This systemic review compared Anticholinergic medications with Beta-3- receptor agonist (Mirabegron) in management of patients with overactive bladder(OAB). The primary aim was to compare efficacy, adverse effects, persistence and adherence and cost effectiveness among these two groups of medications. Other properties considered included tolerability, effect in female OAB, combining two groups of medication in management of OAB.

Preferred Reporting Items for Systematic Review and Meta-analyses  guidelines (PRISMA) were followed for the conduct of this study . We used Healthcare Databases Advanced Search (HDAS) Export software to facilitate search in Medline and EMBASE, and also searched other databases from 2015 to 2020 . Searched terms included: “Overactive bladder”, “Muscarinic receptor antagonist”, “Anticholinergic drugs in overactive bladder”, “ Beta-3-receptor agonists in overactive bladder”, “Antimuscarinics drugs in overactive bladder” “ Detrusor receptors”, “Anticholinergic and Beta adrenergic agonists”, “Mirabegron”. Boolean operators included, “or” and “and”.
151 articles matched the initial search on Medline/EMBASE and the first 100 articles were considered from a search on Google scholar. After removing duplicates 103 articles remained.74 were screened, after excluding 21 studies, 53 full text articles were assessed for inclusion. Using the SQR3 (Survey, Question, Read, Recite, and Review) technique, 20 articles were included in the final qualitative analysis.

RESULTS
The results from the extended literature revealed following 
a.	Efficacy: Nine studies analyzed efficacy of these two groups of medications. Results from all the studies concluded that Mirabegron is as efficacious as any other anticholinergic. It has been found to decrease even post-void residual urine.
b.	Adverse Effects: Five studies compared adverse effects .They revealed that Mirabegron has less side effects as compared to antimuscarnics. Dry mouth as an adverse effect with Mirabegron is that of a placebo.
c.	Persistence and Adherence: Five studies have found that persistence as well as adherence is better with Mirabegron (Including median as well as yearly persistence/adherence)
d.	Cost Effectiveness: Three studies across globe have proven that Mirabegron is cost effective as compared to anticholinergics.
e.	Tolerability: Three studies established that Mirabegron has better tolerability as compared to Antimuscarnics. It has been found tolerable even in elderly as compared to Antimuscarnics.
f.	OAB in Females: Two studies involved female only patients. These results revealed that Mirabegron is a very good alternative to Antimuscarinics in OAB. 
g.	Combination Of Antimuscarinics and Mirabegron: Two recent research works have found that combination is providing better results. Most studies have found Mirabegron and Solifenacin as an excellent combination.
h.	Switching from Antimuscarnics to Mirabegron: One study has revealed that switching had excellent results in that group of patients in terms of efficacy, tolerability and A/E profile.
i.	Urodynamic results: One study found that there is improvement in UDS after change to Mirabegron in terms of Post-void volumes particularly in females.

The International Continence Society (ICS) has recommended use of the terms overactive bladder syndrome (OAB) and detrusor overactivity for a group of lower urinary tract symptoms. The term Detrusor overactivity (DA) is diagnosed on basis of urodynamic evaluation which reveal involuntary detrusor contractions occurring during storage phase. It is further classified into Idiopathic Detrusor Overactivity (IDO) and Neurogenic Detrusor Overactivity (NDO). ICS in 2002 introduced term OAB which is based on symptomatic diagnosis. OAB is characterized by urgency, with or without urge incontinence, and usually with frequency and nocturia . The ICS recommends endorsement of the term OAB recognizes that patients with this symptom syndrome are almost always treated by nonsurgical means on an empirical basis. The two most important classes of drugs used are Antimuscarnics and Beta adrenoreceptors.
Antimuscarnics drugs act by inhibiting the acetylcholine action (Ach) . Ach causes  acts on muscarinic receptors and stimulates detrusor contraction .Within parasympathetic system there are five different subtypes of muscarinic receptors. Only M2 and M3 receptors are present in bladder. Although, M2 is more frequent, it is M3 which is more involved in detrusor function .  Most of the anticholinergics have similar efficacy in terms of symptomatic relief .Side effect profile however varies depending on affinity of receptor, drug levels in serum and the mode of administration of drug ,Table 5.
There are 3 types of β-adrenoceptors ( β1,β2,β3)in bladder detrusor muscle as well as urothelial lining [24], β3 being most predominant of them [25]. β3 receptors excitation causes detrusor smooth muscle relaxation [26]. Mirabegron which is  β3 receptor agonist, has been extensively used as well as studied for treatment of OAB. Mirabegron has been found to be a safe, effective ,well-tolerated. As far as incidence of  dry mouth is concerned , it had similar results to placebo in almost all trials .
Our review reveals that Mirabegron is as efficacious as any other Antimuscarnics, has  better tolerability (Including Elderly),has better adverse effect profile, is cost effective, has better persistence and adherence rates at 12 months. However, this study had its limitations in terms of being a literary review, study being limited to last 5 years and only articles with full articles included.

To conclude, we found Mirabegron is efficacious and safe to be used as a first line therapy in OAB. In  future more research needs to be conducted in using combination of Mirabegron and Solifenacin in OAB, however, all such studies and trails must consider patient understanding and expectations factors which are essential in management of these patients.