What are the medications for overactive bladder?

Medications for Overactive Bladder

Mirabegron is the preferred pharmacological option for overactive bladder (OAB) due to its better side effect profile, particularly regarding cognitive effects, while maintaining similar efficacy for symptom control. 1, 2

First-Line Pharmacological Options

Mirabegron (Beta-3 Adrenergic Agonist)

• Starting dose: 25 mg orally once daily
• Dose adjustment: May increase to 50 mg once daily after 4-8 weeks if needed
• FDA-approved indication: Treatment of OAB in adult patients with symptoms of urge urinary incontinence, urgency, and urinary frequency 2
• Key advantages:
  • Better cognitive safety profile compared to antimuscarinics
  • Similar efficacy to antimuscarinics
  • Lower incidence of dry mouth (similar to placebo)
  • Improvements in symptoms observed as early as 4 weeks 3
• Monitoring requirements:
  • Regular blood pressure monitoring (can cause hypertension)
  • Assess for urinary retention and constipation

Antimuscarinic Agents (Second-line or alternative options)

1. Trospium chloride

   • Good option for elderly patients due to reduced blood-brain barrier penetration
   • NNH of 8 for adverse effects 1

2. Darifenacin

   • Similar discontinuation rates to placebo
   • Less cognitive effects than other antimuscarinics 1

3. Fesoterodine

   • More adverse effects than tolterodine (NNH of 11)
   • Higher discontinuation rate due to adverse effects 1

4. Oxybutynin

   • Highest risk for discontinuation due to adverse effects
   • Higher risk of cognitive impairment, particularly in elderly patients
   • Not recommended as first-line therapy, especially in older adults 1

Combination Therapy

• For patients with inadequate response to monotherapy, consider mirabegron plus solifenacin 5mg
• Improved efficacy shown in clinical trials with side effect profile similar to monotherapy 1

Special Populations

Elderly Patients

• Mirabegron is preferred due to lower risk of cognitive side effects
• If antimuscarinics are used, consider trospium or darifenacin
• Take mirabegron with food to reduce exposure-related risks 1

Patients with Renal Impairment

• For severe renal impairment (eGFR 15-29 mL/min/1.73 m²), mirabegron should not exceed 25 mg daily 1

Advanced Treatment Options for Refractory OAB

Intradetrusor OnabotulinumtoxinA Injections

• Consider for patients who do not respond to oral medications
• FDA-approved for OAB 4
• Caution: Risk of urinary retention; patient must be willing and able to perform self-catheterization 1

Neuromodulation Therapies

• Peripheral tibial nerve stimulation (PTNS) for patients who do not respond to initial treatments
• Sacral neuromodulation may be considered in select cases 1

Common Pitfalls and Caveats

1. Antimuscarinic side effects: Dry mouth, constipation, blurred vision, and cognitive impairment are common reasons for discontinuation
2. Mirabegron contraindications: Severe uncontrolled hypertension, severe hepatic impairment, end-stage renal disease
3. Treatment assessment: Evaluate response after 4-8 weeks to determine efficacy
4. Cognitive monitoring: Consider periodic cognitive assessments in long-term users of anticholinergics

Treatment Algorithm

1. Start with mirabegron 25 mg daily (preferred first-line pharmacological option)
2. Assess after 4-8 weeks
   • If inadequate response: Increase to 50 mg daily
   • If still inadequate: Consider adding solifenacin 5 mg
3. If mirabegron contraindicated or not tolerated: Use trospium or darifenacin (especially in elderly)
4. For refractory cases: Consider onabotulinumtoxinA injections or neuromodulation therapies

Remember that pharmacological treatment should be accompanied by lifestyle modifications including pelvic floor muscle training, bladder training, avoiding bladder irritants, and weight loss for obese patients 1, 5.