Originally published as JCO Early Release 10.1200/JCO.2009.21.3629 on January 26 2009

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Magnesium Supplements for Menopausal Hot Flashes

The Massey Cancer Center, Virginia Commonwealth University, Richmond, VA

To the Editor:

Hot flashes are common with natural menopause or induced estrogen deficiency from chemotherapy, tamoxifen, raloxifene, or the aromatase inhibitors. As many as 90% of perimenopausal women have hot flashes,¹ and 40% of survivors of breast cancer rate their hot flashes rate the effect as "quite a bit" to "severe".² While some women are not affected, others have significant sleep deprivation and distress.

Several treatments have proven effective including selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, medroxyprogesterone, and megestrol acetate,³ but all have potential adverse effects. Antidepressants can cause mental, emotional, and physical adverse effects. Megestrol acetate and medroxyprogesterone acetate, while effective, can potentially cause fluid retention, premenstrual symptoms, and deep vein thrombosis.

Recently I saw two patients with breast cancer who volunteered that when they began magnesium supplements for reasons other than hot flashes, their hot flashes diminished within 24 hours and had not returned. In each case, the person was not expecting any relief from magnesium, so placebo effect is unlikely.

J.K. is a 68-year-old woman diagnosed with stage II estrogen receptor– and progesterone receptor–negative breast cancer in July 2007. She was treated with mastectomy, chemotherapy, and trastuzamab. Her hot flashes worsened to hourly (24 per day) of moderate severity that interfered with sleep and drenched her nightclothes. Venlafaxine⁴ and citalopram⁵ were minimally helpful. She prepared for a routine colonoscopy with 300 mls of magnesium citrate, and that night had no hot flashes at all. Subsequently, she used over the counter magnesium 250 mg, and then 400 mg, with reduction in her hot flashes to three or four a day of mild severity that did not interrupt her life or sleep or cause drenching sweats. She categorized her hot flashes as very bothersome before magnesium and not bothersome after magnesium. Her sleep and overall well-being improved (J.K., personal communication, December 3, 2008).

G.F. is a 54-year-old woman who went into natural menopause at age 52, referred for early-stage breast cancer. She had hot flashes each night (three or four per night, less common during the day) that interfered with her sleep. She watched "Dr. Phil" on TV, and the guest suggested a combination of Vitamin D at 400 U, calcium at 1,200 mg, and magnesium at 600 mg for weight loss (the purported mechanism was to turn fats into soaps that would not be absorbed). She began these supplements, and overnight her hot flashes diminished to half their frequency and severity. She also described her prior hot flashes as very bothersome, and nonexistent after beginning the regimen (G.F., personal communication, December 5, 2008).

Magnesium has been used for years to treat hypertension,⁶ eclampsia,⁷ and other cardiovascular or nerve disorders.⁸ It has been reported to help with hot flashes on many Web sites. However, there are no reports in the medical literature that show effectiveness. Magnesium is the fourth most common mineral in the human body. Only approximately 1% of total body stores is in the blood, and serum levels are tightly regulated through uptake, then renal and fecal excretion. Recommended daily oral intake is 310 to 350 mg of magnesium.⁹ In general, magnesium is a safe supplement. There are no known reported cases of excess dietary magnesium causing harm. Excess supplemental magnesium can cause diarrhea and cramping. There is one case report of a young woman with severe hypermagnesemia due to excess antacid therapy after bone marrow transplant, with five times the normal serum levels, that caused unresponsiveness.¹⁰ The "signs of excess magnesium can be similar to magnesium deficiency and include changes in mental status, nausea, diarrhea, appetite loss, muscle weakness, difficulty breathing, extremely low blood pressure, and irregular heartbeat."⁹ The upper levels of supplemental magnesium for men and women are 350 mg/day. Physicians may prescribe higher doses for treatment of osteoporosis, diabetes, cardiac conditions, and various neurologic conditions. Since magnesium levels are tightly controlled by the body, excess is excreted in the urine and stool.

A natural, inexpensive, readily available treatment would be helpful to many women and men undergoing hot flashes. A pilot trial of magnesium oxide supplements is planned according to the protocol outlined by Loprinzi et al.¹¹

AUTHOR'S DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

The author(s) indicated no potential conflicts of interest.

REFERENCES

1. Feldman BM, Voda A, Gronseth E: The prevalence of hot flash and associated variables among perimenopausal women. Res Nurs Health 8:261–268, 1985.[Medline]

2. Carpenter JS, Andrykowski MA: Menopausal symptoms in breast cancer survivors. Oncol Nurs Forum 26:1311–1317, 1999.[Medline]

3. Bordeleau L, Pritchard K, Goodwin P, et al: Therapeutic options for the management of hot flashes in breast cancer survivors: An evidence-based review. Clin Ther 29:230–241, 2007.[CrossRef][Medline]

4. Loprinzi CL, Kugler JW, Sloan JA, et al: Venlafaxine in management of hot flashes in survivors of breast cancer: A randomised controlled trial. Lancet 356:2059–2063, 2000.[CrossRef][Medline]

5. Loprinzi CL, Flynn PJ, Carpenter LA, et al: Pilot evaluation of citalopram for the treatment of hot flashes in women with inadequate benefit from venlafaxine. J Palliat Med 8:924–930, 2005.[CrossRef][Medline]

6. Houston MC, Harper KJ: Potassium, magnesium, and calcium: Their role in both the cause and treatment of hypertension. J Clin Hypertens (Greenwich) 10:3–11, 2008 (Suppl 2.[CrossRef][Medline]

7. Sibai BM: Diagnosis and management of gestational hypertension and preeclampsia. Obstet Gynecol 102:181–192, 2003.[CrossRef][Medline]

8. Gums JG: Magnesium in cardiovascular and other disorders. Am J Health Syst Pharm 61:1569–1576, 2004.[Abstract/Free Full Text]

9. National Institutes of Health. What are some of the current issues and controversies about magnesium? 2005 http://ods.od.nih.gov/factsheets/magnesium.asp#h7.

10. Jaing T-H, Hung I-H, Chung H-T, et al: Acute hypermagnesemia: A rare complication of antacid administration after bone marrow transplantation. Clin Chim Acta 326:201–203, 2002.[CrossRef][Medline]

11. Sloan JA, Loprinzi CL, Novotny PJ, et al: Methodologic lessons learned from hot flash studies. J Clin Oncol 19:4280–4290, 2001.[Abstract/Free Full Text]

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This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Smith, T. J. Search for Related Content PubMed PubMed Citation Articles by Smith, T. J. Social Bookmarking                            What's this?