Should mirabegron (Myrbetriq) be held in patients with a urinary tract infection (UTI)?

Mirabegron Management During Urinary Tract Infections

Mirabegron should be continued during a urinary tract infection (UTI) as there is no evidence-based recommendation to hold this medication during active UTI treatment. The management of UTIs should focus on appropriate antimicrobial therapy while continuing medications for overactive bladder.

Rationale for Continuing Mirabegron During UTI

Evidence Assessment

• The 2024 European Association of Urology (EAU) guidelines on urological infections 1 do not list mirabegron as a medication that should be discontinued during UTI treatment
• The guidelines emphasize managing underlying urological abnormalities and complicating factors while treating the infection 1
• No specific contraindication exists for mirabegron use during UTI treatment in available evidence

Mechanism of Action Considerations

• Mirabegron is a β3-adrenoceptor agonist that works by enhancing bladder storage function and relaxing the urinary bladder 2
• Unlike antimuscarinic agents, mirabegron does not affect detrusor contractility in a way that would impair bladder emptying, which is important during UTI treatment

UTI Management Algorithm While on Mirabegron

1. Confirm UTI diagnosis

   • Presence of urinary symptoms (dysuria, frequency, urgency)
   • Obtain urine culture before initiating antimicrobial therapy 1
   • Distinguish UTI symptoms from baseline OAB symptoms

2. Initiate appropriate antimicrobial therapy

   • Select empiric therapy based on local resistance patterns 1
   • For uncomplicated UTI: oral therapy is typically sufficient
   • For complicated UTI: consider parenteral therapy initially 1
   • Adjust based on culture results when available

3. Continue mirabegron therapy

   • Maintain regular dosing of mirabegron throughout UTI treatment
   • Monitor for any worsening of urinary symptoms

4. Special considerations

   • For catheter-associated UTI: replace or remove indwelling catheter before starting antimicrobial therapy 1
   • For patients with severe symptoms: ensure adequate hydration and symptom management

Potential Pitfalls and Caveats

1. Symptom overlap

   • UTI symptoms may overlap with OAB symptoms, making assessment of treatment response challenging
   • Focus on systemic symptoms (fever, flank pain) to evaluate UTI resolution

2. Drug interactions

   • Be aware that mirabegron interacts with many drugs via cytochrome P450 isoenzymes 3
   • Review potential interactions with selected antimicrobial agents

3. Monitoring considerations

   • Monitor blood pressure as mirabegron can cause dose-dependent increases 3
   • Ensure complete resolution of UTI symptoms distinct from baseline OAB symptoms

Conclusion for Clinical Practice

Mirabegron therapy should be continued during UTI treatment. The focus should be on appropriate antimicrobial therapy for the UTI while maintaining the patient's established OAB management. This approach minimizes disruption to bladder function control while effectively treating the infection. After UTI resolution, reassess OAB symptoms to determine if any adjustments to mirabegron therapy are needed.