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Nifedipine

Also indexed as: Adalat®, Procardia®

Combination drugs: Beta-Adalat®, Tenif®

Nifedipine is a calcium channel blocker used to treat angina pectoris and high blood pressure.

Interactions with Herbs

Pleurisy root
As pleurisy root and other plants in the Aesclepius genus contain cardiac glycosides, it is best to avoid use of pleurisy root with heart medications such as calcium channel blockers.1

Interactions with Foods and Other Compounds

Grapefruit juice
Ingestion of grapefruit juice has been shown to increase the absorption of felodipine (a drug similar in structure and action to that of nifedipine) and to increase the adverse effects of the medication in patients with hypertension. People taking nifedipine or similar drugs should not consume grapefruit juice or grapefruit, unless they have discussed it with their physician.2

Food
Nifedipine may be taken with or without food.3 Nifedipine products should be swallowed whole, without crushing or chewing.4

Tobacco
In a double-blind study of ten cigarette smokers with angina treated with nifedipine for one week, angina episodes were significantly reduced during the nonsmoking phase compared to the smoking phase.5 People with angina taking nifedipine should not smoke tobacco.

Summary of Interactions for Nifedipine

Depletion or interference None known
Adverse interaction Pleurisy root*
Tobacco*
Side effect reduction/prevention None known
Supportive interaction None known
Reduced drug absorption/bioavailability None known
Other (see text) Grapefruit juice

For the convenience of the reader, the information in the summary is categorized as follows: “Depletion or interference” indicates the drug may deplete or interfere with the absorption or function of the supplement or herb. “Adverse interaction” indicates that the supplement or herb used together with the drug may result in undesirable effects. “Side effect reduction/prevention” indicates the supplement or herb may reduce the likelihood and/or severity of a potential side effect caused by the drug. “Supportive interaction” indicates the supplement or herb may support or aid the function of the drug. “Reduced drug absorption/bioavailability” indicates that the supplement or herb may decrease the absorption and/or activity of the drug in the body. An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

References:

1. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for Health-Care Professionals. London: Pharmaceutical Press, 1996, 213–4.

2. Bailey DG, Malcolm J, Arnold O, Spence JD. Grapefuit Juice-Drug Interactions. Br J Clin Pharmacol 1998;46:101–110.

3. Reitberg DP, Love SJ, Quercia GT, Zinny MA. Effect of food on nifedipine pharmacokinetics. Clin Pharmacol Ther 1987;42:72–5.

4. Threlkeld DS, ed. Diuretics and Cardiovasculars, Calcium Channel Blocking Agents. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Mar 1996, 149m–9n.

5. Deanfield J, Wright C, Krikler S, et al. Cigarette smoking and the treatment of angina with propranolol, atenolol, and nifedipine. N Engl J Med 1984;310:951–4.