What is myrbetriq used for?
Overactive bladder (OAB) affects about 1 in 6 adults, causing urinary frequency, urgency, and incontinence. Myrbetriq (mirabegron) treats OAB symptoms in adults. The usual starting dose is 25 mg orally once daily, which may be increased to 50 mg after 1–2 months if needed. It can be used alone or with 5 mg Vesicare (solifenacin).
Myrbetriq is also FDA-approved for neurogenic detrusor overactivity (NDO) in children ≥ 3 years. Dosing is weight-based:
- Children ≤ 35 kg: 24–64 mg granules once daily
- Children > 35 kg: 25 mg tablet (up to 50 mg) or 48 mg granules (up to 80 mg) once daily
Dosing adjustments may be needed for liver or kidney impairment.
How does Myrbetriq work?
Myrbetriq is a beta‑3 agonist that relaxes bladder muscles by activating beta‑3 receptors, increasing bladder capacity and reducing urgency and frequency.
Major side effects of Myrbetriq
Adults with OAB:
- Common cold symptoms
- High blood pressure
- Urinary tract infection
- Dry mouth
- Fast heartbeat
- Headache
Children with NDO:
- Urinary tract infection
- Common cold symptoms
- Headache
- Constipation
- Nausea
Serious side effects (seek immediate help):
- Urinary retention (especially with bladder outlet obstruction or other OAB medications)
- Atrial fibrillation
- Severe allergic reaction (angioedema, hives, breathing difficulty)
- Eye problems (glaucoma, blurry vision)
Drug interactions
- Digoxin
- Metoprolol
- Thioridazine
- Flecainide
- Propafenone
- Desipramine
Who should not take Myrbetriq?
- Allergy to mirabegron or inactive ingredients
- Uncontrolled high blood pressure
- Bladder outlet obstruction
- Severe kidney or liver problems
- History of angioedema
- Pregnancy or breastfeeding without provider approval
How to take Myrbetriq
Extended-release tablet: swallow whole once daily with water, with or without food (adults). Granule suspension (children): shake bottle 1 minute, let settle 1–2 minutes, measure with provided device, take with food, then wash device and let air dry.
Storage: tablets at 68–77 °F (20–25 °C); granule suspension at 68–77 °F for up to 28 days.
If you miss a dose
If within 12 hours, take as soon as you remember. If > 12 hours, skip and resume next scheduled dose. Do not double dose.
Sources
- Myrbetriq (mirabegron extended-release tablets; granules). Astellas Pharma US, Inc. Last updated 4/2021. Accessed Apr 15, 2025.