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overactive_bladder

overactive bladders, urgency and urge incontinence

see also:

introduction

  • overactive bladder (OAB) is a troublesome condition resulting from detrusor overactivity which contracts inappropriately during bladder filling
  • it has a serious impact on quality of life
  • urinary incontinence is one of the commonest reasons for admission into a nursing home and increases risk of local skin infections and urinary tract infections (UTIs) / cystitis, while the constant smell of urine becomes a socially isolating problem
  • ~50% of nursing home residents have OAB or urinary incontinence
  • urgency increases falls risk in the elderly
  • it is more common in those with:
    • obesity - a risk factor only in women not men
    • post-menopausal oestrogen deficiency states
    • age > 75yrs due to decreased bladder capacity and changes in muscle tone
      • occurs in 20% of those over 70yrs and in 25% of those over 75yrs
    • arthritis
    • prostatism
  • Mx is aimed at treating the cause, using behavioural Rx and pharmacologic Rx to reduce detrusor contractions

clinical features

  • urinary frequency and nocturia
  • +/- urinary urgency
  • +/- urge incontinence

aetiology

neurogenic causes

non-neurogenic causes

pharmacologic Rx options

anti-M3 antimuscarinic agents

  • selective muscarinic M3 receptor antagonists were introduced onto the Australian PBS for Rx of overactive bladders in 2005 onwards
  • eg. Tolterodine tartrate, Darifenacin hydrobromide, Solifenacin succinate

beta 3 adrenergic receptor agonists

  • mirabegron was introduced into the Australian PBS in 2013
    • it is only recommended when antimuscarinic agents are C/I, ineffective or not tolerated
    • it may cause hypertension, tachycardia, atrial fibrillation (in 1%) and it may interact with other medications such as digoxin, flecainide, tricyclic antidepressants
    • not for use in pregnancy or lactation as has reproductive toxicity
    • modest efficacy with incontinence episodes reduced by ~1.5 per day
    • terminal half-life is ~50hrs

Botox

  • onabotulinumtoxinA significantly decreased the number of urinary incontinence episodes per day and improved quality of life in those with idiopathic overactive bladder not controlled by antimuscarinics
overactive_bladder.txt · Last modified: 2019/08/02 17:17 (external edit)