Medications can be tried first, often in an empirical way. An X-blocker (which blocks certain sympathetic nerve impulses). Yohimbine, seems to work in 30% of cases, regardless of etiology, and is usually worth a try (although critics claim placebo works by decreasing the inhibition of erections from anxiety via the sympathetics). Trazodone, a MAO inhibitor, has been reported to improve erections in 50%, primarily when the dysfunction is psychogenic. A new medication, --UK-92,480-- a phosphodiesterse inhibitor, is reported to be very effective, as it stops the breakdown of Nitrous Oxide in the penis, but will not be available in the US for another year.
Of course, if a low testosterone is found, and felt to be the cause of the problem, testosterone replacement is available, either as injections or a transdermal patch. Empirical use of testosterone for all types of erectile dysfunction is not recommended.
Injections of vasoactive medications directly into the corpora, using either Prostaglandin ("caverject"), or "trimix", a mixture of smaller amounts of prostaglandin, papervine and phentolamine, and which is more effective and less expensive that Caverject, can be done by patients, and is effective in all cases except those with excessive arterial or venous insufficiency.
Similarly, vacuum erection devices(which produce a vacuum to pool blood in the penis, and then keep it there with a compressive ring placed at the base of the penis), are widely effective, but are too cumbersome for use by many. Within the next few months an urethral suppository of prostaglandin, which is reported to produce erections in 40-60% of patients, will be available.
Direct vascular repair for arterial or arterial/venous mixed insufficiency can be done, with a 70% success rate, provided the rest of the vascular tree is not liable to suffer progressive vascular deterioration (usually in the presence of progressive vascular or coronary disease, severe diabetes, excessive smoking, or excessive age). Purely repairing venous leaks has not had a good long-term success rate (25-40% at one year, 10-30% at 3 years).
Finally, all types of erectile dysfunction can be reversed with implantation of a penile prosthesis. These are either semi-rigid or inflatable, self-contained or 2 to 3 piece. In the last 15 years they have become remarkably mechanically reliable, with revision rates less that 3%. Infection rates in non-diabetics are less than 5%, but in diabetics still 15-20%.