Do alpha1-adrenoceptor antagonists improve lower urinary tract symptoms by reducing bladder outlet resistance?
OBJECTIVE
To test the hypothesis that improvements of lower urinary tract symptoms (IPSS) upon treatment with an alpha-blocker are due to reduction of bladder outlet obstruction (assessed as the bladder outlet obstruction index, BOOI); relationships of either with free flow Q(max) were also explored.


METHODS
The database of a large placebo-controlled, randomized, double-blind study with the alpha-blocker tamsulosin was analyzed retrospectively. Patients were stratified into lower and upper halves according to baseline IPSS, Q(max) or BOOI and treatment-associated alterations thereof. In these strata differences between values for the other two parameters were analyzed, for example, improvement of IPSS and Q(max) were compared in patients with below and above median improvement of BOOI.


RESULTS
Patients with below and above median baseline for one parameter, for example, IPSS had rather similar values for the other two parameters, for example, Q(max) and BOOI. Likewise, patients based upon baseline strata for one parameter had rather similar improvements of the other two parameters. Most importantly, patients with below and above median treatment-associated improvements of one parameter, for example, BOOI exhibited only small if any difference for alterations of the other two parameters, for example, IPPS and Q(max).


CONCLUSIONS
We conclude that IPSS, free flow Q(max) and BOOI are only loosely related at baseline. More importantly, treatment-induced improvements of these parameters are also only loosely related. These data do question the hypothesis that alpha-blockers largely improve lower urinary tract symptoms by reducing bladder outlet obstruction and suggest that they may also act independent of prostatic smooth muscle tone.
Barendrecht
Maurits M
MM
Department of Pharmacology and Pharmacotherapy, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Abrams
Paul
P
Schumacher
Helmut
H
de la Rosette
Jean J M C H
JJ
Michel
Martin C
MC
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000187:drug effects / Q000503:physiopathology; D011467:Prostate / Q000187:drug effects* / Q000503:physiopathology; D011470:Prostatic Hyperplasia / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D012189:Retrospective Studies; D013449:Sulfonamides / Q000494:pharmacology / Q000627:therapeutic use*; D000077409:Tamsulosin; D016896:Treatment Outcome; D001748:Urinary Bladder Neck Obstruction / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D014555:Urination Disorders / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D014563:Urodynamics / Q000187:drug effects*
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D013449:Sulfonamides; D000077409:Tamsulosin