What is the recommended treatment and dosage for overactive bladder using Mirabegron (beta-3 adrenergic agonist)?

From the Guidelines

Mirabegron is recommended as a first-line treatment for overactive bladder at an initial dose of 25 mg once daily, which can be increased to 50 mg once daily if needed after about 8 weeks based on individual response. The medication should be taken with water and can be administered with or without food. Patients with severe renal impairment (eGFR 15-29 mL/min) or moderate hepatic impairment should not exceed 25 mg daily, while those with end-stage renal disease or severe hepatic impairment should avoid mirabegron altogether, as stated in the 2023 European Association of Urology guidelines 1. The drug works by activating beta-3 adrenergic receptors in the bladder, causing detrusor muscle relaxation during the storage phase, which increases bladder capacity and reduces urinary frequency and urgency.

Common side effects include hypertension, headache, and urinary tract infections, as reported in several randomized controlled trials 1. Blood pressure should be monitored regularly, especially at treatment initiation, as mirabegron is contraindicated in patients with uncontrolled hypertension (≥180/110 mmHg) 1. Full therapeutic effects may take 8-12 weeks to develop, so patients should continue treatment even if immediate benefits aren't apparent. The American Urological Association (AUA) and the Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction (SUFU) also recommend offering beta-3 agonists, such as mirabegron, to patients with overactive bladder to improve urinary urgency, frequency, and/or urgency urinary incontinence, with a strong recommendation and evidence level of Grade A 1.

Key considerations for mirabegron treatment include:

• Initial dose: 25 mg once daily
• Dose increase: up to 50 mg once daily after 8 weeks if needed
• Contraindications: uncontrolled hypertension (≥180/110 mmHg), severe renal impairment, and moderate to severe hepatic impairment
• Common side effects: hypertension, headache, and urinary tract infections
• Monitoring: regular blood pressure checks, especially at treatment initiation.

From the FDA Drug Label

In three, 12-week, double-blind, placebo-controlled, safety and efficacy studies (Studies 1,2, and 3) in patients with OAB receiving mirabegron 25 mg, 50 mg, or 100 mg (two times the maximum recommended dose) once daily, mean increases in SBP/DBP compared to placebo of approximately 0. 5 – 1 mm Hg were observed.

The recommended treatment and dosage for overactive bladder using Mirabegron is 25 mg or 50 mg once daily.

• The 50 mg dose is the maximum approved dosage.
• Mirabegron should be administered with caution to patients with clinically significant BOO 2.
• The dosage of 100 mg is two times the maximum recommended dose and was used in clinical studies to assess safety and efficacy.

From the Research

Recommended Treatment and Dosage for Overactive Bladder using Mirabegron

• Mirabegron is a beta-3 adrenergic agonist that has been shown to be effective in treating symptoms of overactive bladder (OAB) 3, 4, 5, 6, 7.
• The recommended dosage of mirabegron for OAB is 25-50 mg once daily 3, 4, 7.
• Studies have demonstrated that mirabegron at daily doses of 25,50, and 100 mg is effective in reducing symptoms of OAB, including micturition frequency, urgency incontinence, and urgency 3, 4.
• Mirabegron has been shown to be well tolerated, with common adverse events including hypertension, nasopharyngitis, and urinary tract infection 3, 6.
• The efficacy and safety of mirabegron have been evaluated in various patient populations, including those with inadequate response to initial solifenacin monotherapy 5 and in patients of different age groups and sexes 6.

Efficacy of Mirabegron in Overactive Bladder

• Mirabegron has been shown to significantly improve symptoms of OAB, including:
  • Reduction in micturition frequency 3, 4, 5, 6
  • Reduction in urgency incontinence 3, 4, 5, 6
  • Reduction in urgency 3, 4, 6
  • Improvement in quality of life measures 3, 4, 6
• Mirabegron has been compared to other treatments for OAB, including solifenacin and tolterodine, and has been shown to be effective and well tolerated 5, 6.

Safety and Tolerability of Mirabegron

• Mirabegron has been shown to be well tolerated, with a safety profile similar to that of placebo 3, 6.
• Common adverse events associated with mirabegron include:
  • Hypertension 3, 6
  • Nasopharyngitis 3, 6
  • Urinary tract infection 3, 6
• Mirabegron has been evaluated in various patient populations, including those with comorbidities and concomitant medications, and has been shown to be safe and effective in these populations 6.