Add-on tadalafil effective against LUTS/BPH resistant to silodosin
Use of tadalafil as an add-on therapy appears to be effective in patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia (LUTS/BPH) resistant to the α1-adrenoceptor blocker silodosin, a study has found.
The study included 103 LUTS/BPH patients with an International Prostate Symptom Score (IPSS) of >8 after ≥4 weeks of silodosin treatment. These patients were subsequently treated with either silodosin 4 mg twice daily (monotherapy group) or silodosin 4 mg twice daily plus tadalafil 5 mg once daily (add-on therapy group) for 8 weeks.
Outcomes of interest were the mean change from baseline to 8 weeks in the IPSS, Overactive Bladder Symptom Score (OABSS), maximum urine flow rate (Qmax) and post-void residual urine volume. Adverse events (AEs) were also evaluated.
Of the patients included, only 98.1 percent could continue medical treatment. Improvements in the IPSS, OABSS and Qmax were significantly greater 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; p<0.05 for all). AEs were reported in three patients in the add-on therapy group vs 1 in the monotherapy group, although the difference was not found to be significant (5.7 vs 2.0 percent; p=0.62).
In the subgroup of patients with overactive bladder (OAB; n=55), the add-on therapy group vs the monotherapy group demonstrated significantly greater improvements in the IPSS storage symptom subscore (−2.23 vs 0.17), IPSS urgency subscore (−0.88 vs 0.28) and OABSS urgency subscore (1.5 vs −0.48; p<0.05 for all).
Men with LUTS/BPH commonly show symptoms of a mixed nature, such as bladder storage (eg, daytime urinary frequency, nocturia, urgency or urinary incontinence), voiding (eg, slow stream, splitting or spraying, intermittency, hesitancy, straining and terminal dribble) and/or postmicturition symptoms (sensation of incomplete emptying or post-micturition dribble). Storage symptoms have been shown to have a greater negative effect on quality of life (QoL) than voiding symptoms do and exhibit stronger correlations with QoL across all treatment modalities. [Eur Urol 2013;64:118–140; Int J Clin Pract 2012;66:883–90; World J Urol 2010;28:3–8]
Currently, α-blockers (eg, alfuzosin, doxazosin, silodosin, tamsulosin and terazosin) are used as first-line treatment for managing the signs or symptoms of LUTS/BPH. The 5α-reductase inhibitors (eg, dutasteride and finasteride) are used to manage benign prostatic enlargement, while antimuscarinic agents (eg, oxybutynin, propiverine, solifenacin and tolteroidine) are primarily prescribed to treat OAB and other storage symptoms. On the other hand, the phosphodiesterase-5 inhibitors (eg, tadalafil) are used to treat the signs or symptoms or BPH with or without erectile dysfunction. [Rev Mex Urol 2016;76:360–369; Eur Urol 2015;67:114–122]