Comparison of Silodosin Monotherapy vs Silodosin With Tadalafil Add-on Therapy in Patients With Benign Prostatic Hyperplasia.

Objective: To evaluate the efficacy and safety of add-on therapy with the phosphodiesterase type 5 inhibitor tadalafil for patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia (LUTS/BPH) treated with the α-adrenoceptor blocker silodosin.

Materials And Methods: We analyzed 103 patients with LUTS/BPH with an International Prostate Symptom Score (IPSS) of >8 after ≥4 weeks of silodosin treatment from April 2016 through December 2016 at Kori Hospital. The patients subsequently received silodosin 4.0 mg twice daily (monotherapy group) or silodosin 4.0 mg twice daily plus tadalafil 5.0 mg once daily (add-on therapy group) for 8 weeks. We assessed adverse events and evaluated the mean change from baseline to 8 weeks in the IPSS, Overactive Bladder Symptom Score (OABSS), maximum urine flow rate (Q), and post-void residual urine volume.

Results: Of 103 patients, 101 (98.1%) could continue medical treatment. The IPSS, OABSS, and Q showed significantly greater improvement in the add-on therapy than in the monotherapy group (-3.92 vs -1.24, -1.18 vs 0.10, and 1.09 vs -1.04, respectively; all P <.05). Although 4 patients experienced adverse events (add-on therapy: n = 3, 5.7%; monotherapy: n = 1, 2.0%), no significant differences were observed (P = .62). Among patients with overactive bladder (n = 55), the IPSS storage symptom subscore, IPSS urgency subscore, and OABSS urgency subscore showed significantly greater improvement in the add-on therapy than in the monotherapy group (-2.23 vs 0.17, -0.88 vs 0.28, and -1.5 vs -0.48, respectively; all P <.05).

Conclusion: Add-on therapy with tadalafil may be effective for patients with LUTS/BPH resistant to silodosin monotherapy.