Bone mineral content of women receiving tamoxifen for mastalgia.

Dual photon absorptiometry (DPA) has been used to measure the effect of short and medium-term administration of tamoxifen on bone density in the axial skeleton of women with mastalgia. This provided a unique opportunity to monitor the effect of this 'anti-oestrogenic' agent in predominantly premenopausal women, not suffering from malignancy. In addition, plasma levels of calcium, phosphate, alkaline phosphatase and serum levels of oesteocalcin (GLA) have been assayed, both before and after 3 months of starting either tamoxifen or placebo treatment. No significant alterations in bone density were seen. Osteocalcin, alkaline phosphatase and electrolytes were unchanged and there was no dose response observed in women receiving either 10 mg or 20 mg of tamoxifen. Although possessing anti-oestrogenic properties, tamoxifen is also a partial agonist. Administration for the short periods does not measurably influence spinal or femoral bone density and thus the agent can probably be given safely for the short-term treatment of mastalgia.