Tamsulosin in men with confirmed bladder outlet obstruction: a clinical and urodynamic analysis from a single centre in New Zealand

Objective To evaluate the clinical and pressure‐flow effects of tamsulosin 0.4 mg once daily in patients with lower urinary tract symptoms (LUTS) caused by benign prostatic obstruction (BPO), as documented by pressure‐flow studies performed according to a standardized protocol in one centre. Patients and methods A single‐centre study was conducted with an open‐label design comprising a 2‐week, single‐blind, placebo run‐in period and a 12‐week active treatment period with tamsulosin 0.4 mg once daily. Eligible patients were men (aged 45 years) with LUTS (total International Prostate Symptom Score, IPSS, 13) with a free‐flow maximum urinary flow rate (Qmax) of 4 mL/s for a voided volume of 120 mL. After the 2‐week placebo run‐in period, only patients with BPO (i.e. in the obstructed zone of the Abrams‐Griffiths, AG, nomogram) received active treatment with tamsulosin. The two primary efficacy variables were the change in detrusor pressure at maximum flow (PdetQmax) and the total IPSS, from baseline to endpoint. A standardized protocol was used for all pressure‐flow studies. Results In all, 42 patients were enrolled into the 2‐week placebo run‐in period, after which 30 received active treatment with tamsulosin 0.4 mg once daily. All 12 patients (29%) who discontinued during the placebo run‐in period failed to fulfil the pressure‐flow entry criterion of confirmed obstruction. The 30 patients who received tamsulosin had a high mean PdetQmax (82.1 cm H2O) and high mean AG number (68.1) at baseline, as would be expected in obstructed patients. Tamsulosin produced a significant reduction in mean PdetQmax (− 10.6 cm H2O or −13%; P = 0.005 vs baseline). The mean AG number decreased accordingly (− 15.5 points or −23%; P