Several studies have demonstrated the efficacy and safety of anti-muscarinics in male patients with lower urinary tract symptoms (LUTS), but few have evaluated their effects on post-void residual urine volumes (PVR) in men at higher risk for developing retention.
To evaluate the short-term effects of anti-muscarinic agents on PVR in men with LUTS and who are at higher risk of developing urinary retention.
28 high risk male patients (mean age 65 years, range 21 to 91 years) were evaluated. High risk was defined as men with LUTS with urodynamically demonstrated bladder outlet obstruction (BOO) [group 1, n=4]; and both BOO and PVR>100 ml [group 2, n=5]; those with neurogenic bladder (NGB) [group 3, n=11]; NGB with BOO [group 4, n=3] and NGB with BOO and PVR > 100ml [group 5, n=5]. Patients were treated with FDA-approved anti-muscarinic agents. A clinically significant increase in PVR was defined as an increase of > 100 ml and/or that requiring catheterization. 7 of the 28 men were on concomitant alpha1-receptor antagonists.
The mean follow-up was 9 months (range 1 to 32 months). For all patients, the mean PVR increased from a baseline of 60.6 ml to 87.0 ml. (p>0.05) A clinically significant increase in PVR occurred in 5 of 28 patients (17.9%): 0 [group 1], 2 [group 2], 1 [group 3], 0 [group 4], and 2 [group 5], respectively. No patients required catheterization. In these 5, the mean increase in PVR was 145.9 ml. 1 out of the 5 was clinically improved and continued on medication. 3 of 28 patients (10.7%) discontinued therapy due to an elevated PVR.
Anti-muscarinic agents may increase PVR in men with LUTS and who are at higher risk of developing urinary retention. Discontinuation of medication due to an elevated PVR occurs in a minority of cases. Studies with larger cohorts of patients and longer-term follow-up are recommended.