An update on pharmacological treatment of erectile dysfunction with phosphodiesterase type 5 inhibitors

INTRODUCTION

Phosphodiesterase type 5 inhibitors (PDE5-i) are used for the oral treatment of erectile dysfunction (ED). Since the launch of sildenafil more than 15 years ago, new molecules have become available. At present, in addition to tadalafil and vardenafil, there are three other drugs, udenafil, avanafil and mirodenafil, marketed in some countries which appear to be promising.

AREAS COVERED

The clinical pharmacological differences in dosage and side effects of all PDE5-i are evaluated.

EXPERT OPINION

All PDE5-i are equally effective and safe for the treatment of ED. On-demand use of any PDE5-i is also safe for patients with comorbid conditions. Tadalafil seems to be the preferred drug by patients and physicians, probably due to its peculiar pharmacological profile that makes sexual intercourse more spontaneous for the patients. Preliminary data suggest that the use of vardenafil may also be beneficial in cases of ED associated with premature ejaculation. Daily treatment is another option in men with ED and documented vascular or prostate disease. In geriatric or in difficult-to-treat populations, the evaluation of testosterone plasma levels will help to predict the efficacy of any PDE5-i. Remarkably, when such drugs are withdrawn for any reason, ED most often continues to occur because of the presence of an underlying disease.

Efficacy and Safety of Tadalafil 5 mg Administered Once Daily in Korean Men with Erectile Dysfunction: A Prospective, Multicenter Study

PURPOSE

The aim of this study was to evaluate the efficacy of a daily dose of tadalafil 5 mg as well as its safety for the cardiovascular system in men with erectile dysfunction.

MATERIALS AND METHODS

This study included a total of 162 men who were administered a daily dose of tadalafil 5 mg between April and December of 2009. A total of 127 men completed the 8-week clinical trial. The International Index of Erectile Function (IIEF)-5, blood pressure, and heart rate were measured before treatment with tadalafil (V1) and 4 (V2) and 8 weeks (V3) after treatment with tadalafil. Adverse effects were assessed at V1, V2, and V3. In cases in which the International Prostate Symptom Score (IPSS) was ≥8 at V1, maximal flow rate (Qmax) and postvoid residual volume (PVR) were measured.

RESULTS

The IIEF-5 values were 11.25±3.18, 14.56±3.79, and 16.91±3.56 at V1, V2, and V3, respectively, with significant improvement (V1 vs. V2, p<0.001; V1 vs. V3, p<0.001). The IPSS values were 10.59±5.56, 9.07±6.06, and 8.15±6.10 at V1, V2, and V3, respectively, and the differences were statistically significant (V1 vs. V2, p<0.001; V1 vs. V3, p<0.001). There were no significant differences in blood pressure or heart rate. Adverse effects were observed in 7 men (5.51%) at V2 and in 5 men (3.94%) at V3.

CONCLUSIONS

Tadalafil 5 mg administered once-a-day may be effective in improving erectile function. Adverse effects on the cardiovascular system may be minimal. In addition, it is believed that this may also be effective in improving voiding symptoms.