What medications are used to treat overactive bladder (OAB) in women?

Medications for Treating Overactive Bladder in Women

Behavioral therapies should be used as first-line treatment for overactive bladder in women, with oral antimuscarinic medications as second-line therapy and mirabegron as an alternative second-line option for those who cannot tolerate antimuscarinic side effects. 1, 2

First-Line Treatment: Behavioral Therapies

Behavioral interventions are recommended as first-line treatment because they are as effective as antimuscarinic medications in reducing symptoms while having no adverse effects:

• Pelvic floor muscle training (PFMT) - Particularly effective for stress UI and mixed UI 1
• Bladder training and delayed voiding - Recommended for urgency UI 1
• Fluid management - 25% reduction in fluid intake can reduce frequency and urgency 1
• Weight loss - 8% weight reduction in obese women can reduce incontinence episodes by 42-47% 1

Second-Line Treatment: Pharmacologic Options

If behavioral therapies are unsuccessful, pharmacologic treatment should be initiated:

Antimuscarinic Medications (alphabetical order, no hierarchy implied):

• Darifenacin
• Fesoterodine
• Oxybutynin
• Solifenacin
• Tolterodine
• Trospium

All antimuscarinic medications have similar efficacy but differ in side effect profiles 1:

• Solifenacin has the lowest risk for discontinuation due to adverse effects 1
• Oxybutynin has the highest risk for discontinuation due to adverse effects 1
• Darifenacin and tolterodine have risks for discontinuation similar to placebo 1

Beta-3 Adrenergic Receptor Agonist:

• Mirabegron - Alternative second-line option with efficacy similar to antimuscarinics but with fewer anticholinergic side effects 2

Medication Selection Algorithm

1. For most patients: Start with an antimuscarinic medication

   • Consider solifenacin 5mg daily as first choice due to better tolerability 2
   • Generic immediate-release oxybutynin is most cost-effective option but has higher side effect profile 2

2. For elderly patients or those concerned about cognitive effects:

   • Mirabegron (starting at 25mg daily, can increase to 50mg) 2, 3
   • Trospium (lower CNS penetration, not metabolized by CYP450) 2, 4

3. For patients with narrow-angle glaucoma:

   • Avoid antimuscarinic agents unless approved by ophthalmologist 1

4. For patients with impaired gastric emptying or history of urinary retention:

   • Use antimuscarinic agents with extreme caution 1

Common Side Effects to Monitor

Antimuscarinic medications:

• Dry mouth (most common)
• Constipation
• Dry eyes
• Blurred vision
• Dyspepsia
• Urinary tract infection
• Urinary retention
• Impaired cognitive function 1

Mirabegron:

• Hypertension
• Nasopharyngitis
• Urinary tract infection 2, 3

Third-Line Treatment Options

For patients who fail behavioral and pharmacologic therapy:

• Combination therapy (mirabegron plus solifenacin 5mg) 1, 2
• Neuromodulation
• OnabotulinumtoxinA injections 1, 2

Important Considerations

• Complete symptom relief is unlikely in patients with severe baseline symptoms 1
• Regular monitoring of blood pressure is recommended with mirabegron 2
• Patients on multiple medications (≥7) have more adverse effects with antimuscarinics 2
• Patients who are refractory to behavioral and medical therapy should be evaluated by a specialist 1

Careful selection of medication based on patient characteristics, comorbidities, and potential side effects is crucial for successful management of overactive bladder in women.