Drug combo can be deadly

Spironolactone, a diuretic used to treat heart failure, can cause a risk of sudden death in seniors when given with the antibiotic trimethoprim-sulfamethoxazole, Toronto researchers have found.

The drugs can cause blood potassium levels to spike and cause irregular heart rhythms. Trimethoprim-sulfamethoxazole is often given to treat urinary tract infections. Spironolactone blocks a hormone that causes salt and fluid buildup in the heart. 

The study ran for 17 years with 206,319 patients. The findings appeared Feb. 2 in the Canadian Medical Association Journal.