Today
The most widely used today, known as Tri-Mix, or Goldstein solution is the combination of PGE1, phentolamine and papaverine. This combination of vasodilating substances and relaxants of the cavernosal smooth muscle has enabled the use of very small doses from each drug, attaining success rates higher than 95% for male impotence cases of any etiology, with practically no side effects. Priapism reported lower than 0.5% of the cases and there is almost no corpora cavernosa fibrosis. In addition to that, this combination does not cause penile pain.

Treatment usually starts at a dose of papaverine 30 mg, phentolamine l mg, and alprostadil 20 µg. The usual dose of trimix solution ranges from 0.1 to 0.5 ml.

The goal
The goal is to achieve an erection that is adequate for sexual intercourse but does not last for more than one hour.

Penile Injection Technique

The actual technique of penile injections involves the use of a fine 29 or 30 gauge needle and 1-cc syringe, which is the same type of syringe that diabetics use for insulin, to inject as small a volume of fluid as possible. Generally the injections are made in the 10:00 and the 2:00 position in the sides of the penis.

The needle is placed in a perpendicular fashion to inject the entire contents of the syringe. It is not necessary to get a return of blood in the needle. Direct pressure should be applied over the injection site for several minutes. If the patient is on blood thinners such as Coumadin or aspirin, pressure is applied to the injection site for an additional period.

Penile injection therapy must always be initiated in the hospital or a well equipped clinic setting with careful instructions and close follow up of the patient. The technique appears deceptively simple, but it is not without numerous complications and side effects. Patients are at risk for scarring if the procedure is not performed correctly, and as a consequence of scarring, patients can also develop angulation and a variant of Peyronie's disease.

Most patients should be advised to use this technique only two to three times a week.