Currently, several medications are used for this purpose. Papaverine was the first one used. Phentolamine, an alpha blocker, was used second, initially as an additive to papaverine, and later to prostaglandin El. Alprostdil is also used under the name Caverject. Papaverine and prostaglandin both act on smooth muscle tissue in the corpora cavernosa, while phentolamine is more effective in the tiny penile arteries to prolong the erection.
Most doctors mix all three drugs together.
The patient must learn to inject the base of the penis using less than 1 cc. Either corpus cavernosum may be injected but not the urethra. Hand pressure is applied afterward for 2-3 minutes to prevent bleeding. Ideally, erections will last 30-60 minutes and will become more rigid if stimulation occurs. With injection treatment, high quality erections are available on demand, and they last longer than natural ones.