Prediction of Sildenafil Response according to Intracavernosal Injection Test in Patients with Erectile Dysfunction

Lee, Jeong Seon; Jung, Seung Il; Park, Kwangsung

Abstract

PURPOSE
The aim of our study was to assess whether an intracavernous injection test can predict the effectiveness of sildenafil oral medication in patients with erectile dysfunction (ED).
MATERIALS AND METHODS
A total of 80 patients with ED underwent an intracavernous injection test with trimix (papaverine 18.75 mg+phentolamine 0.625 mg+PGE1 6.25microgram/ml) 0.2 ml. Patients were divided into 2 groups according to rigidity formation following trimix injection: group I had no rigidity formation, group II had some rigidity formation. All patients received a starting dose of 50 mg sildenafil. The dose was adjusted to 100 mg based on its efficacy and tolerability. Erectile function was measured before and during the therapy using the International Index of Erectile Function (IIEF) questionnaire.
RESULTS
All patients had erection function (EF) domain scores of the IIEF less than 16, denoting moderate to severe ED (group I, 50 patients; group II, 30 patients). The response rates with sildenafil 50 mg were 24% (12/50) in group I and 87% (26/30) in group II. The overall response rates with sildenafil (50 mg or 100 mg) were 68% (34/50) in group I and 93% (28/30) in group II. The change in ED domain score was significantly higher in group II (9.87+/-3.18 to 15.40+/-4.50; p<0.001) compared to group I (7.80+/-2.43 to 9.08+/-3.84).
CONCLUSIONS
The erectile response from the intracavernosal injection test was correlated with the sildenafil response rate. This result implies that intracavernosal injection test may predict the erectile response to oral phosphodiesterase type 5 inhibitor.