OBJECTIVE

To determine the efficacy of alendronate (Fosamax) administration and withdrawal on the bone mineral density (BMD) in postmenopausal women with osteopenia and osteoporosis.

METHODS

Alendronate (10 mg) and calcium carbonate (containing calcium 500 mg) were administered daily to 25 Chinese menopausal women with osteopenia and osteoporosis for 6 months and to 15 women for 12 months. After the withdrawal of alendronate, calcium carbonate was administered continuously. Follow-up was made three times for the 6-month group: before treatment, 6 months after treatment, and 13 +/- 4 months (6 - 24 months) after aldoronate withdrawal, and was made four times for the 12-month group: before treatment, 6 months and 12 months after treatment, and 23 +/- 7 months (14 - 36 months) after alendronate withdrawal to determine the BMD of lumbar spine 2 approximately 4, neck of femur, Wards triangle, and greater trochanter and blood alkaline phosphatase (ALP).

RESULTS

Compared to the baseline value, the BMD in lumbar spine and hip increased significantly 6 months after treatment in 6-month group, with the BMD in lumbar spine 2 - 4 increased by 5.3% (P < 0.001). In the 6 month group, no significant decline was found in the BMD in lumbar spine and hip 13 +/- 4 months after alendronate withdrawal, the BMD in greater trochanter even increased further compared with that 6 months after treatment. In the 12-month group, the BMD significantly increased except in the Wards triangle after 6 months' treatment with an increase by 4.2% in lumbar spine 2 - 4 (P < 0.001). After 12 months' treatment the increment of BMD in lumbar spine 2 - 4 was 6.1% (P < 0.001) and the BMD of the hip remained unchanged. 23 +/- 7 months after the alendronte withdrawal the values of BMD in lumbar spine and hip were almost the same as that 12 months after treatment.

CONCLUSION

Alendronate increases the BMD in spine and hip, especially in lumbar spine. The skeletal benefits are maintained for at least 13 - 23 months in spine and hip after withdrawal of alendrenate.