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mirabegron

mirabegron

Introduction

  • mirabegron is a beta-3 receptor agonist agent which is primarily used in the Rx of overactive bladders, urgency and urge incontinence
  • the bladder wall muscle during the storage phase of bladder filling is mainly relaxed via beta 3 adrenergic stimulation, while the void phase is primarily via muscle contraction due to muscarinic M3 receptor stimulation
  • introduced into the Australian PBS in 2013
  • only recommended when antimuscarinic agents are C/I, ineffective or not tolerated

Usual adult dose

  • 25-50mg daily sustained released tablet
  • steady state concentrations are achieved within 7 days of once daily dosing with mirabegron and plasma levels are approximately double that seen after a single dose
  • Vd at steady state 1670 L
  • terminal elimination half life is 50hrs (25% renal)

C/I

  • uncontrolled hypertension (systolic > 180mmHg or diastolic > 110mmHg)
  • hypersensitivity to mirabegron or its ingredients - angioedema has been reported
  • high urinary retention risk esp. avoid combination with antimuscarinics if risk is high
  • severe hepatic disease
  • severe renal disease or dialysis
  • children
  • pregnancy - cat B3
  • lactation as it is expressed in breast milk
  • care with some medications as it does have some drug interactions such as digoxin, flecainide, tricyclic antidepressants - see product information

Adverse effects

  • most are mild effects and only 4% cease medication due to adverse reactions
  • mild increase in HR and BP (usually < 5mmHG)
  • nasopharyngitis, UTI, headaches occur in 3%
  • constipation, diarrhoea or tachycardia occur in 1-2%
  • atrial fibrillation in 1% - cease Rx
mirabegron.txt · Last modified: 2019/08/02 17:24 (external edit)