Hormone replacement therapy for prevention and treatment of osteoporosis.

Estrogen therapy is clearly effective in the prevention and treatment of osteoporosis. Several estrogens and routes of administration are available. A progestin is required to protect the endometrium if the patient has a uterus. The duration of treatment required is unknown but probably is > or = 10 years for prevention and may be life-long, which is the requirement for patients with established disease. A regimen of patient monitoring can be easily established and must become routine for all patients on long-term treatment.