mirabegron

mirabegron

(mye-ra-beg-ron) ,

Myrbetriq

(trade name)

Classification

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

Indications

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

Action

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.

Pharmacokinetics

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)

ROUTEONSETPEAKDURATION
POunknown3.5 hr†24 hr
†Blood level.

Contraindications/Precautions

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

Cardiovascular

  • ↑ BP
  • tachycardia

Gastrointestinal

  • constipation
  • diarrhea
  • nausea

Genitourinary

  • urinary tract infection

Interactions

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).

Route/Dosage

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.

Availability

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)

Implementation

  • 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 ?
Based on pharmacotherapy, the global overactive bladder treatment market has been segmented into anticholinergics, Botox, mirabegron, neurostimulation, and others.
for the use of mirabegron in combination with solifenacin 5 mg.
Mirabegron is an oral [beta]3-adrenoreceptor agonist which has emerged as an alternative to antimuscarinics for the medical treatment of OAB.
A patient subset-analysis of the data were also included in the plenary presentation at AUA, showing vibegron reduced UUI and micturitions in patients previously treated for OAB symptoms with an anticholinergic or mirabegron, the only currently marketed beta-3 agonist.
Also in September, the FDA accepted a supplemental New Drug Application for review that seeks approval for the use of mirabegron in combination with solifenacin succinate 5 mg for the treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency.
M2 PHARMA-May 8, 2018-Astellas Pharma awarded US FDA approval for sNDA for mirabegron & solifenacin succinate combination for treating OAB
M2 EQUITYBITES-May 8, 2018-Astellas Pharma awarded US FDA approval for sNDA for mirabegron & solifenacin succinate combination for treating OAB
In these instances, and for some men with urinary incontinence, physicians may prescribe medications that relax the bladder, such as mirabegron (Myrbetriq[R]) and anticholinergic drugs--oxybutynin (Ditropan[R]), solifenacin (Vesicare[R]), and tolterodine (Detrol[R]) are examples.
Before initiation of BoNTA, all patients had a trial of at least one anticholinergic medication or mirabegron.
Although there have been no reports of the use of mirabegron during lactation, the characteristics of the drug - low molecular weight (about 397), long elimination half-life (50 hours), and moderate plasma protein binding (about 71%)--suggest that the drug will be excreted into milk, potentially in clinically significant amounts.
In this study, approximately half of the patients received previous treatment and continued to present symptoms, and this observation is similar to those of the MATRIX study, despite the current availability of drugs such as solifenacin and mirabegron.
Darifenacin, mirabegron, oxybutynin ER, solifenacin, tolterodine, and trospium were classified as FORTA C (Questionable; Caution), while oxybutynin IR and propiverine were classified as FORTA D (Avoid; Do not).