A Prospective Randomized Comparative Study to Evaluate the Effect of Once Daily Dose of Tadalafil (5 mg) vs. On-Demand Tadalafil (10 mg) on International Index for Erectile Function (IIEF) Score

BACKGROUND Erectile dysfunction is a common condition affecting middle and old age men throughout the world. Tadalafil is preferred by many urologists as well as patients because of its long half-life. Tadalafil on demand was compared with daily dosing in many studies. We wanted to conduct the study in south India at a tertiary care medical center to study the effect of tadalafil daily (5 mg) vs. on demand (10 mg) and check its efficacy with the IIEF scoring system. METHODS Patients were randomised into two groups using simple randomization chit box method. Allocation concealments was done by sealed enveloped method. Before starting treatment IIEF scoring was done for both groups. Group A was given once-daily 5 mg tadalafil. The group B was given 10 mg tadalafil before sexual activity. All patients under either of the two medication regimens for a period of 12 wks. and assessment done at 4 wks. and 12 wks. interval. Both the patient and the examiner was blinded to the randomisation of the subjects. Scoring scale is 1 to 30 which is divided into five groups of sever, moderate, mild to moderate, mild, and no dysfunction for score of 0 - 10, 11 - 16, 17 - 21, 22 - 25, and 26 - 30 respectively. RESULTS Tadalafil 5 mg OD has statistically significant better result when compared with IIEF score after 4 wks. with percentage improvement of 21.12 % when compared to baseline, with a P value of < 0.0001. In group II tadalafil 10 mg on demand shows statistically significant results when IIEF score baseline was compared with that after 4 wks. When group I compared with group II for mean difference of score after 4 wks. group I shows statistically significant improvement with P value 0.017 (< 0.05). When compared with score after 16 wks. with baseline both group I and II shows statistically significant improvement in IIEF score. But group I which shows mean difference in score of 5.40 (42.05 % improvement from baseline) is a statistically significant difference (p value - 0.0001) when compared to group II which shows mean difference of score at 16 wks. as 2.73 (20.71 % improvement from baseline). CONCLUSIONS Tadalafil 5 mg daily provides significant increase in IIEF score as compared to on demand 10 mg tadalafil. We need longer duration of study the side effects in each group. KEYWORDS Tadalafil, IIEF, Once a Day, On Demand, Erectile Dysfunction