Efficacy and tolerability of combined medication of two different antimuscarinics for treatment of adults with idiopathic overactive bladder in whom a single agent antimuscarinic therapy failed

Abstract

OBJECTIVE: Recent studies have investigated a combination of two antimuscarinics for adult neurogenic bladder managed with clean intermittent catheterization or pediatric refractory overactive bladder (OAB). We assessed the efficacy and tolerability of this strategy in adults with idiopathic OAB. METHODS: We reviewed 49 patients with idiopathic OAB who received combined antimuscarinic medication. Patients had serially received different kinds of antimuscarinics as monotherapy, but wished to take combined medication due to a lack of sufficient subjective improvement in urgency, even with dosage escalation. Efficacy was measured by changes of episodes of urgency, daytime voiding, nocturia and mean voided volume before and after the addition of the second antimuscarinic. RESULTS: The mean duration of combined medication was 9.3 months. After adding the second antimuscarinic, urgency per day decreased from 3.8 to 1.9 (p < 0.001) and daytime voiding decreased from 10.4 to 7.4 (p < 0.001). The number of nocturia episodes and the mean voided volume also improved, although there was no statistical significance. Efficacy did not differ between the 29 cases, with non-selective and non-selective drugs and 20 cases with non-selective and M3 selective drugs. Thirty-three (67.3%) patients reported to have benefited from combined medication. Maximal flow rate and post-void residual volume did not change in either of the sexes. Eleven (22.4%) patients discontinued the combination due to continued ineffectiveness and dry mouth. CONCLUSION: This retrospective study suggests that combined medication can help adults with refractory idiopathic OAB. Combined medication was tolerated in most of our patients.