Alendronate Interactions

Coffee (and orange juice) sharply reduce the absorption of alendronate, an oral bisphosphonate whose baseline absorption is already very low. Taking the tablet with coffee instead of plain water can cut the absorbed amount enough to make the dose ineffective for protecting bone.

Calcium binds alendronate in the gut and forms an insoluble complex, sharply reducing absorption of an already very poorly absorbed bisphosphonate. Taken together, the calcium can leave the osteoporosis drug clinically ineffective.