Trade Name(s)

  • Myrbetriq

Ther. Class.
urinary tract antispasmodics

Pharm. Class.
beta-adrenergic agonists


Treatment of symptoms of overactive bladder (OAB) including urge urinary incontinence, urgency, and frequency (either alone or with solifenacin).


  • 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 Effect(s):

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:

  • Hypersensitivity;
  • Severe uncontrolled hypertension;
  • End-stage renal disease or severe hepatic impairment (Child-Pugh Class C);
  • Lactation: Probably enters breast milk and may cause adverse reactions in infant.

Use Cautiously in:

  • Hypertension;
  • Bladder outlet obstruction/concurrent antimuscarics (↑ risk of urinary retention);
  • Concurrent use of antimuscarinics used to treat OAB;
  • OB:  Use only if potential maternal benefit outweighs risk to fetus;
  • Pedi:  Safety and effectiveness not established.

Adverse Reactions/Side Effects

CV: ↑ BP, tachycardia

EENT: nasopharyngitis

GI: constipation, diarrhea, nausea

GU: urinary tract infection

Neuro: dizziness, headache


* CAPITALS indicate life-threatening.
Underline indicate most frequent.



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


PO (Adults): 25 mg once daily; may be ↑ to 50 mg once daily based on need/tolerance after 8 wk.

Renal Impairment 
PO (Adults):  CCr 15–20 mL/min– Should not exceed 25 mg/day.Hepatic Impairment 
PO (Adults):  Moderate hepatic impairment (Child-Pugh Class B)– Should not exceed 25 mg/day.


Extended-release tablets: 25 mg, 50 mg


  • Assess patient for urinary urgency, frequency, and urge incontinence periodically during therapy.
  • Monitor BP prior to starting and periodically during therapy; may cause ↑ BP.
  • Monitor for signs and symptoms of angioedema (swelling of face, lips, tongue and/or larynx). Discontinue mirabegron and treat symptomatically.

Potential Diagnoses


  • PO 

    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.

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Anesthesia Central is an all-in-one web and mobile solution for treating patients before, during, and after surgery. This collection of drugs, procedures, and test information is derived from Davis’s Drug, MGH Clinical Anesthesia Procedures, Pocket Guide to Diagnostic Tests, and PRIME Journals. .