Multiple sclerosis (MS) is the commonest progressive neurological disorder affecting young people. Lower urinary tract symptoms (LUTS) are reported by over 80% of patients with MS, occurring during the early stages of the disease and sometimes might be reported at initial presentation. LUTS progressively worsen, and become more difficult to manage with increasing disability. Furthermore, LUT symptoms negatively influence patients’ quality of life [1]. 
Patients with MS can present with a wide range of LUTS. Of these, symptoms of the storage phase (overactive bladder symptoms) are the most frequently reported, with urgency observed in 38–99% of patients, frequency in 26–82% and urge incontinence in 27–66%. By contrast, symptoms of the voiding phase are less frequent, with a prevalence of 6–49%, while symptoms of both the storage and voiding phases can coexist in 50% of patients [1]. 
Herein, we present the initial results of our original ongoing study on treating overactive bladder (OAB) symptoms in MS patients with mirabegron compared to solifenacin and evaluate their efficacy with MSQoL and NBSS.

We enrolled 45 patients with MS and OAB: 34 male and 11 female patients, with mean age 43.3 years (range 21-75), mean time from MS diagnosis was 5.7 years (range 0.5-37), while time from OAB symptoms onset was 3.1 years (0.5 to 16). All patients enrolled at the day of enrollment filled the MSQoL and NBSS questionnaires, asked to fill a bladder diary for at least three consecutive days and prescribed an ultra-sonogram (US) of bladder and kidneys in order to evaluate post-void urine volume and pelvicalyceal dilatations and a urine culture in order to exclude any bacteriuria. In case of sterile urine culture, absence of dilatation and residual urine volume <150cc, patients were divided in two groups: group A,  with 23 patients, received 50mg of mirabegron and group B, with 22 patients received 10mg of solifenacin. Patients were planned to visit hospital in one and three months for follow up, in order to evaluate their progress. In the 3rd month visit, patients were offered a second US so as to evaluate residual urine and upper urinary tract status and filled again MSQoL, NBSS and bladder diary.

Mean initial residual volume was 21.1 cc, while two patients had 253cc and 500cc and offered clean intermittent self-catheterizations (CISC). All patients were free from upper tract dilatations, except from one. Regarding bladder diary, mean number of urinations was 12.2  (range 10-22) with 80% of them characterized by urgency and mean volume per urination was 131.3cc (range 20-300). Mean MSQoL(1-12) was 29.7 (range 3-48), mean MSQoL(13-22) was 24.7 (range 14-33) and mean MSQoL(23-31) was 20.2 (range 14-30). Mean NBSS-Incontinence was 7.5 (range 0-18), mean NBSS-Storage/Voiding was 7.5 (range 0-18) and mean NBSS-Consequences was 7.9 (range 1-18), while mean NBSS-QoL was 1.9 (range 0-4).
At 3 months patients of both groups showed improvement in all measured values. In group A, patients showed significant improvement (p<0.001) in urinations characterized by urgency, in NBSS-Incontinence and NBSS-Storage/Voiding. In group B, patients showed significant improvement (p<0.001) in urgency and NBSS-Storage/Voiding (p=0.01). No patients had to discontinue either medication due to side effects.

Antimuscarinic drugs, especially the more selective ones such as solifenacin with their higher affinity for the M3 receptor, are the current standard first-line pharmacotherapy for OAB. However, although these agents are generally effective, some patients experience a suboptimal response to treatment or experience frequent, bothersome adverse events (AEs), the most common of which is dry mouth [2]. B3 agonists, such as mirabegron, by promoting urine storage in the bladder inducing detrusor relaxation, are effective and well tolerated regimens [3]. Although there have not yet been studies for OAB treatment especially in MS patients, both anticholinergics and β3-agonists seem reasonable treatment options for these patients. Our study’s results are in accordance with the literature. Although our sample is relatively small, we have shown that both regimens improve OAB symptoms and there is a trend favoring mirabegron.

Both mirabegron and solifenacin improve OAB symptoms in MS patients, in certain sections of validated questionnaires and suggest safe and effective treatment options.

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