Their investigation follows reports that men bitten by the Uk can cialis female tadalafil take
nigriventer experienced priapism - long and painful erections.

A two-year study has found that the venom contains a toxin, called Tx2-6, that causes erections.

Further tests are being carried out in the US before the substance can be approved for human use.

The results, from the Medical College of Georgia, are expected in a month’s time.

The bite of Phoneutria nigriventer, known as the Brazilian wandering spider, is potent and can be deadly in some cases.

The Brazilian and US tadalafil 20mg toleranzentwicklung tadalafil
men who claimed their sex lives had improved after a spider attack.

The relevant toxin identified in the venom has been tested successfully on other animals.

So far, scientists believe that cialis tadalafil generic rezeptfrei
a version of the spider’s venom with an existing drug for erectile dysfunction - such as Viagra, Cialis or Levtra - could produce better results.

Human and animal trials suggest this could offer an alternative to current treatments for some patients, the American Society of Gene Therapy heard.

Researchers say gene therapy could be effective far longer than pills used just before sex, improving spontaneity.

The human trials involved injections into the penis and some experts queried whether men would choose this option.

New approach

Erectile dysfunction (ED), often referred to as impotence, is thought to affect about one in every 10 men in the UK.

ED collectively means an inability to get a good enough erection to achieve satisfactory intercourse, but it varies in severity.

There are many causes, and many effective treatments, including drugs like the three licensed in the UK - Viagra, Cialis and Levitra.

But not all types of ED respond well to medication - for example, ED caused by nerve damage following prostate cancer surgery.

US researchers are hopeful that for these patients, and those who experience side-effects with medication, gene therapy may be a good alternative.

Nerve damage

A University of Pittsburgh team, led by Dr Joseph Glorioso, tested an dosage tadalafil
gene therapy in rats with ED caused by nerve damage.

The gene therapy used comprised the herpes simplex virus as a carrier and either a gene called GDNF, or one called neurturin, which both help promote nerve growth.

Rats treated with the gene therapy showed significant recovery and were able to regain normal penile function after four weeks.

This is an exciting field of research because current treatments for men with erectile dysfunction must be used ‘on demand’, thereby reducing the spontaneity of the sexual act Researcher Dr Arnold Melman

Meanwhile, scientists at Wake Forest University, with the help of Dr Arnold Melman from the Albert Einstein College of Medicine, have been conducting the first human study of gene therapy for ED.

Tests on 11 men with ED showed promising results. The treatment was well-tolerated, with few side effects, despite its delivery via an injection into the penis.

Although the primary goal of the study was to determine its safety, it also showed the therapy improved erectile function in some of the men.

Dr Melman said: “This is an exciting field of research because current treatments for men with erectile dysfunction, whether pills or minimally invasive therapies, must be used ‘on demand’, thereby reducing the spontaneity of the sexual act.”

‘Chronic disease’

The Wake Forest therapy works by inserting small pieces of DNA into cells to trigger the production of proteins which, in turn, help smooth muscle cells relax.

Relaxing the smooth muscle in the penis allows it to fill with blood and achieve an erection.

Dr Geoff Hackett, president of the British Society for Sexual Medicine, said the gene therapy might be appealing to some men for whom other treatments had failed, but predicted many men would be reluctant to have a shot in the penis.

He stressed that many men with ED also had underlying medical disease, such as high blood pressure, raised tadalafil generika
or diabetes, and that this should also be treated.

And there is a good argument for treating ED as a chronic disease too, he said.

“Maybe men with ED should be taking a pill for it every day. If you take smaller amounts regularly, the side-effects are less,” he explained.

US researchers found an increased risk in men with a history of heart attack or high blood pressure.

The University of Alabama team said healthcare professionals should warn patients of the potential risk.

The British Journal of Ophthalmology study follows several reports linking the drugs to eyesight problems.

NAION A common cause of sudden vision loss in people over 50 Caused by a blockage of the tiny ciliary arteries supplying blood to the anterior optic nerve There is no direct treatment, although corticosteroids are sometimes used to reduce swelling in the optic nerve

The findings are based on 76 men attending one US specialist eye clinic.

Half the men had optic nerve damage, diagnosed as generic erectile dysfunction drug anterior ischaemic optic neuropathy (NAION), the rest were free of the problem.

All the patients were asked about their lifestyle, including smoking and alcohol intake, whether they had been diagnosed with heart disease, diabetes, or high blood pressure and prescribed treatment for these conditions.

They were also asked if they had been prescribed Viagra and Cialis for erectile difficulties.

Men with optic nerve damage were no more likely to have taken the impotency drugs than men in the comparison group.

But men who had had a heart attack were 10 times more likely to have optic nerve damage if they had taken Viagra or Cialis before their diagnosis.

Men with high blood pressure were also more likely to have optic nerve damage if they had taken these drugs, although this was not statistically significant.

Blood flow

The authors caution that their study is small, but suggest that the drugs may reduce the blood flow to the anterior optic nerve, resulting in tissue damage.

They believe the drugs may heighten the risk of NAION in those with vascular disease, who are already more erectile dysfunction drugs
.

The researchers urge any patient who has endured a sudden severe loss of vision, and has been prescribed Viagra or Cialis, to contact a doctor.

Writing in the journal, they said: “Though NAION is a rare condition, the large number of men using Viagra or Cialis suggests that, should an association truly exist, the incidence of NAION could rise tadalafil pills
.”

An editorial in the same journal points out that some patients with impaired eyesight as a result of NAION have reportedly decided to sue Pfizer, the manufacturers of Viagra.

However, Pfizer has said there were no reports of NAION in the trials of the drug carried out before it was licensed.

The company also argued that a greater number of cases related to this type of drug would have been reported by now if the association was anything other than coincidental.

Lilly ICOS, which manufactures Cialis, said there had been a small number of cases of NAION in people taking the drug.

This was now flagged up in the prescribing information.

In a statement, the company said it was difficult to establish a firm link as most patients taking impotency drug had other risk factors which rendered them potentially vulnerable to NAION.