Beta-3 Adrenoceptor Agonist Pregnancy: Not recommended in women of childbearing potential not using contraception. There are no or limited data from use in pregnant women and animal studies have shown reproductive toxicity, so mirabegron is not recommended during pregnancy. Mirabegron is excreted in the milk of rodents and is predicted to be present in human milk; it should not be used during breast-feeding. There were no treatment-related effects on fertility in animals; the effect on human fertility has not been established.

Mirabegron

Brand names: Betmiga

This is mirabegron, an oral beta-3 adrenoceptor agonist for overactive bladder, used to reduce urgency, daytime frequency, nocturia and urgency incontinence, particularly where antimuscarinic side effects are problematic.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Overactive bladder in adults (including elderly patients): 50 mg once daily

Route: Oral — prolonged-release tablet taken with liquids, swallowed whole, not chewed, divided or crushed; for adult OAB it may be taken with or without food

Frequency: Once daily

Max: Adult OAB: 50 mg once daily is the recommended dose, reduced to 25 mg once daily in severe renal impairment (eGFR 15 to 29 mL/min/1.73 m²) or moderate hepatic impairment (Child-Pugh B), and to no more than 25 mg in mild/moderate renal impairment or mild hepatic impairment when a strong CYP3A inhibitor is co-administered. Paediatric neurogenic detrusor overactivity: maximum 50 mg once daily.

Missed dose: patients should take any missed dose unless more than 12 hours have passed, in which case the missed dose can be skipped and the next dose taken at the usual time. Mirabegron can increase blood pressure — measure blood pressure at baseline and periodically during treatment, especially in hypertensive patients; data are limited in stage 2 hypertension (systolic 160 mmHg or more, or diastolic 100 mmHg or more). Administer with caution to patients with clinically significant bladder outlet obstruction and to patients taking antimuscarinic medicines for OAB, because of reports of urinary retention. Caution in patients with known QT prolongation or taking QT-prolonging medicines. PAEDIATRIC (neurogenic detrusor overactivity, non per-kg so not expressible as a mg/kg dose, hence paedDose is null): patients 3 to less than 18 years with NDO may be given prolonged-release tablets if weighing 35 kg or more, while granules for prolonged-release oral suspension are recommended below 35 kg; the recommended starting dose of the prolonged-release tablets is 25 mg once daily with food, increased if needed to a maximum of 50 mg once daily with food after 4 to 8 weeks; patients on a 6 mL oral suspension dose may be switched to a 25 mg tablet dose and those on a 10 mL oral suspension dose to a 50 mg tablet dose; the tablet must be taken with food in this indication; safety and efficacy below 3 years of age have not been established, and for OAB in children under 18 no posology recommendation can be made. Blood pressure increases may be larger in children (3 to less than 12 years) than in adolescents. During long-term therapy patients should be periodically evaluated for treatment continuation and potential dose adjustment, at least annually. Verify any under-18 use against a children's formulary. The fetched SPC product is Mirabegron Astellas 25 mg prolonged-release tablets, whose section 4.2 gives 50 mg once daily as the recommended adult OAB dose. Section 4.5 (interactions) was cut off at the source-fetch limit in this bundle.

Dose adjustments

Renal

Adult OAB daily dosing (SPC section 4.2, Table 1): mild/moderate renal impairment (eGFR 30 to 89 mL/min/1.73 m²) — 50 mg; severe renal impairment (eGFR 15 to 29 mL/min/1.73 m²) — 25 mg; end stage renal disease (eGFR less than 15 mL/min/1.73 m²) or requiring haemodialysis — not recommended. In mild to moderate renal impairment with a concomitant strong CYP3A inhibitor the recommended dose is no more than 25 mg, and mirabegron is not recommended in severe renal impairment with a strong CYP3A inhibitor. Hepatic impairment: mild (Child-Pugh A) 50 mg; moderate (Child-Pugh B) 25 mg; severe (Child-Pugh C) not recommended.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Severe uncontrolled hypertension, defined as systolic blood pressure 180 mmHg or more and/or diastolic blood pressure 110 mmHg or more

Side effects

Urinary tract infection (common) and tachycardia (common) — the most common adverse reactions with mirabegron 50 mg (UTI 2.9%, tachycardia 1.2%)
Vaginal infection, cystitis, palpitation, headache, dizziness (uncommon)
Nausea, constipation, diarrhoea, dyspepsia, gastritis (uncommon)
Urticaria, rash, pruritus, joint swelling, eyelid oedema (uncommon)
Atrial fibrillation (uncommon; reported as a serious adverse reaction in 0.2%) and increased blood pressure
Post-marketing: hypertensive crisis, urinary retention, angioedema, confusional state, insomnia

Interactions

Strong CYP3A inhibitors — in mild to moderate renal impairment or mild hepatic impairment the recommended dose is no more than 25 mg; not recommended for use in severe renal impairment or moderate hepatic impairment when a strong CYP3A inhibitor is co-administered (SPC sections 4.2 and 4.4)
Antimuscarinic medicinal products for OAB — administer mirabegron with caution because of reports of urinary retention (SPC section 4.4)
Medicinal products known to prolong the QT interval — caution, as such patients were excluded from the QT studies (SPC section 4.4)
From the US label section 7 (cross-check only): mirabegron is a CYP2D6 inhibitor — when used with drugs metabolised by CYP2D6, especially narrow therapeutic index drugs, appropriate monitoring and possible dose adjustment of those drugs may be necessary
From the US label section 7 (cross-check only): digoxin — when initiating the combination use the lowest digoxin dose and monitor serum digoxin concentrations
Note: the eMC section 4.5 interactions text was cut off at the source-fetch limit and must be checked in full against the SPC

Clinical monograph

How it works

By activating detrusor beta-3 adrenoceptors it relaxes the bladder wall during filling, improving storage symptoms without the dry mouth and constipation typical of antimuscarinics.

Prescribing in practice

Because it can increase blood pressure, it must not be used in severe uncontrolled hypertension and blood pressure should be checked at baseline and on treatment.
It is generally better tolerated than antimuscarinics in older people but should still be used cautiously where there is bladder outflow obstruction or concomitant antimuscarinics, given a risk of urinary retention.
As a moderate CYP2D6 inhibitor it can raise levels of narrow-margin substrates, so screen for interactions.

Monitoring

Monitor blood pressure during therapy and reassess overactive-bladder symptoms after an adequate trial.

Counselling the patient

Take once daily with water, with or without food.
Report inability to pass urine or any swelling of the face, lips or throat promptly.

Evidence & guidelines

NICE supports mirabegron for overactive bladder when antimuscarinics are unsuitable, ineffective or poorly tolerated, based on trial evidence of symptom improvement.

Reference: NICE NG123; SCORPIO trial; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Mirabegron (Overactive Bladder — Elderly) · Beta-3 Adrenoceptor Agonist

Pathways