Intravesical Prostatic Protrusion does not compromise therapeutic effects of Mirabegron in male patients with overactive bladder.

Intravesical prostatic protrusion (IPP) is associated with degree of benign prostatic obstruction (BPO). We evaluated the effects of Mirabegron, a selective β3 adrenoceptor agonist, on overactive bladder (OAB) in male patients with different degrees of IPP.

185 male patients ≥ 40 years with lower urinary tract symptoms (LUTS) were recruited from a tertiary referral center. OAB was defined by OAB symptom score urgency score of ≥2 and sum score of ≥3. IPP was measured in the mid sagittal section using transrectal ultrasound and patients were divided into IPP≤5mm and IPP>5mm groups. Outcomes were assessed at baseline, four, and twelve weeks.

104 patients (56.2%) were diagnosed with OAB and received Mirabegron (50mg) daily use. Both IPP groups (≤5mm and >5mm) had similar baseline OAB Symptom Scores and International Prostate Symptom Scores (IPSS). Four-week Mirabegron usage was associated with significant decreases in both symptom score measurements, OABSS: IPP≤5mm -27.4% and IPP>5mm -19.7% (p=0.419) and IPSS: -32% and -22.5% (p=0.202), respectively. Urgency, urge incontinence and nocturia sub-scores were decreased in both groups, -26.3% and -27.4% (p=0.690), 53.3% and 46.2% (p= 0.916), and 20.8% and 15.4% (p=0.958). Effects were maintained at twelve weeks. We found no significant improvement in the frequency sub-score in either group. One patient stopped medication due to intolerable hypertension. Most frequent adverse event was increased residual urine (≥ 50 ml higher than baseline), IPP≤5mm 9.2% and IPP>5mm 5.1% (p= 0.707), but no case had acute urinary retention.

Mirabegron is an effective drug to treat male OAB regardless of IPP grade.

International journal of clinical practice. 2020 May 21 [Epub ahead of print]

Yuan Chi Shen, Hung Jen Wang, Wei Chia Lee, Chien Hsu Chen, Yao-Chi Chuang

Urology, DaPi Road No.123, Kaohsiung, Taiwan., Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan., Chang Gung Memorial Hospital, Kaohsiung, Taiwan.