Estrogen for osteoporosis

Examples

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Women can take estrogen by:

• Taking a pill every day. These include:
  • Conjugated estrogen (for example, Premarin).
  • Esterified estrogen (for example, Menest).
  • Estradiol (for example, Estrace).
  • Ethinyl estradiol (for example, Estinyl).

• Using an adhesive patch. Options include:
  • Climara (applied to the skin once a week).
  • Estraderm (applied to the skin 1 to 2 times a week).
  • Menostar (a lower-dose estrogen patch, applied to the skin once a week).
  • Vivelle (applied to the skin 2 times a week).

How It Works

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Taking estrogen increases a woman's levels of the hormone estrogen after menopause. Estrogen slows bone thinning and causes some increase in bone thickness.

Why It Is Used

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Estrogen is used to prevent osteoporosis in women after menopause. It may also be used to slow bone loss in women who have osteoporosis.

How Well It Works

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Estrogen has been shown to prevent bone loss and lower the risk of hip fractures in postmenopausal women.¹

Side Effects

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The side effects of estrogen include:

• Headache.
• Holding fluid in the body (fluid or water retention).
• Weight gain caused by fluid retention.
• Swollen breasts.

The Women's Health Initiative (WHI) study linked the use of ERT to an increase in a woman's risk of stroke. Many experts recommend that long-term estrogen replacement therapy only be considered for women with a significant risk for osteoporosis that outweighs the risks of taking HRT.^{2 1} To learn more about this study, see WHI: Risks and benefits of taking ERT.

Estrogen should be taken at the lowest dose and for the shortest duration possible. Women who have side effects from taking estrogen need to report them to a health professional.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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Researchers are studying the effects of low-dose estrogen on women age 65 and older. An early, small study indicates that a low estrogen dose (one-quarter that of conventional ERT) may provide the same benefit—increased bone density and decreased fractures—as the higher dose. In the same study, about one-third of the women were given the low estrogen dose and progesterone (because these women had not had hysterectomies). This group of women also experienced increased bone density. However, the long-term risks of taking low-dose estrogen (and progesterone in one-third of the cases) were not studied and are unclear.³

Estrogen may be used along with bisphosphonate medicines that prevent bone loss. Bisphosphonate medicines include risedronate (Actonel) or alendronate (Fosamax). Studies show that taking a bisphosphonate with hormone therapy results in increased bone mass when compared to taking either a bisphosphonate or hormone therapy alone.^{4 5}

Estrogen alone is prescribed only for a woman who has had her uterus removed (hysterectomy), because taking estrogen increases a woman's risk for developing endometrial cancer. Adding another hormone, progesterone, lowers this risk but may have additional risks that you should discuss with your doctor.

Women who have certain conditions, such as liver or gallbladder disease and high amounts of certain fats (triglycerides) in their blood, often use the estrogen patch rather than take estrogen in pill form. This helps prevent some side effects that may occur from taking the pill form. Even low doses of estrogen seem to have a beneficial effect on bones.

You should not take estrogen if you have been diagnosed with any of the following conditions:

• Uterine bleeding
• Uterine cancer
• Breast lumps that have not yet been diagnosed
• Breast cancer (now or in the past)
• A family history (mother, sister, daughter, or two or more other close relatives, such as cousins) of breast cancer
• An increased risk of developing blood clots

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. Women's Health Initiative Steering Committee (2004). Effects of conjugated equine estrogen in postmenopausal women with hysterectomy. JAMA, 291(14): 1701–1712.

2. National Heart, Lung, and Blood Institute (2004). Questions and answers about the WHI postmenopausal hormone therapy trials. Available online: http://www.nhlbi.nih.gov/whi/whi_faq.htm.

3. Prestwood KM, et al. (2003). Ultralow-dose micronized 17 B-estradiol and bone density and bone metabolism in older women. JAMA, 290(8): 1042–1048.

4. Harris ST, et al. (2001). Effect of combined risedronate and hormone replacement therapies on bone mineral density in postmenopausal women. Journal of Clinical Endocrinology and Metabolism, 86(5): 1890–1897.

5. Greenspan SL, et al. (2003). Combination therapy with hormone replacement and alendronate for prevention of bone loss in elderly women. JAMA, 289(19): 2525–2533.

Credits

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Author	Shannon Erstad, MBA/MPH
Editor	Kathleen M. Ariss, MS
Associate Editor	Pat Truman, MATC
Primary Medical Reviewer	Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer	Kirtly Jones, MD - Obstetrics and Gynecology
Last Updated	November 21, 2008