Comparative Efficacy of Tadalafil and Amitriptyline in Female Interstitial Cystitis/Bladder Pain Syndrome: Double-Blind Randomized Trial.

INTRODUCTION AND HYPOTHESIS: Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic debilitating disorder of unclear etiology that impairs quality of life; physically, emotionally, and sexually. Up till now, no standard effective therapy has existed. Phosphodiesterase-5 inhibitors are vasodilatory and anti-inflammatory. We studied the efficacy and safety of tadalafil, amitriptyline, and their combination in female IC/BPS patients.

METHODS

In this study, 132 female patients were randomized into three groups. Assessments were performed at baseline and at 4, 8, and 12 weeks using voiding diary, uroflowmetry, the visual analog scale (VAS), the Interstitial Cystitis Symptom Index (ICSI), and the Interstitial Cystitis Problem Index (ICPI). Global Response Assessment (GRA) and correlations between VAS and voided volume were analyzed at the end. Statistical analysis was performed using the Kruskal-Wallis test.

RESULTS

Tadalafil and combination improved daytime voids more than amitriptyline (tadalafil vs amitriptyline p = 0.0005, amitriptyline vs combination p < 0.0001, tadalafil vs combination p = 0.0009). Night-time voids improved notably in tadalafil and combination vs amitriptyline (p < 0.0001). Maximum urinary flow rate (Qmax) increased in combination and tadalafil vs amitriptyline (p = 0.0004) and (p = 0.0294) respectively. Voided volume was higher in combination vs amitriptyline (p = 0.0041). ICSI, ICPI, and VAS scores decreased in all groups (p < 0.0001). Ninety-two patients achieved a GRA score of 7. VAS correlated with voided volume in the tadalafil group (r = -0.60). Amenorrhea was the most bothering adverse event among the patients in the tadalafil group.

CONCLUSIONS

Tadalafil, alone or combined with low-dose amitriptyline, is a safe and effective treatment for female IC/BPS. The combination had comparable or superior efficacy to tadalafil using a lower amitriptyline dose while reducing adverse events.