Purpose: We measured the detailed hemodynamic effects of tamsulosin and sildenafil separately and together in patients with benign prostatic enlargement.
Materials and methods: The supine effects of and responses to passive orthostasis (60 degrees for 8 minutes) were measured in 16 patients with benign prostatic enlargement with the finger blood pressure method and whole-body impedance cardiography. The medications, 100 mg sildenafil (single doses) and 0.4 mg tamsulosin (once daily for up to 14 days), were administered in a randomized, double-blind, crossover fashion.
Results: Supine systolic arterial pressure decreased with sildenafil (mean +/- SEM -11 +/- 2 mm Hg) and sildenafil plus tamsulosin (-14 +/- 2 mm Hg) more than with placebo (-2 +/- 4 mm Hg, p <0.05). In comparison to placebo sildenafil plus tamsulosin decreased the systemic vascular resistance index (328 +/- 129 vs -241 +/- 134 dyn.sec/cm.m, p = 0.01). Tamsulosin alone did not cause any significant changes in comparison to placebo. Heart rate, diastolic arterial pressure, stroke index, cardiac index and arterial pulse wave velocity were not affected to a statistically significant degree by any of the treatments compared to placebo. Upon head-up tilt the drugs caused only 1 significant change in that diastolic arterial pressure was significantly higher (-2.7 vs -8.0 mm Hg, p = 0.04) in the placebo group than in the tamsulosin plus sildenafil group.
Conclusions: Tamsulosin does not disturb hemodynamics in patients with benign prostatic enlargement. Sildenafil decreases blood pressure with the patient supine but not during head-up tilt. The combination treatment also decreases the systemic vascular resistance index in the supine position.