Dear Dr. Roach: Does taking Norvasc or any calcium channel blocker reduce or destroy the calcium in the bones, eventually causing osteoporosis? — E.G.

Answer: No. Calcium channel blockers, like amlodipine (Norvasc), work on cells in the heart and blood vessels, controlling the flow of calcium into the cell. Calcium in the cell is one of the regulators of smooth muscle cells, and for Norvasc in particular, that means its major effect is on blood vessels, causing them to open up and reduce blood pressure, and thus the amount of work the heart needs to do.

Calcium in bone is used structurally, where it combines with other ions to form hydroxyapatite, the mineral that keeps bones hard and strong. The mechanism for calcium entry into bone cells is very different. Calcium channel blockers do not affect mineralization of the bone, nor do they increase the risk for osteoporosis.

One group found that people on calcium channel blockers may have a slightly higher risk of fractures; however, that was thought to be due to an increased number of falls, especially in the elderly. Physicians need to take care not to use too much medication, especially ones that dilate blood vessels, as they can increase risk of dizziness and falls.

Readers: The booklet on hepatitis explains the three different kinds. Readers can obtain a copy by writing:

Dr. Roach

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