkgo, ginseng, St. John's wort and melatonin can also interfere with Adalat and should not be taken while you are taking any version of nifedipine. As with most drugs, you should also avoid alcohol while you are taking Adalat.
Maxzide and Grapefruit
Maxzide is one of the brand names of triamterene, which is also sold as Dyrenium and Diazide. In addition to triamterene, Maxzide and Diazide also contain hydrochlorothiazide. Both triamterene and hydrochlorothiazide are diuretics -- a therapy often combined with antihypertensive medication. Triameterene is a potassium-sparing diuretic and hydrochlorothiazide is a potassium-depleting diuretic. Neither of these drugs has been shown to be impacted by grapefruit or related citrus, so if you are taking only this medication, you should be safe eating grapefruit. If, like many patients, you are concurrently taking Maxzide and an antihypertensive -- which is impacted by grapefruit -- you should still abstain from grapefruit-related citrus products.
Other Maxzide Interactions
Maxzide should not be taken with supplemental potassium or with salt substitutes. Your doctor may recommend a sodium- and calcium-restricted diet, depending upon your specific situation. Avoid natural licorice while you are taking Maxzide.
Consult Your Physician
The information that you find in this article or any other informative article should not be substituted for your physician's advice. Please consult your doctor with questions that you have regarding your medical care and medications -- both prescription and over the counter.
References
- "Food & Medication Interaction, 15th Edition"; Zaneta M. Pronsky; 2008
- "Nutrition and Diagnosis-Related Care: Sixth Edition"; Sylvia Escott-Stump; 2008
- "Krause's Food and Nutrition Therapy: 12th Edition"; L. Kathleen Mahan and Sylvia Escott-Stump; 2008
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