Effect of Tadalafil on prostate haemodynamics: preliminary evaluation with contrast-enhanced US

Purpose. Phosphodiesterase-5 (PDE-5) inhibitors have an established role in the treatment of erectile dysfunction, but there is increasing evidence that these drugs are effective also for the treatment of lower urinary tract symptoms and benign prostatic hyperplasia (BPH). The mechanism of action of PDE-5 inhibitors in the prostate, however, is poorly understood. It is conceivable that these drugs act by reducing the smooth muscle tone of the organ, but this effect could produce vascular changes as well. The aim of this study was to investigate whether administration of Tadalafil, a PDE-5 inhibitor, in patients with BPH produces haemodynamic changes in the prostate that can be assessed using contrast-enhanced US (CEUS). Materials and methods. Twelve consecutive patients with BPH underwent transrectal CEUS before and 90 min after administration of 20 mg, Tadalafil. CEUS was performed during bolus injection of SonoVue (4.8 ml) using a nondestnictive US mode. The same scan plane, imaging parameters and technique were used before and after Tadalafil administration. Digital clips were recorded and processed using dedicated software (QontraXt v.3.60. Signal intensity (SI) changes in a region of interest (ROI) encompassing the entire prostate were fitted to a gamma-variate curve. Changes in enhancement peak, time to peak (TTP), sharpness of the bolus transit and area under the curve (AUC) were considered for further analysis. Results. After Tadalafil administration, the enhancement peak and AUC increased significantly (p<0.01), reflecting changes in prostate vascularity. TTP and sharpness did not change significantly. Conclusions. In patients with BPH, vascular changes are observed in the prostate after Tadalafil administration, which can be detected with CEUS.