(mye-ra-beg-ron) ,


(trade name)


Therapeutic: urinary tract antispasmodics
Pharmacologic: beta adrenergic agonists
Pregnancy Category: C


Treatment of symptoms of overactive bladder (OAB) including urge urinary incontinence, urgency, and frequency.


Acts as a selective beta-3 adrenergic agonist.
Increases bladder capacity by relaxing detusor smooth muscle during storage phase of bladder fill-void cycle.

Therapeutic effects

Decreased symptoms of OAB.


Absorption: 29–35% absorbed following oral administration.
Distribution: Widely distributed.
Metabolism and Excretion: Extensively metabolized, 6% excreted unchanged in urine (25 mg dose), remainder excreted in urine and feces as metabolites.
Half-life: 50 hr.

Time/action profile (effects on bladder)

POunknown3.5 hr†24 hr
†Blood level.


Contraindicated in: Severe uncontrolled hypertension; Lactation: Probably enters breast milk and may cause adverse reactions in infant;End-stage renal disease or severe hepatic impairment (Child-Pugh Class C).
Use Cautiously in: Hypertension;Bladder outlet obstruction/concurrent antimuscarics (↑ risk of urinary retention);Concurrent use of antimuscarinics used to treat OAB; Obstetric: Use only potential maternal benefit outwieghs risk to patient/fetus; Pediatric: Safe and effective use in children has not been established.

Adverse Reactions/Side Effects

Central nervous system

  • dizziness
  • headache

Ear, Eye, Nose, Throat

  • nasopharyngitis


  • ↑ BP
  • tachycardia


  • constipation
  • diarrhea
  • nausea


  • urinary tract infection


Drug-Drug interaction

Acts as a moderate inhibitor of the CYP2D6 enzyme system.May ↑ levels and risk of adverse reactions of drugs metabolized by the the CYP2D6 enzyme system including desipramine, flecainide, metoprolol, propafenone, and thioridazine clinical/blood level monitoring recommended.May ↑ levels and risk of toxicity with digoxin (use lowest effective level of digoxin/monitor serum levels).


Oral (Adults) 25 mg once daily initially is usually effective within 8 wk, may be ↑ to 50 mg once daily based on need/tolerance.

Renal Impairment

Oral (Adults) Severe renal impairment (CCr15–20 mL/min)—dose should not exceed 25 mg/day.

Hepatic Impairment

Oral (Adults) Moderate hepatic impairment (Child-Pugh Class B)—dose should not exceed 25 mg/day.


Extended-release tablets: 25 mg, 50 mg

Nursing implications

Nursing assessment

  • Assess patient for urinary urgency, frequency, and urge incontinence periodically during therapy.
  • Monitor BP prior to starting and periodically during therapy; may cause ↑ BP.

Potential Nursing Diagnoses

Impaired urinary elimination (Indications)
Urinary retention (Indications)


  • Oral: Administer without regard to food.
    • Swallow tablets whole with water; do not break, crush, or chew.

Patient/Family Teaching

  • Instruct patient to take mirabegron as directed. If a dose is missed, omit dose and begin taking next day; do not take 2 doses on the same day. Advise patient to read Patient Information sheet prior to starting and with each Rx refill in case of changes.
  • Inform patient that mirabegron may cause an increase in BP. Advise patient to have BP checked periodically during therapy.
  • May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Advise patient to notify health care professional if difficulty emptying bladder occurs.
  • Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
  • Advise female patients to notify health care professional if pregnancy is planned or suspected or if breast feeding.

Evaluation/Desired Outcomes

  • Decreased urinary frequency, urgency, and urge incontinence.
References in periodicals archive ?
Another study showed that a drug called Mirabegron could also help create brown fat.
Updated recommendations for the diagnosis and treatment of nonneurogenic overactive bladder incorporate two new treatments approved since 2012--oral mirabegron and intradetrusor injection of onabotulinumtoxinA.
Drugs that won FDA approval in 2012 include lorcaserin hydrochloride (Belviq) to treat overweight and obsesity, mirabegron (Myrbetriq) for overactive bladder, and linaclotide (Linzess) to treat idiopathic constipation and irritable bowel syndrome with constipation in adults.
Drugs that won FDA approval in 2012 include lorcaserin hydrochloride (Belvig) to treat overweight and obesity, mirabegron (Myrbetrig) for overactive bladder, and linaclotide (Linzess) to treat idiopathic constipation and irritable bowel syndrome with constipation in adults.
What is the potential for novel therapies, such as Allergan's Botox and Astellas's mirabegron, in the competitive urinary incontinence market?
Even within the mirabegron group, there was a difference between naive (19% persistence) versus experienced patients (30% persistence).
TSE: 4503) announced today that results from its Phase 3b BESIDE clinical trial demonstrated solifenacin (SOLI) with mirabegron (MIRA) as an add-on therapy (ADD-ON) was superior to solifenacin monotherapy in incontinent overactive bladder (OAB) patients.
A global Phase 3 programme is now underway evaluating the safety and efficacy of the concomitant use of solifenacin (known commercially as VESICARE(TM)) and mirabegron (known commercially as BETMIGA(TM)), for the treatment of overactive bladder.
The animal data for mirabegron (Myrbetriq; antispasmodic for overactive bladder) suggest low risk.
A Food and Drug Administration panel voted 7-4 with 1 abstention that the overall benefit-risk assessment supports the approval of mirabegron for the treatment of overactive bladder.