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Beta-3 Adrenoceptor Agonist

Mirabegron (Overactive Bladder — Elderly)

Brand names: Betmiga

Mirabegron is a beta-3 adrenoceptor agonist used for overactive bladder, offering an alternative to antimuscarinics with a different side-effect profile.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Mirabegron extended-release tablets and mirabegron for extended-release oral suspension are two different products and they are not substitutable on a milligram-per-milligram basis. Select the recommended product (mirabegron extended-release tablets or mirabegron for extended-release oral suspension) based on the indication. OAB in Adults The recommended starting dose of mirabegron extended-release tablets is 25 mg orally once daily. ( 2.2 ) After 4 to 8 weeks, the mirabegron extended-release tablets dose may be increased to 50 mg orally once daily. ( 2.2 ) Adult Patients with Renal or Hepatic Impairment: Refer to the full prescribing information for recommended dosage. ( 2.4 ) …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-09-26. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It stimulates β3-adrenoceptors in the bladder to promote detrusor relaxation and increase bladder capacity.

Prescribing in practice

  • It can raise blood pressure — measure blood pressure before and during treatment, and avoid it in severe uncontrolled hypertension.
  • It avoids the anticholinergic effects of antimuscarinics, which can suit older patients.
  • It inhibits CYP2D6, with some resulting interactions.

Monitoring

Monitor blood pressure; review symptom response.

Counselling the patient

  • It does not cause the dry mouth that antimuscarinic bladder drugs do.
  • Your blood pressure will be checked.
  • Report severe headache or palpitations.

Evidence & guidelines

An option for overactive bladder, especially where antimuscarinics are unsuitable, with blood-pressure monitoring (NICE NG123/TA290).

Reference: NICE CG171 (Urinary Incontinence in Women); MHRA Drug Safety Update 2021 (anticholinergic drugs and dementia); AGS Beers Criteria 2023; STOPP/START v3; MHRA SPC Betmiga; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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