ED Drug Shows Promise in Sheep Heart Failure Study

Illustration of heart in body

A medication best known as a treatment for erectile dysfunction could have benefits in preventing heart failure.

Research published in the journal Scientific Reports shows that tadalafil, the active medication in Eli Lillys Cialis and Pfizers Viagra, slowed the progression of heart failure in a study involving sheep. Tadalafil blocks phosphodiesterase 5 (PDE5) with high specificity. PDE5 regulates how the body’s tissue responds to hormones such as adrenaline. Researchers from the University of Manchester used a sheep model of advanced heart failure to show that tadalafil treatment improves contractile function, reverses transverse tubule loss, restores calcium transient amplitude and the heart’s response to catecholamines, the researchers said in the abstract. PDE5s were originally developed as a cardiac medication.

Heart failure is typically characterized by the heart’s inability to pump enough blood to meet the body's needs. The disease has a low survival rate and typically causes a build-up of fluids, which back up into the lungs. This results in a painful breathlessness, as well as fluid retention that causes various parts of the body to swell up.

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While few treatments are effective against heart failure, the animal study does show that tadalafil has promise in this area. The study’s lead author, Professor Andrew Trafford, believes the effects seen in the sheep are also likely to be seen in humans due to the fact that the physiology of sheep hearts is similar to human hearts. He said there is limited evidence from human trials and epidemiological studies that show Tadalafil can be effective in treating heart failure.

“This discovery is an important advance in a devastating condition which causes misery for thousands of people across the UK and beyond,” Trafford said in a statement. “This study provides further confirmation, adds mechanistic details and demonstrates that tadalafil could now be a possible therapy for heart failure.”

During the course of the study, heart failure in the sheep was induced by pacemakers. The heart failure in the animals was considered sufficiently advanced enough to need treatment and the medication was administered. Within a short period of time, tadalafil stopped the progressive worsening of the heart failure, the University of Manchester noted in its release. Most importantly, the researchers noted that the drug reversed the effects of heart failure, including the breathlessness associated with heart failure. The researchers said this was almost completely reversed. The dose that was provided to the sheep was similar to the dosage given to humans who are prescribed tadalafil for erectile dysfunction.

“This is a widely used and very safe drug with minimal side effects. However, we would not advise the public to treat themselves with the drug and should always speaking to their doctor if they have any concerns or questions,” Trafford said. “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.”

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