Tamoxifen and hypercalcaemia. A case report.

A patient is reported in whom hypercalcaemia developed when adjuvant hormonal treatment with tamoxifen (Nolvadex) was instituted. The response to withdrawal of the drug and the recurrence of hypercalcaemia on rechallenge with tamoxifen make a causal relationship between hypercalcaemia and tamoxifen therapy probable. Some of the mechanisms of development of hypercalcaemia in cases of breast carcinoma are discussed, and the literature on hypercalcaemia and tamoxifen therapy is reviewed.