INCREMENTS IN BONE-MINERAL DENSITY OF THE LUMBAR SPINE AND HIP AND SUPPRESSION OF BONE TURNOVER ARE MAINTAINED AFTER DISCONTINUATION OF ALENDRONATE IN POSTMENOPAUSAL WOMEN

PURPOSE: Previously we have reported a significant increase in bone mi neral density (BMD) of the spine and the hip and reductions in biochem ical indices of bone turnover in postmenopausal women with osteoporosi s treated with alendronate at various doses over 1 to 2 years. We have followed BMD and biochemical parameters in these patients for 1 or 2 years after discontinuation of alendronate to determine resolution of alendronate effects. PATIENTS AND METHODS: Participants received daily oral doses of placebo, 5 or 10 mg of alendronate for 2 years, or 20 o r 40 mg of alendronate for 1 year followed by 1 year of placebo. No tr eatment was given in the third year of study.RESULTS: Lumbar spine BMD changes in the 5- and 10-mg groups (-1.4 and -0.4%) were similar to t hose in the placebo group (-1.2%) 1 year after discontinuation of drug and lumbar spine BMD changes in the 20- and 40-mg groups (-1.2% and 0 .8%) were similar to those in the placebo group (-0.9%) 2 years after discontinuation of drug. BMD of the total hip followed the same patter n of resolution. The difference in BMD between alendronate and placebo groups at the end of alendronate treatment was maintained up to 2 yea rs. Residual reductions in the bone resorption markers urinary deoxypy ridinoline (D-Pyr) and collagen type 1 cross-linked N telopeptides and the bone formation markers serum bone-specific alkaline phosphatase a nd osteocalcin remained for 1 year after discontinuation of 5 and 10 m g of alendronate and for 2 years after discontinuation of 20 and 40 mg of alendronate, other than return of D-Pyr to baseline 1 year after c essation of treatment with the 5- and 10-mg doses. CONCLUSIONS: A resi dual decrease in bone turnover may be found up to 2 years after discon tinuation of alendronate. Accelerated bone loss is not observed when t reatment is discontinued. However, continuous therapy with alendronate is required to achieve a continuous gain in BMD. (C) 1997 by Excerpta Medica, Inc.