- Doctors say Mirabegron could provide an alternative for one in three men
- Drug works by relaxing muscles in the penis, allowing more blood to flow to it
- Erectile dysfunction is a common problem, often effecting men in middle age
- Can occur as result of vascular issues, such as high blood pressure and diabetes
A once-a-day tablet taken by sufferers of incontinence may be a new way to treat flagging libido in men.
Doctors say the drug Mirabegron could provide an alternative for up to one in three men who fail to respond to Viagra-type medications.
A pilot study from Johns Hopkins University in America has shown it is effective, following the serendipitous discovery that people prescribed Mirabegron did not suffer the common side effect of taking beta-blockers – erectile dysfunction (ED).
Defined as the inability to develop and maintain an erection for satisfactory sexual intercourse, ED is a common problem, with studies suggesting that one in five men over 40 have at least a ‘moderate’ dysfunction.
The incidence increases with age and it can occur as a result of vascular issues, such as high blood pressure, diabetes and atherosclerosis or furring up of the arteries, which affect blood flow.
It can also happen after prostate surgery.
The use of Viagra (active ingredient sildenafil) is increasing rapidly, according to statistics released by the Health and Social Care Information Centre.
There were 1.7 million prescriptions for the drug in 2015, up by 15 per cent year on year.
Viagra, along with Cialis (tadalafil), Levitra (vardenafil) and Spedra (avanafil), is in a class of drugs known as PDE5 inhibitors, and can be highly effective for some men.
These drugs work by altering the cascade of chemical events in the body that occurs with sexual excitement.
But according to a study by urologists at Columbia University, 30 to 35 per cent of men who need help with sexual function fail to respond to these drugs.
And men who have serious heart problems, high or low blood pressure, severe liver or kidney disease, or some eye problems should not use them.
There are side effects too, including headaches and stomach problems.
Mirabegron is a new type of drug that has recently been approved for the treatment of overactive bladder, a form of incontinence that affects about five million Britons.
It works by relaxing the bladder muscles to reduce the urge to urinate. It does so by stimulating beta-3 adrenergic receptors which are found in bladder tissue and signal muscles to relax.
These receptors are also found at high levels in penile tissue.
When the receptors respond, they relax the penis’s smooth muscle, encouraging blood to flow and an erection to be maintained.
Research reported in the British Journal Of Urology International shows that Mirabegron can be highly effective.
Researchers from Tulane University and other centres in the US carried out a series of tests on both human tissue and animals.
Results show that it ‘markedly relaxed’ muscles, and that the greater the dose, the better the effect.
Mirabegron is a new type of drug that has recently been approved for the treatment of overactive bladder and could now help sufferers of erectile dysfunction (file photo)
‘The major finding of the present study shows that it relaxed smooth muscle and in a concentration-linked manner,’ say the researchers.
Now a human trial is under way at Johns Hopkins University involving men with mild to moderate ED, aged between 18 and 70, who will be given the drug daily for 12 weeks.
Professor Mike Wyllie, chief scientific officer of Plethora Solutions, and a member of the team that developed Viagra, said: ‘The research is an important step in trying to find a way to help men who do not respond to PDE inhibitors like Viagra, by looking for alternative erection-producing mechanisms.
‘It has become obvious that for every patient satisfied with PDE inhibitors, there is one who gets an inadequate erection. So we really do need a treatment for this group of patients.’
Despite its potential, Mirabegron – known as Betmiga when prescribed for incontinence – is not without its downsides.
Side effects include increased blood pressure, the inability to fully empty the bladder (known as urinary retention), sinus pain, dry mouth, digestive complaints and dizziness.