Combination of a cholinergic drug and an α‐blocker is more effective than monotherapy for the treatment of voiding difficulty in patients with underactive detrusor

AIM: The aim of the present study was to compare the effectiveness of a cholinergic drug, an alpha-blocker and combinations of the two for the treatment of underactive detrusor. METHODS: One hundred and nineteen patients with underactive bladder were assigned to three groups: the cholinergic group, consisting of 40 patients taking bethanechol chloride (60 mg/day) or distigmine bromide (15 mg/day); the alpha-blocker group, consisting of 38 patients taking urapidil (60 mg/day); and the combination group, consisting of 41 patients taking both a cholinergic drug and an alpha-blocker. The effectiveness of each therapy was assessed 4 weeks after initialization of the therapy. RESULTS: Total urinary symptom scores (International Prostate Symptom Score, IPSS) remained unchanged after the cholinergic therapy, but were significantly lower after the alpha-blocker treatment (P = 0.0001) and the combination therapy (P = 0.0001). With regard to the total IPSS, there were significant differences between the cholinergic and the alpha-blocker groups (P = 0.0008), and also between the cholinergic and combination groups (P = 0.0033), in favor of the latter. The average and maximum flow rates did not increase significantly after monotherapy with either the cholinergic drug or the alpha-blocker, but they significantly increased after combination therapy compared to baseline values (P = 0.0033 and P= 0.0004, respectively). Postvoid residual volume did not decrease significantly after the cholinergic drug therapy, but decreased significantly after the alpha-blocker (P = 0.0043) and the combination therapies (P = 0.0008). The percentage of residual urine decreased significantly after therapy in all groups (P = 0.0005, P= 0.0176 and P= 0.0001, respectively). CONCLUSION: Combination therapy with a cholinergic drug and an alpha-blocker appears to be more useful than monotherapy for the treatment of underactive detrusor.