In the study, funded by Viagra's maker Pfizer, 568 men on more than one medication to control their blood pressure tried Viagra for 6 to 12 weeks.
Most reported improvements in their erections and ability to have intercourse, and none reported any warning signs of serious side effects for the heart.
These findings suggest that for the many men coping with both high blood pressure and erectile dysfunction, Viagra may help, study author Dr. Thomas G. Pickering of Columbia University in New York told Reuters Health.
More than one-quarter of American men 18 and older have high blood pressure, or hypertension, and the rate of the condition increases with age -- topping more than 70 percent in those 75 and older.
Some studies have shown that up to 70 percent of men with hypertension also have erectile dysfunction, perhaps stemming from the disease or the blood pressure lowering drugs used to treat it.
In the American Journal of Hypertension, Pickering and his team write that men who suffer from erectile problems are "at increased risk" of choosing to stop their blood pressure medications.
However, in an interview, Pickering explained that experts have been concerned that men who take Viagra and blood pressure medications might experience a precipitous drop in blood pressure.
This concern stemmed from observations that men who take a class of drug called nitrates for angina can experience a dangerous plunge in blood pressure after taking Viagra, he noted.