Dear Dr. Roach: I’m a 72-year-old female and have been taking Aldactone for several years for hair loss. I started losing hair when I was 55 years old. I read an article about Aldactone in a magazine and asked my primary doctor about the drug. He said I could try it. He started me at 25 mg and it worked. Now I’m on 100 mg, because over the years I needed more for it to be effective.

Please tell me the pros and cons of this drug. I’m afraid to stop and see what will happen. I don’t have any side effects other than being a little lightheaded right after I take the pill in the morning. — V.C.

Answer: Spironolactone (Aldactone) is a commonly used diuretic. It is often used because unlike most diuretics, which lower blood potassium levels, spironolactone usually raises them. It has also been shown to be useful in some people with heart failure. However, it also blocks an androgen receptor and blocks the formation of testosterone. It is therefore used in some cases of female pattern hair loss. The most commonly used dose is 200 mg. It is effective in about half of women who try it.

Because of its diuretic effect, it can cause some lightheadedness. Potassium levels should be checked periodically. Some women will notice a decreased libido due to the decrease in androgens, and headache can be a problem. Women who still have their periods may notice irregularities.

My experience is that hair loss is such an important cosmetic issue for both men and women that they are often willing to put up with some side effects for effective treatment.