Blood pressure drug reduces bone density in study

CHICAGO (Reuters) - Powerful diuretics used to control blood pressure can also steal calcium from the bones and cause significant bone loss in men who take them, researchers reported on Monday.

Older men who used the drugs the most had triple the bone loss of men who never used them, the researchers reported in the Archives of Internal Medicine.

They found a direct correlation between use of the drugs and bone loss in men -- putting them at risk of osteoporosis, which can cause broken hips and other broken bones.

Though osteoporosis is more common in women than men, one in five Americans with the bone-weakening condition is a man -- and as many as 2 million American men suffer from it.

Doctors should keep an eye out for this problem in men taking the drugs, said Dr. Lionel Lim of Griffin Hospital, in Derby, Connecticut, who led the study.

One of the most common brand names is Lasix, and these so-called loop diuretics are also sold under the generic name furosemide. Diuretics work to lower blood pressure by removing water from the blood via the kidneys.

With less blood circulating, the blood does not have to pump so hard. The kidneys also filter out more sodium, potassium and, evidently, calcium. The drugs are especially effective in patients with heart failure, relieving the characteristic swollen ankles and breathlessness.

Lim studied nearly 3,300 men aged 65 and older, about 8 percent of whom had taken the drugs either regularly or from time to time.

Lim's team measured the men's hip bone density at the start and again roughly 4-1/2 years later.

Bone loss averaged 0.78 percent annually among the 84 men who used loop diuretics regularly, compared to 0.33 percent among non-users and 0.58 percent among the 181 intermittent users.

Previous studies have associated diuretic use with a patient's risk of breaking a hip or fracturing another bone.

"However, there is uncertainty as to whether this increased fracture risk is attributable to negative effects on bone mineral density, fall-related mechanisms (such as dizziness and low blood pressure when standing up), or associated (illnesses)," Lim wrote in his report.

The men taking diuretics in the study tended to be heavier, more sedentary, and more likely to suffer from other maladies including heart disease than non-users.

(Reporting by Andrew Stern; Editing by Maggie Fox and Eric Beech)