The primary complaint includes penile pain. The side effects associated with intraurethral administration of alprostadil are similar to those associated with intracavernous injection. In this report, 50 percent achieved successful intercourse in the home setting. In the largest study on this route of introduction of alprostadil,approximately two-thirds of the patients tested in the office setting had a subsequent erection adequate for intercourse. The doses delivered by the intraurethral administrations, however, are significantly larger (usually 500 to 1000 micrograms) than the dose delivered by intracavernous injection. The dose is introduced through a small, plastic applicator placed inside the opening of the urethra. In early 1997 the intraurethral administration of alprostadil became available for clinical use after being approved by the FDA. With the availability of Viagra as the now accepted first line of therapy, the second line of therapy includes less invasive procedures involving intraurethral suppositories and vacuum erection devices, which will be discussed in the upcoming chapters. Even with the side effects of penile fibrosis, sustained erection (priapism), and penile pain, the benefits of this injection technique, with any of the above agents for the last 15 years has been tremendous.

While injection therapy is not first line therapy, now with the availability of Viagra as an oral agent, injection therapy has moved from second line to third line therapy. No cases of penile fibrosis or priapism have been reported with the MUSE. In my own experience, less than 30 percent of patients had a satisfactory erection. The vast majority of patients say the gain is not worth the pain. Most were individuals who would have received intracavernous injection therapy with papaverine as the next step in their evaluation and treatment. In early 1997, patients across the country were treated with the intraurethral suppository (MUSE). However, about 4 percent of the patients did have hypotension (low blood pressure). Less often reported are side effects from systemic absorption.