A trial is underway to investigate whether a single injection of Botox can improve symptoms of erectile dysfunction in men with diabetes – who tend to be less responsive to standard treatments for the condition.
Erectile dysfunction (ED), the inability to get and maintain an erection, affects half of men between the ages of 40 and 70 to some extent.
The causes include narrowing of the blood vessels that supply the penis, which can be linked to heart disease and high cholesterol.
Men with diabetes are at greater risk of erectile dysfunction because their bodies cannot effectively control blood sugar levels. Elevated blood sugar levels can damage the blood vessels and nerves that help cause an erection.
Viagra-type drugs (known as PDE5 inhibitors) treat erectile dysfunction by increasing levels of nitric oxide, which dilates blood vessels and allows better blood flow. The effects last up to four hours.
Erectile dysfunction affects half of men between the ages of 40 and 70 to some extent
But although they help in about 70 percent of cases, they are not suitable for men who are taking nitrates (anti-angina medication), for example, or for people who have liver problems or have recently had a stroke.
The men participating in the new study include people with severe erectile dysfunction or those for whom Viagra-type medications have not worked.
Botulinum toxin (the active ingredient found in Botox shots) blocks signals from nerves that cause muscles to contract.
Previous research has suggested that it may help with erectile dysfunction because it relaxes the muscles around the blood vessels that supply the penis, improving blood flow.
It also prevents the release of norepinephrine, a chemical messenger that reduces blood flow.
The 32 men taking part in the new trial will receive a single injection of botulinum toxin and then take a pill containing 5 mg of tadalafil, a PDE5 inhibitor, daily for three months.
This follows a recent study of 216 men, most of whom did not respond to Viagra-like medications. At the start of this trial, the men had received two Botox injections, one into each of the two spongy chambers that run along the length of the penis and fill with blood to create an erection (numbing creams or gels applied).
After the first injection, there was a meaningful improvement in 85 percent of men with mild erectile dysfunction, 79 percent of those with moderate erectile dysfunction and 64 percent of those with severe erectile dysfunction.
Over the next six years, further injections were performed on request – the response rate increased as it was repeated (it is unclear why).
Among those with mild to moderate erectile dysfunction, there was a 50 percent overall improvement by the end of the study, while there was a nearly threefold improvement among those with severe disease, the researchers from Poincare University Hospital in France, wrote in the magazine Toxins.
Results from the new trial, underway at Aswan University in Egypt, are expected next year.
Commenting on the research, Professor Raj Persad, a consultant urologist at Bristol Urology Associates, said: ‘The use of Botox would seem attractive because, although it involves an injection into the penis on each side, it avoids the cumbersomeness of using vacuum erection devices, which themselves may not work, or pharmacological agents that must be injected before each sexual encounter.
‘If the study results are verified in daily clinical practice, this approach could add more flexibility to the treatment of erectile dysfunction.’
Men whose diets are rich in vitamin B6 – found in foods such as fish, chickpeas and fortified grains – are less likely to develop erectile dysfunction (ED), reports the journal Translational Andrology and Urology.
Analysis of data from 3,875 men found that those who consumed the highest levels of the vitamin had a 23 percent lower risk of erectile dysfunction (other B vitamins also reduced the risk). B vitamins are thought to lower levels of homocysteine, an amino acid that can damage blood vessels and reduce blood flow.