Efficacy of Tadalafil Therapy and Changes in Oxidative Stress Levels in Male Patients with Lower Urinary Tract Symptoms and Overactive Bladder

OBJECTIVE: To evaluate the effects of tadalafil monotherapy on lower urinary tract symptoms, urodynamic parameters, and oxidative stress levels in male patients. METHODS: This prospective study included 53 male patients with urinary symptoms, who met the criteria for overactive bladder (OAB) (≥ 2 points for Q3 [urgency] in the OAB symptom score [OABSS] assessment and ≥ 3 points for the total score). The patients received 5 mg tadalafil orally once daily, and their symptoms were assessed before and after the 12‐week treatment. The OABSS and international prostate symptom score (IPSS) were used to evaluate the subjective symptoms. The objective findings were assessed using uroflowmetry. Oxidative stress was assessed by determining urinary levels of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) levels with an adjustment for urinary creatinine (CR) concentration. RESULTS: After tadalafil administration, total and individual indices of the OABSS assessment showed significant improvement. In addition, total storage and voiding symptoms that contributed to the IPSS were also significantly improved. The voided volume was increased, and the maximum flow rate was improved after tadalafil treatment (P = .002 and < 0.001, respectively). Urinary 8‐OHdG/CR decreased from 12.4 ± 9.7 ng/mg CR to 7.6 ± 11.6 ng/mg CR (P < .001). In patients who showed OAB improvement and did not meet the criteria for OAB after the treatment (44 patients, 83.0%), the urinary 8‐OHdG/CR level was significantly decreased from 11.6 ± 8.4 ng/mg CR to 6.4 ± 10.3 ng/mg CR (P < .001). CONCLUSIONS: Tadalafil treatment improves OAB symptoms and urodynamic parameters by decreasing oxidative stress level.