A new study shows heart failure may be slowed or possibly reversed when treated with a drug commonly used to treat erectile dysfunction in men.
British Scientists at the University of Manchester found that tadalafil, which is sold under the brand name Cialis, was an effective treatment for heart failure in sheep, according to the study published on Wednesday in Scientific Reports.
"This discovery is an important advance in a devastating condition which causes misery for thousands of people across the UK and beyond," professor Andrew Trafford, one of the study's authors told Medical Xpress.
Although the research in humans is limited, Trafford believes the findings showed promise for patients suffering from the debilitating condition.
"We do have limited evidence from human trials and epidemiological studies that show Tadalafil can be effective in treating heart failure," he said. "This study provides further confirmation, adds mechanistic details and demonstrates that Tadalafil could now be a possible therapy for heart failure.
What is heart failure?
Heart failure is a chronic, progressive condition that occurs when the heart is unable to pump enough blood to meet the body's needs for blood and oxygen, according to the American Heart Association.
Symptoms may include shortness of breath, persistent coughing or wheezing, fluid retention, fatigue, confusion, and increased heart rate. The five-year survival rate is lower than many common cancers.
How does the medication work?
The researchers induced heart failure in the animals using pacemakers. The physiology of sheep hearts is similar to human hearts, according to the authors.
Once the animals' hearts showed progressive signs of heart failure, the scientists started administering tadalafil. The dosage was similar to the amount used to treat erectile dysfunction in men.
Over a short period, the sheep's heart failure stopped, but most importantly, the effects of the condition were reversed.
Tadalafil blocks an enzyme called Phosphodiesterase 5 or PDE5S for short, which prevents tissues from responding correctly to catecholamines including epinephrine, also known as adrenaline.
The drug stopped the reaction to PDE5S and restored the heart's ability to respond to adrenaline and force blood throughout the body.
Trafford told Medical Xpress that erectile dysfunction patients who have used the medication might have inadvertently received protective benefits.
"It's entirely possible that some patients taking it for erectile dysfunction have also unwittingly enjoyed a protective effect on their heart," Trafford said.
But he doesn't recommend attempting to treat heart failure without the advice of a doctor.
"Tadalafil is only suitable as a treatment for systolic heart failure — when the heart is not able to pump properly — and there may be interactions with other drugs patients are taking," Trafford added.
The British Heart Foundation funded the study.