What is the best medication for treating stress incontinence?

Best Medication for Stress Incontinence

For stress urinary incontinence in women, pelvic floor muscle training (PFMT) is the first-line treatment rather than medication, as pharmacological options have limited efficacy and significant side effects. 1

Non-Pharmacological Approaches (First-Line)

Pelvic Floor Muscle Training (PFMT)

• High-quality evidence supports PFMT as the most effective first-line treatment for stress incontinence
• Improves UI compared with no treatment (NNTB = 3) 1
• Increases continence rates significantly 1
• Risk-free and effective in 66-75% of cases 2

Combination Approaches

• PFMT combined with bladder training is particularly effective:
  • Achieves continence (NNTB = 6) 1
  • Improves UI (NNTB = 3) 1

Additional Non-Pharmacological Options

• Weight loss and exercise for obese women (moderate-quality evidence)
  • Improves UI (NNTB = 4) 1, 3
• Fluid management with 25% reduction in fluid intake 3

Pharmacological Options (Second-Line)

Duloxetine

• Only medication with some evidence for stress incontinence specifically 1, 4, 5
• Mechanism: Inhibits serotonin and norepinephrine reuptake, increasing neural input to urethral sphincter 6
• Efficacy:
  • Low-quality evidence showed reduced continence less with duloxetine than placebo 1
  • High-quality evidence showed duloxetine did not statistically significantly improve UI compared to placebo (NNTB = 13) 1
  • Reduces incontinence episodes by approximately one episode per day compared to placebo 2
• Quality of life:
  • Low-quality evidence showed improvement 1
  • Maximum gain of only 5 points on a 100-point scale 2
• Significant limitations:
  • Nausea is the most common side effect (main cause for discontinuation) 4
  • About 25% of patients discontinue due to adverse effects within 3 months 2
  • Over 40 different adverse effects reported, including suicide attempts and hepatic disorders 2

Vaginal Estrogen

• Some evidence for stress incontinence:
  • Vaginal estrogen tablets increased continence compared to placebo (NNTB = 5) 1
  • Improved UI with vaginal estrogen tablets and ovules 1
  • Most effective when combined with PFMT 1
• Note: Transdermal estrogen patches were associated with worsened UI 1

Mirabegron

• Moderate-quality evidence showed improved continence (NNTB = 12) and UI (NNTB = 9) compared to placebo 1
• However, primarily indicated for urgency incontinence rather than stress incontinence 3

Treatment Algorithm

1. Start with PFMT (with proper instruction)

   • Allow 8-12 weeks to determine efficacy 3
   • Consider adding bladder training for enhanced effect

2. For obese patients: Add weight loss program and exercise

3. If inadequate response after 8-12 weeks:

   • Consider vaginal estrogen (if postmenopausal)
   • Consider duloxetine (40mg twice daily) with careful monitoring for side effects
   • Discontinue if nausea or other side effects are intolerable

4. For severe refractory cases:

   • Consider surgical options (not covered in this response)

Important Caveats

• Duloxetine has significant side effect profile and limited efficacy
• Medication should only be considered after adequate trial of PFMT
• Vaginal estrogen may be more appropriate for postmenopausal women with concurrent vaginal atrophy
• Antimuscarinic medications (e.g., solifenacin, oxybutynin) are indicated for urgency incontinence, not stress incontinence 1, 3
• Measure post-void residual volume before initiating any pharmacologic therapy 3