Will Mirabegron help with bladder spasms in patients with indwelling catheters?

Management of Bladder Spasms in Patients with Indwelling Catheters: Role of Mirabegron

Summary Recommendation

Mirabegron is not recommended as a first-line treatment for bladder spasms in patients with indwelling catheters, as indwelling catheters themselves should be avoided whenever possible and removed as soon as feasible due to their association with complications.

Understanding Bladder Spasms with Indwelling Catheters

Bladder spasms are a common complication in patients with indwelling catheters, resulting from:

• Mechanical irritation of the bladder wall by the catheter
• Detrusor muscle overactivity
• Urinary tract infections
• Catheter blockage or malposition

Catheter Management as Primary Approach

The primary approach to managing bladder spasms should focus on proper catheter management:

1. Avoid indwelling catheters whenever possible 1

   • Indwelling catheters should only be used when other options are contraindicated, ineffective, or no longer desired by the patient 1
   • The AUA/SUFU guidelines strongly recommend against indwelling catheters as a management strategy for overactive bladder except as a last resort 1

2. If an indwelling catheter is necessary:

   • Remove the catheter as soon as possible (within 48 hours if feasible) 1
   • Use intermittent catheterization instead of indwelling catheters when possible 1
   • If chronic indwelling catheterization is required, suprapubic catheterization is preferred over urethral catheterization 1
   • Ensure proper catheter size and positioning
   • Maintain adequate hydration
   • Use silver alloy-coated catheters if available 1

Pharmacological Management of Bladder Spasms

When bladder spasms persist despite optimal catheter management:

1. First-line pharmacological options:

   • Antimuscarinic medications (e.g., oxybutynin, solifenacin, tolterodine)
   • These have established efficacy for overactive bladder symptoms 1

2. Role of Mirabegron:

   • Mirabegron is a β3-adrenoreceptor agonist approved for overactive bladder 2, 3

   • Efficacy considerations:

     • Shows modest efficacy in OAB (preventing approximately one episode of urinary incontinence every 2 days) 4
     • No specific studies evaluating mirabegron for catheter-associated bladder spasms
     • May be considered in patients who cannot tolerate antimuscarinic side effects 1, 3

   • Safety considerations:

     • Better tolerated than antimuscarinic drugs regarding dry mouth and constipation 2, 3
     • Can cause cardiac arrhythmias (especially tachycardia) 4
     • May cause dose-dependent increases in blood pressure 4
     • Interacts with many drugs via cytochrome P450 isoenzymes 4

3. Advanced options for refractory cases:

   • OnabotulinumtoxinA injections may be considered for patients with neurogenic bladder who are refractory to oral medications 1

Special Considerations

1. Patients with neurogenic lower urinary tract dysfunction:

   • May benefit from antimuscarinics, beta-3 agonists, or a combination 1
   • Consider onabotulinumtoxinA for refractory cases 1

2. Management of catheter-associated UTIs:

   • Do not treat asymptomatic bacteriuria in catheterized patients 1, 5
   • Only treat symptomatic UTIs with targeted antimicrobial therapy 5
   • Consider catheter change before collecting specimens if current catheter has been in place >2 weeks 5

3. Persistence of treatment:

   • Mirabegron has a persistence rate of only 39.4% at 12 months in real-world practice 6
   • Patients with more severe symptoms may require combination therapy 6

Conclusion

While mirabegron may have a role in managing bladder spasms in selected patients with indwelling catheters who cannot tolerate antimuscarinic medications, the primary approach should focus on proper catheter management and considering alternatives to indwelling catheterization. The evidence specifically for mirabegron in catheter-associated bladder spasms is limited, and its modest efficacy must be weighed against potential adverse effects, particularly cardiovascular risks.