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 respond less to standard treatments for the condition.
Erectile dysfunction (ED), the inability to achieve and maintain an erection, affects half of men between the ages of 40 and 70 to some degree.
Causes include a narrowing of the blood vessels that supply the penis, which may be associated with heart disease and high cholesterol.
Men with diabetes are more at risk for erectile dysfunction because their bodies cannot control blood sugar levels effectively; High blood sugar levels can damage the blood vessels and nerves that help produce an erection.
Viagra-type medications (known as PDE5 inhibitors) treat erectile dysfunction by increasing levels of nitric oxide, which widens blood vessels to allow better blood flow. The effects last up to four hours.
Erectile dysfunction affects half of men between 40 and 70 years of age to some degree.
But although they help in about 70 percent of cases, they are not suitable for men taking nitrates (an angina medication), for example, nor for those who have liver problems or who have recently had a stroke.
Men in the new trial include those with severe erectile dysfunction or those for whom Viagra-type medications have not worked.
Botulinum toxin (the active compound found in Botox injections) blocks nerve signals that cause muscles to contract.
Previous research has suggested that it may help with erectile dysfunction as it relaxes the muscles around the blood vessels that supply the penis, helping to improve blood flow.
It also prevents the release of norepinephrine, a chemical messenger that reduces blood flow.
The 32 men 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 trial of 216 men, most of whom had not responded to Viagra-like medications. At the beginning of this trial, the men had received two Botox injections, one into each of the two spongy chambers that run through the penis and fill with blood to create an erection (numbing creams or gels were applied first).
After the first injection there was a significant improvement in 85 percent of men with mild ED, 79 percent of those with moderate ED, and 64 percent of those with severe ED.
Over the next six years, more injections were made on demand; the response rate increased as they were repeated (it is not clear why).
Among those with mild and moderate ED, there was a 50 percent overall improvement at the end of the trial, while there was a nearly threefold improvement in those with severe disease, researchers from Poincaré University Hospital in France reported in an article in Toxins magazine.
Results from the new trial, which is being carried out at Aswan University in Egypt, are expected next year.
Commenting on the study, Professor Raj Persad, consultant urologist at Bristol Urology Associates, said: “The use of Botox appears attractive as, although it involves an injection into the penis on each side, it avoids the discomfort of using vacuum erection devices, that by themselves may not work, or pharmacological agents that must be injected before each sexual encounter.
“If the trial results are verified in daily clinical practice, this approach could add greater flexibility to the treatment of erectile dysfunction.”
Men whose diets are rich in vitamin B6 (found in foods such as fish, chickpeas, and fortified cereals) are less likely to suffer from 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 believed to reduce levels of homocysteine, an amino acid that can damage arteries and reduce blood flow.
