Introduction and Objective:

Intracavernous injection of Trimix (Tx) is indicated for patients unsuitable for prostaglandin E1 (PgE1) injection due to lack of response, pain or cost. We believe that the ideal ratio of ingredient doses in Tx is yet to be found. We postulated that increasing the doses of individual drug components in an orderly manner would convey important data on penile hemodynamic response. Such information is needed to choose an effective and less costly alternative to PgE1 with least side effects. We set out to evaluate the impact of varying the ingredient dosage on response and short-term safety of Tx compared with PgE1. We prospectively randomized 180 consecutive patients with erectile dysfunction into nine equal groups and each group received a different dose of Tx, namely phentolamine (1 mg) plus one dose of PgE1 (2.5, 5 or 10 μg) and one dose of papaverine (5, 10 or 20 mg). Each patient was injected with 20 μg PgE1 and one dose of Tx in two clinic visits 1 week apart. Following injection, duplex ultrasound of cavernous arteries and axial rigidometry were carried out. Patients ranked the quality of erection, estimated overall satisfaction and reported time to detumescence and side effects. Patients’ mean age was 50.5±11.7 y with underlying organic condition in 91.1%. We set out to evaluate, by means of an acute, prospective, randomized, single blind study, the various dose combinations of Tx versus PgE1 20 μg using both subjective and objective end points.

Hypothesis:

We think that the ideal ratio of ingredient doses in Tx is yet to be found. The effect of increasing individual drug components on penile response is not known. Such information is needed to choose an effective and less costly alternative to PgE1 with least side effects.

Results:

In spite of oral drug therapy for ED, there is a considerable number of candidates for self-injection therapy. These include patients who do not respond to or have a contraindication for PDE-5 inhibitor treatment. In addition, some patients prefer the rigidity provided by injections. In patients undergoing ICI therapy and given the option to try sildenafil, 36.2% decided to use injections most of the time or at least sporadically. The association of multiple vasoactive drugs produces a full erectile response in more than 90% of patients. In nonresponders to doses as high as 40 μg PGE1, Tx combination produced a response in 31%. The cost of the medication is another important issue where Tx has an advantage.