Mirabegron
MYRBETRIQ
Pronunciation: mir-a-BEG-ron (meer-BE-trik)
“Mirror be tricky, Mirror be growin”
bladder mascot → treatment for overactive bladder
What it isBeta-3 adrenergic agonist relaxing the detrusor; overactive bladder.
Why this oneIt can be combined with solifenacin when either mechanism alone fails, avoiding a full antimuscarinic burden.
What limits itIt raises blood pressure and moderately inhibits CYP2D6, which matters with metoprolol, flecainide and other narrow-index substrates.
FDA-approved for
- overactive bladder (2012)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Overactive bladder (OAB) | Adult | 25 mg QD | 25–50 mg QD (may ↑ after 4–8 wk) | 50 mg QD |
| OAB | Severe renal impairment (eGFR 15–29) | 25 mg QD | 25 mg QD | |
| OAB | Moderate hepatic impairment (Child-Pugh B) | 25 mg QD | 25 mg QD |
Titration May increase from 25 mg to 50 mg once daily after 4 to 8 weeks
Renal eGFR 30–89: no adjustment; eGFR 15–29: max 25 mg QD; eGFR <15 or dialysis: not recommended
Hepatic Child-Pugh A: no adjustment; Child-Pugh B: max 25 mg QD; Child-Pugh C: not recommended
ER tablets and ER oral suspension are not substitutable mg-per-mg
Instructions
- Swallow ER tablet whole with water; do not chew, divide, or crush; take with or without food
- Take a missed dose when remembered unless >12 h have passed; then skip it
Available strengths
- ER tab 25, 50 mg
- ER susp 8 mg/mL
- susp 8 mg/mL
Cautions
- Increases in blood pressure — monitor periodically; not recommended in severe uncontrolled hypertension
- Urinary retention in bladder outlet obstruction and with muscarinic antagonist drugs for OAB
- Angioedema of face/lips/tongue/larynx (may be life-threatening)
- Moderate CYP2D6 inhibitor — monitor narrow-therapeutic-index CYP2D6 substrates
Adverse reactions
- Hypertension
- Nasopharyngitis
- Urinary tract infection
- Headache
- Tachycardia
- Constipation
Pregnancy No human data; animal studies show reversible skeletal variations, reduced fetal weight, and cardiac findings (rabbit) at high multiples of the MRHD
Lactation No human data; present in rat milk; weigh benefits against maternal need
Cost
Generic entry2024
NO BOXED WARNINGS
Principal riskHypertension; a moderate CYP2D6 inhibitor
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
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