Tamoxifen dilates arteries in men

The breast cancer drug tamoxifen can widen a narrowed coronary artery in men with heart problems, a new study shows. Although the test population comprised only a few dozen participants, the study suggests that the drug may play a valuable role beyond fighting cancer.

Researchers gave tamoxifen orally for 56 days to 16 men–average age 61–with heart disease. Fifteen other men in similar health–average age 64–received an inactive pill. All these volunteers were taking aspirin and cholesterol-lowering drugs called statins. Ten other men without severe heart disease but with chest pain called angina received only tamoxifen.

Using ultrasound, physicians then measured artery dilation, the percentage by which a coronary artery expands with each beat of the heart. In the heart patients getting tamoxifen, average dilation improved from 2.1 percent per beat at the start of the study to 7.5 percent at the end, the researchers report in the March 20 Circulation. In the patients getting the placebo, dilation remained unchanged at 2.1 percent. Dilation in the men with angina who took tamoxifen rose during the study from 3.8 percent to 7.9 percent per beat.

Increased dilation facilitates blood flow and eases the risk of heart attack. Men have an average coronary artery dilation of 7 percent until age 40. This drops to about 5 percent by age 51 and to 3.5 percent around age 63, says study coauthor James C. Metcalfe of the University of Cambridge in England. The figures are lower for men with heart disease.

The men getting tamoxifen also saw significant reductions in blood concentrations of fibrinogen, a blood-clotting compound.