Trials in European clinics have shown the treatment, known as MUSE, helped nearly 70% of men achieve intercourse.

Unlike the best-selling impotence pill Viagra, MUSE is used with an applicator.

Gordon Williams, a urologist at Hammersmith Hospital, London, who coordinated the trial of MUSE in 13 clinics across Europe found it helped 69% of the 159 men who received it achieve intercourse.

Long-term effects

He said: "Many other studies use a firm erection as a successful end-point. However, we used sexual intercourse as it is the best end-point to determine the efficacy of treatments for erectile dysfunction."

The study, published in the British Journal of Urology, showed that MUSE was effective both in the short and long term for men who suffered from impotence of a physical origin.

Viagra has become a best seller in America

Unlike the Viagra impotence pill which has enhanced the performance of thousands of American men, MUSE comes with an applicator that is inserted into the tip of the penis.

It releases a pellet with a specified dose of the drug alprostadil that causes an erection within five to 10 minutes and lasting for up to an hour.

A total of 763 doses of MUSE, made by US drug-maker VIVUS Inc, were administered during the trial and more than half resulted in sexual intercourse.

Nearly 250 patients were treated as outpatients and nearly two-thirds had intercourse. The successful patients were randomised to receive either MUSE or a placebo during a self-administered three-month trial at home.

Minor side effects

Nearly 70% of MUSE patients reported success, compared to 11% in the control group.

Side-effects with MUSE were local and minor and because it is a local treatment there is no danger of systemic side-effects, or reaction in other parts of the body.