From the Guidelines
Mirabegron is not an anticholinergic medication, but rather a beta-3 adrenergic receptor agonist that works by relaxing the detrusor muscle in the bladder through a different mechanism than anticholinergic drugs. According to the 2023 European Association of Urology guidelines on the management of non-neurogenic male lower urinary tract symptoms 1, mirabegron is the only beta-3 agonist licensed in Europe for MLUTS management. The guidelines highlight that mirabegron monotherapy improves frequency, urgency, and UUI episodes compared with placebo or tolterodine. Some key points about mirabegron include:
- It is well tolerated in the elderly and in patients with multiple comorbidities, although it is contraindicated in patients with severe uncontrolled hypertension 1
- The most frequent adverse effects are hypertension, UTIs, headache, and nasopharyngitis 1
- Mirabegron does not affect voiding urodynamic parameters, and the overall change in PVR is small 1 This distinction is clinically important because mirabegron typically causes fewer anticholinergic side effects such as dry mouth, constipation, and cognitive impairment, making it a good alternative for patients who cannot tolerate anticholinergic side effects or for elderly patients who are at higher risk for cognitive issues with anticholinergic medications.
From the FDA Drug Label
Mirabegron is an agonist of the human beta-3 adrenergic receptor (AR) as demonstrated by in vitro laboratory experiments using the cloned human beta-3 AR.
Mirabegron is not an anticholinergic medication. It works by activating the beta-3 adrenergic receptor, which increases bladder capacity. There is no mention of anticholinergic properties in the provided drug labels 2, 3, or 4.
From the Research
Mirabegron Mechanism of Action
- Mirabegron is a novel β3-adrenoceptor agonist, which reduces bladder muscle contractions 5, 6, 7
- It has a different mechanism of action compared to anticholinergic drugs, which makes it an alternative for patients who are intolerant of or have contraindications to anticholinergics 6, 7, 8
Comparison with Anticholinergics
- Mirabegron has a similar efficacy profile to first-line antimuscarinics, but with a more favorable adverse effects profile 9, 8
- It has a lower incidence of dry mouth compared to antimuscarinics, such as tolterodine 5, 7, 8
- Mirabegron can be used as a second-line treatment for overactive bladder (OAB) in patients who are poor responders or intolerant to anticholinergics 5