Effect of stopping different bone-sparing medications compared
6 December 2002
Postmenopausal women who take alendronate (Fosamax) for 2 years then stop maintain their bone mineral density (BMD) in the following year, US researchers have shown.
But women who take oestrogen (Premarin) for 2 years then stop see a reduction in BMD (Annals of Internal Medicine 2002; 137: 875-83).
The researchers conducted the first head-to-head study of its type to compare discontinuation of different bone-sparing therapies.
They looked at postmenopausal women aged from 44 to 77 years who had had a hysterectomy and had a T score at the lumbar (lower) spine of -2.0 SD or less.
(The T score is a standard measure used to indicate by how much a woman's bone density differs (in terms of standard deviation (SD) units) from an average score for a healthy adult woman. A score of 0 SD indicates no bone thinning; a score of -2.5 or less indicates osteoporosis.)
The 425 women were randomly allocated to receive either alendronate (10 mg daily), oestrogen (0.625 mg daily), both or placebo (an inactive medication) for 2 years.
In the third year, 244 women opted to take part in the discontinuation arm of the trial.
All women took calcium (500 mg daily) throughout.
Women taking alendronate or combination therapy who switched to placebo did not lose bone mass, while those who continued with combination therapy gained bone mass.
But women who switched from oestrogen to placebo lost bone mass at the spine, hip, femoral neck and trochanter (areas of the femur closest to the hip joint) at greater rates than did women who continued on placebo.
Women who took placebo (with calcium) maintained bone mass at the spine and hip.
The researchers acknowledged that the study was not large or long enough to show whether discontinuing oestrogen therapy was associated with more fractures than discontinuing either alendronate or combination therapy.
Merck Research Laboratories funded the trial.
Last Reviewed: 06 December 2002
- 1. Medical Observer Weekly 06/12/02
