The usual starting dose of prostaglandin E 1 is 2.5-5 micrograms. Generally, men with vasculogenic impotence require higher doses than those with neurogenic or psychogenic impotence. The starting doses should be adjusted accordingly. In practical terms, this is defined as an erection firm enough for penetration and lasting from 20-60 minutes. Intracavernosal therapy should generally be supervised by a doctor with appropriate experience.
Regular monitoring is essential.
If an inadequate response is achieved with maximal prostaglandin E 1 dosage, combination therapy with papaverine alone or with phentolamine has been reported to improve the response. Reliable clinical trials of such add-on therapy are lacking. In addition, the chemical compatibility, stability and sterility of these ad hoc mixtures is not assured. The most frequent adverse effect of prostaglandin E 1 intracavernosal therapy is penile or perineal pain. Other minor adverse effects include haematoma, oedema or scarring.