Beta-3 adrenoceptor agonist (bladder relaxant) 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

Mirabegron is an oral beta-3 adrenoceptor agonist used to treat the symptoms of overactive bladder, namely urgency, increased frequency and urgency urinary incontinence, offering an alternative to antimuscarinics.

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. Some sections of the product information we used were incomplete — check the full SPC.

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 independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. 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
This interaction list may be incomplete — check the full SPC.

Clinical monograph

How it works

It stimulates beta-3 adrenoceptors in the detrusor smooth muscle, promoting bladder relaxation during the storage phase and increasing functional bladder capacity.

Prescribing in practice

Mirabegron can raise blood pressure and is contraindicated in severe uncontrolled hypertension, so measure blood pressure before and during treatment.
It inhibits CYP2D6, so it can increase exposure to substrates with a narrow margin such as some antiarrhythmics and certain antidepressants; review interacting medicines.
Dose reduction or avoidance applies in significant renal or hepatic impairment per the SPC.

Monitoring

Monitor blood pressure regularly, particularly in patients with pre-existing hypertension, and review symptom response.

Counselling the patient

Take once daily, swallowing the tablet whole with water.
Have your blood pressure checked, and seek urgent help for the rare symptoms of urinary retention (inability to pass urine) or facial/throat swelling.

Evidence & guidelines

Mirabegron is recommended by NICE as an option for overactive bladder, supported by randomised trials showing reduced incontinence episodes and frequency.

Reference: NICE NG123; EAU Guidelines; NICE TA290; 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

Pathways