Alendronate is a member of the bisphosphonate family of drugs used to treat/prevent osteoporosis. It is also used to treat some bone diseases and some cases of cancer that have spread to bones.
Summary of Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem contradictory. For clarification, read the full article for details about the summarized interactions.
| Calcium Magnesium | |
| Depletion or interference | None known |
| Side effect reduction/prevention | None known |
| Supportive interaction | None known |
| Reduced drug absorption/bioavailability | None known |
| Adverse interaction | None known |
An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.
Interactions with Dietary Supplements
Calcium
Calcium supplements may interfere with alendronate absorption.1 However, one researcher suggested that addition of large amounts of supplemental calcium to alendronate therapy in patients with bone metastases (with evidence of osteomalacia) related to prostate cancer might improve the clinical outcome.2 Moreover, both calcium and alendronate are commonly used in the treatment of osteoporosis in the same people. To prevent potential interactions, alendronate should be taken two hours before or after calcium supplements.
Magnesium
Absorption of tiludronate, a drug related to alendronate, is reduced when taken with magnesium and/or aluminum-containing antacids.3 This interaction has not yet been reported with alendronate. Until more is known, alendronate should be taken two hours before or after magnesium and/or aluminum-containing antacids.
Interactions with Foods and Other Compounds
Food
Food, coffee, and orange juice significantly reduce absorption of alendronate.4
Alendronate should be taken with a large glass of plain water, upon arising in the morning, and 30 minutes or more before any food, beverages, supplements, or other medications.5 People taking alendronate should remain upright (do not lie down) for 30 minutes after taking the drug.6
References
1. Threlkeld DS, ed. Hormones, Bisphosphonates. InFacts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Jul 1998, 134r.
2. Adami S. Bisphosphonates in prostate carcinoma. Cancer 1997;80:1674–9.
3. Threlkeld DS, ed. Hormones, Bisphosphonates. InFacts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Jul 1998, 134r.
4. Gertz BJ, Holland SD, Kline WF, et al. Studies of the oral bioavailability of alendronate. Clin Pharmacol Ther 1995;58:288–98.
5. Threlkeld DS, ed. Hormones, Bisphosphonates. InFacts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Jul 1998, 134r.
6. Threlkeld DS, ed. Hormones, Bisphosphonates. InFacts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Jul 1998, 134r.
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2006-09-07


