What is the recommended dosage and patient education for Mirabegron (beta-3 adrenergic agonist) in treating overactive bladder symptoms?

Mirabegron Dosage and Patient Education for Overactive Bladder

The recommended starting dosage of mirabegron for adult patients with overactive bladder is 25 mg orally once daily, which can be increased to a maximum of 50 mg once daily after 4-8 weeks if needed. 1

Dosing Recommendations

• Initial dosage for adults with OAB is 25 mg orally once daily 1
• Dose may be increased to 50 mg once daily after 4-8 weeks if needed for better symptom control 1
• For patients with renal impairment:
  • eGFR 30-89 mL/min/1.73m²: Start with 25 mg, maximum 50 mg 1
  • eGFR 15-29 mL/min/1.73m²: Maximum dose is 25 mg 1
  • eGFR <15 mL/min/1.73m²: Not recommended 1
• For patients with hepatic impairment:
  • Child-Pugh Class A (mild): Start with 25 mg, maximum 50 mg 1
  • Child-Pugh Class B (moderate): Maximum dose is 25 mg 1
  • Child-Pugh Class C (severe): Not recommended 1

Patient Education Points

• Mirabegron should be taken once daily with or without food 1, 2
• Patients should be informed that clinical improvement may be observed as early as 4 weeks after starting treatment 2
• Regular blood pressure monitoring is recommended, especially during the initial treatment period and for patients with pre-existing hypertension 3
• For men with lower urinary tract symptoms, regular re-evaluation of symptoms and post-void residual volume is advised 3
• Patients should be instructed to discontinue medication if they experience worsening voiding symptoms or urinary stream after starting therapy 3
• Unlike antimuscarinic agents, mirabegron has a significantly lower incidence of dry mouth (2.8% vs 8.6% with tolterodine ER), making it a good option for patients who cannot tolerate anticholinergic side effects 4

Efficacy and Safety Information

• Mirabegron has demonstrated significant improvements in key OAB symptoms including:
  • Reduced micturition frequency 2, 5
  • Decreased urgency incontinence episodes 2, 5
  • Increased volume voided per micturition 2, 5
• Improvements in symptoms are typically observed as early as the first assessment at week 4 and are maintained throughout treatment 2
• Mirabegron has shown efficacy in both treatment-naïve patients and those who previously discontinued antimuscarinic therapy 2
• The most common adverse events reported with mirabegron include hypertension, nasopharyngitis, and urinary tract infection 2

Combination Therapy Considerations

• For patients with inadequate response to mirabegron 25mg monotherapy over a 6-month period, combination therapy with an antimuscarinic agent may be considered 3
• Combination therapy with mirabegron plus solifenacin has demonstrated improved efficacy without significantly affecting the safety profile compared to monotherapy 3, 6
• The SYNERGY and BESIDE trials provide strong evidence for the efficacy and safety of combination therapy using mirabegron with solifenacin 3, 7

Special Population Considerations

• Mirabegron 25mg has demonstrated safety and therapeutic efficacy in older patients with overactive bladder and multiple comorbidities 3, 8
• Cardiovascular safety analyses have shown no significant concerns with mirabegron treatment 6, 9
• For pediatric patients aged 3 years and older weighing 35 kg or more with neurogenic detrusor overactivity, mirabegron is dosed similarly to adults 1