Combined treatment with solifenacin and mirabegron is more effective than either medication alone in managing severe overactive bladder (OAB) in elderly patients, according to a new study. The risk of side effects with the combination treatment did not increase over monotherapy.
Russian investigators led by Kirill Kosilov, MD, of Far Eastern Federal University, compared OAB treatments over 6 weeks in 143 women and 95 men (ages 65 and older) with severe OAB symptoms, such as 3 or more incontinence episodes daily. The researchers randomly assigned patients to 4 treatment groups: mirabegron alone (50 mg/day); solifenacin alone (10 mg/day); placebo; or a combination of the 2 medications given simultaneously at the same dosages.
All patients completed bladder diaries and questionnaires on OAB symptoms and were examined via cystometry. During the study, the researchers determined that 64% of patients had detrusor overactivity incontinence, 23% had phasic detrusor overactivity, and 12% had terminal detrusor overactivity.
Over 6 weeks, all active drug treatments showed some efficacy in reducing OAB symptoms, according to findings published online ahead of print by the Archives of Gerontology and Geriatrics. Combination therapy was associated with the largest benefit:
- Incontinence decreased from 5.1 to 1.6 episodes a day, on average
- Urination decreased from 9.1 to 5.3 instances a day
- Post-void residual urine increased from 19.4 to 29.9 mL
Solifenacin, an antimuscarinic, and mirabegron, an agonist of β3-adrenoreceptors, probably work synergistically to suppress afferent noise and improve detrusor function, according to the researchers. Treatment with either drug alone may be insufficient to manage severe OAB symptoms in elderly patients, they noted. Reported side effects of the combination therapy included dry mouth, increased blood pressure, and elevated heart rate.
For this study, standard doses of the OAB medications were used for the combination therapy; however, future research should look at optimal dosages and duration of treatment, according to the investigators.
- Kosilov, KD, Loparev, A, Ivanovskaya, MA, and Kosilova, LV. Archives of Gerontology and Geriatrics; doi: 10.1016/j.archger.2015.06.006.