mye-ra-BEG-ron

Therapeutic Classification: urinary tract antispasmodics

Pharmacologic Classification: beta-adrenergic agonists

• Overactive bladder (OAB), including urge urinary incontinence, urgency, and frequency (either as monotherapy or in combination with solifenacin).
• Pediatric neurogenic detrusor overactivity.

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

• Decreased symptoms of OAB.
• Improved bladder capacity in neurogenic detrusor overactivity.

Absorption: 29–35% absorbed following oral administration.

Distribution: Widely distributed.

Metabolism/Excretion: Extensively metabolized, 6% excreted unchanged in urine (25 mg dose), remainder excreted in urine and feces as metabolites.

Half-life: Adults: 50 hr; Children: 26–31 hr.

(effects on bladder)

†Blood level.

Contraindicated in:

• Hypersensitivity
• Severe uncontrolled hypertension
• End-stage renal disease (eGFR <15 mL/min/1.73 m² or requiring dialysis)
• Severe hepatic impairment.

Use Cautiously in:

• Hypertension
• Bladder outlet obstruction/concurrent antimuscarinics (↑ risk of urinary retention)
• Concurrent use of antimuscarinics used to treat OAB
• OB: Safety not established in pregnancy
• Lactation: Safety not established in breastfeeding
• Pedi: Children <3 yr (safety and effectiveness not established).

CV: ↑BP, tachycardia.

EENT: nasopharyngitis.

GI: constipation, diarrhea, nausea.

GU: urinary tract infection.

Neuro: dizziness, headache.
Misc: ANGIOEDEMA.

Drug-Drug:

• May ↑ levels and risk of toxicity of CYP2D6 substrates, including desipramine, flecainide, metoprolol, propafenone, and thioridazine.
• May ↑ levels and risk of toxicity with digoxin; use lowest effective level of digoxin/monitor serum levels).

Overactive Bladder

• PO (Adults): 25 mg once daily; may ↑ to 50 mg once daily, if needed, after 4–8 wk.

Neurogenic Detrusor Overactivity

• PO (Children 3 yr and 35 kg): Extended-release tablets: 25 mg once daily; may ↑ to 50 mg once daily, if needed, after 4–8 wk. Extended-release oral suspension (granules): 48 mg once daily; may ↑ to 80 mg once daily, if needed after 4–8 wk.
• PO (Children 3 yr and 22–<35 kg): Extended-release oral suspension (granules): 32 mg once daily; may ↑ to 64 mg once daily, if needed after 4–8 wk.
• PO (Children 3 yr and 11–<22 kg): Extended-release oral suspension (granules): 24 mg once daily; may ↑ to 48 mg once daily, if needed after 4–8 wk.

(Generic available)

• Extended-release tablets: 25 mg; 50 mg;
• Extended-release oral suspension (granules): 8 mg/mL;

• 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.

• Tablets and granules are different products. Do not interchange, substitute, or combine.

Overactive Bladder

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

Neurogenic Detrusor Overactivity

• Pediatric patients weighing 35 kg may use tablets or granules. Administer as an extended-release oral suspension once daily.
  • DNC: Swallow tablets whole with water; do not break, crush, or chew.
  • Administer granules for patients weighing <35 kg. Granules are prepared as an extended-release oral suspension with a concentration of 8 mg/mL. Shake bottle for 1 min then let stand until foam on top of suspension is gone (about 1–2 min). Administer within 1 hr after preparation with food once daily; do not save dose for later.

• Instruct patient to take mirabegron as directed. If a dose is missed, take as soon as remembered unless >12 hrs since missed dose. If >12 hrs since missed dose, omit dose and take next dose at scheduled time. 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 females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

• Decreased urinary frequency, urgency, and urge incontinence.

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