New drug looks promising for reducing osteoporosis risk

ON CALL

October 30, 1990|By Dr. Simeon Margolis

Q: It is more than 10 years since my menopause. I have never been on replacement hormones and my doctor has told me I am at high risk for a fracture of my vertebrae because they are very thin. Is it true there is a new treatment for osteoporosis that may help me?

A: A recent article in the New England Journal of Medicine reported the results of a study carried out in seven different centers on 423 women who averaged 65 years of age and 18 years after menopause. All the women had already suffered at least one backbone fracture and thinned backbones on X-ray. They were divided into two groups and treated for two years with either a placebo or etidronate (Didronel), a drug that blocks the reabsorption of bone.

Compared with the control groups, those treated with etidronate had only half the number of vertebral fractures during the two years of the study. The rate of fractures was reduced even more (by two-thirds) in the groups of etidronate-treated subjects who started out with the thinnest bones. In addition, those treated with etidronate had a significant increase in the density of their spinal bones. The drug had no beneficial effect on the number of fractures or the density of the hip or waist bones, which are

composed of a different type of bone from the vertebrae. Etidronate was well tolerated with no significant side effects.

These findings are quite promising. Further studies are in progress to determine whether the favorable effects and the lack of adverse reactions are maintained for periods longer than two years.

Q: For almost a year I have had chest pain when I exert myself. The doctor said I have angina. An arteriogram of my coronary arteries has been done and now my doctor has recommended a thallium scan. Can you explain this procedure? What does it show and how much will it cost?

A: Obtaining a thallium scan or image involves the intravenous injection of a radioactive isotope of the element thallium, usually at the peak of exercise.

Thallium is rapidly removed from the blood by the cells of the heart muscle (myocardium). Sensitive devices detect radioactivity within the heart muscle and thus the distribution of the thallium. The absence of radioactivity in a segment of the myocardium signals areas of the heart that have died or become scarred by the lack of a blood supply.

Slow uptake of the radioactive thallium occurs in ischemic portions of the myocardium (where the blood supply gets through but not easily).

In short, thallium imaging measures the status of the heart muscle itself while coronary angiography examines the health of the coronary arteries.

Thallium scanning is valuable for diagnosing the extent of permanent heart damage and predicting subsequent heart attacks, because this risk increases with the number and size of the oxygen-starved segments of myocardium.

A thallium scan costs about $1,000.

Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for academic affairs at the school.

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