Effect of chronic carbonic anhydrase inhibitor therapy on bone mineral density in white women.

A limited, dual-photon absorptiometry, single-center study of bone mineral density (BMD) was conducted on white female glaucoma subjects who were chronic users of the carbonic anhydrase (CA) inhibitors acetazolamide (Az) or methazolamide (Mz). In postmenopausal subjects long-term (greater than 4 years) CA inhibitor use was associated with a bone-sparing effect as judged by spinal BMD in comparison to controls matched for age, sex, weight, and ethnic group or in comparison to a national normative data base. Short-term (0-2 years) postmenopausal CA inhibitor users and premenopausal subjects using CA inhibitors showed no sparing of spinal BMD. Femoral neck BMD was not affected by CA inhibitor therapy in any of the groups. This study supports a proposed role for carbonic anhydrase in human bone resorption and suggests a possible future utility for carbonic anhydrase inhibitors in prophylaxis or management of primary involutional osteoporosis. Future studies are necessary to verify and expand these findings, assess the effects of CA inhibitors on bone mechanical competence, and further develop CA inhibitors with some specificity for bone.