Mirabegron for overactive bladder

NICE state that (1)

• "..Mirabegron is recommended as an option for treating the symptoms of overactive bladder only for people in whom antimuscarinic drugs are contraindicated or clinically ineffective, or have unacceptable side effects.."

Mirabegron:

• has a marketing authorisation in the UK for the 'symptomatic treatment of urgency, increased micturition frequency and/or urgency incontinence as may occur in patients with overactive bladder (OAB)'
• is a beta-3-adrenoceptor agonist
  • activates beta-3-adrenoceptors causing the bladder to relax, which helps it to fill and also to store urine
• is administered orally
• summary of product characteristics lists the following possible adverse reactions for mirabegron:
  • urinary tract infection,
  • tachycardia,
  • vaginal infection,
  • cystitis, palpitation,
  • atrial fibrillation,
  • dyspepsia,
  • gastritis,
  • urticaria,
  • rash,
  • rash macular,
  • rash papular,
  • pruritus,
  • joint swelling,
  • vulvovaginal pruritis,
  • increased blood pressure,
  • increased gamma-glutamyl transpeptidase,
  • increased aspartate aminotransferase,
  • increased alanine aminotransferase,
  • eyelid oedema,
  • lip oedema,
  • leukocytoclastic vasculitis and purpura (rash)
  • for full details of adverse reactions and contraindications, see the summary of product characteristics

Mirabegron is now contraindicated in patients with severe uncontrolled hypertension; advice about regular monitoring is being introduced because of cases of severe hypertension (2).

• Mirabegron is contraindicated in patients with severe uncontrolled hypertension (systolic blood pressure =180 mm Hg or diastolic blood pressure =110 mm Hg, or both)
• blood pressure should be measured before starting treatment and monitored regularly during treatment, especially in patients with hypertension

Reference:

• 1) NICE (June 2013). Mirabegron for treating symptoms of overactive bladder
• 2) Drug Safety Update (October 14th 2015). Mirabegron (Betmiga): risk of severe hypertension and associated cerebrovascular and cardiac events