What are the treatment options for overactive bladder, including medication dosages?

Treatment for Overactive Bladder with Dosages

Start all patients with behavioral therapies immediately, then add beta-3 agonists (mirabegron 25-50 mg daily) as the preferred pharmacologic option over antimuscarinics due to lower cognitive risk, reserving antimuscarinics as alternatives when beta-3 agonists fail or are contraindicated. 1, 2, 3

First-Line Treatment: Behavioral Therapies (Start Immediately)

Behavioral interventions must be offered to every patient with overactive bladder before or alongside medications, as they are equally effective to antimuscarinics but carry zero risk 1:

• Bladder training and delayed voiding - patients practice postponing urination when urgency occurs, gradually extending intervals between voids 1
• Fluid management - reduce total daily fluid intake by 25% (shown to decrease frequency and urgency), with particular attention to evening fluid restriction 1, 2
• Caffeine and alcohol avoidance - eliminate bladder irritants from diet 1, 3
• Pelvic floor muscle training - strengthening exercises for urge suppression and improved bladder control 1, 2
• Weight loss - even 8% weight reduction in obese patients reduces urgency incontinence episodes by 42% 1

These therapies require 8-12 weeks to assess efficacy 2, 3.

Second-Line Treatment: Pharmacologic Options

Preferred: Beta-3 Adrenergic Agonist

Mirabegron is the first-choice medication due to significantly lower cognitive impairment risk compared to antimuscarinics 2, 3:

• Mirabegron (Myrbetriq): Start 25 mg once daily, may increase to 50 mg once daily after 4-8 weeks 4
• Effective within 4 weeks at 50 mg dose, 8 weeks at 25 mg dose 4
• Reduces incontinence episodes by 0.34-0.42 episodes per 24 hours versus placebo 4
• Reduces micturitions by 0.42-0.61 voids per 24 hours versus placebo 4
• Increases voided volume by 11-12 mL per micturition 4

Alternative: Antimuscarinic Medications

Use antimuscarinics only when beta-3 agonists fail, are contraindicated, or unavailable 1. No single antimuscarinic shows superior efficacy over others 1:

• Darifenacin (dosage not specified in guidelines, but typically 7.5-15 mg daily) 1
• Fesoterodine (dosage not specified in guidelines, but typically 4-8 mg daily) 1
• Oxybutynin - transdermal preparations preferred if dry mouth is a concern 1
• Solifenacin (dosage not specified in guidelines, but typically 5-10 mg daily) 1
• Tolterodine (dosage not specified in guidelines, but typically 2-4 mg daily) 1
• Trospium (dosage not specified in guidelines, but typically 20 mg twice daily or 60 mg extended-release daily) 1

Critical antimuscarinic contraindications and precautions 1:

• Absolute contraindication: narrow-angle glaucoma (unless ophthalmologist approves) 1
• Extreme caution required: impaired gastric emptying, history of urinary retention, post-void residual >250-300 mL 1, 3
• Avoid in patients taking solid oral potassium chloride (increased potassium absorption risk) 1
• Use cautiously in elderly and patients at risk for cognitive impairment 2

Combination Therapy

• Behavioral therapies may be combined with any pharmacologic agent for enhanced effectiveness 1, 3
• Simultaneous initiation of behavioral and drug therapy improves outcomes in frequency, voided volume, and symptom distress 3
• If monotherapy fails, consider combining antimuscarinic with beta-3 agonist 2

Treatment Adjustments for Inadequate Response

Allow 8-12 weeks to assess efficacy before changing therapy 2, 3. If inadequate symptom control or intolerable side effects occur 3:

1. Dose modification of current medication 3
2. Switch to different antimuscarinic if on antimuscarinic 3
3. Switch to beta-3 agonist if on antimuscarinic 3
4. Add combination therapy (antimuscarinic + beta-3 agonist) 2

Third-Line Treatment (Referral to Specialist)

For patients refractory to behavioral and pharmacologic therapy after adequate trials 1, 2:

• Intradetrusor onabotulinumtoxinA 100 units - requires patient ability and willingness to perform clean intermittent self-catheterization if urinary retention develops 2, 3
• Percutaneous tibial nerve stimulation (PTNS) - requires frequent office visits 3
• Sacral neuromodulation (SNS) 3

Incontinence Management Strategies (Adjunctive)

While treating the underlying condition, discuss symptomatic management 1, 3:

• Absorbent products (pads, liners, absorbent underwear) 1, 3
• Barrier creams for skin protection 1, 3
• External collection devices 3

These do not treat overactive bladder but reduce adverse consequences of incontinence 1.

Essential Monitoring

• Measure post-void residual before starting antimuscarinics in patients with emptying symptoms, history of retention, enlarged prostate, neurologic disorders, prior incontinence/prostate surgery, or long-standing diabetes 1
• Annual follow-up to assess treatment efficacy and symptom changes 2
• More frequent monitoring if using third-line therapies 2