What is the role of Mirabegron (beta-3 adrenergic agonist) in treating urinary tract infections (UTIs)?

Mirabegron Has No Role in Treating Urinary Tract Infections

Mirabegron is a beta-3 adrenergic agonist approved exclusively for overactive bladder syndrome and has no therapeutic role in the treatment or prevention of urinary tract infections. 1, 2

Mechanism and Indication

• Mirabegron works by relaxing the detrusor muscle of the bladder through beta-3 adrenoceptor agonism, which enhances bladder storage capacity and reduces urgency symptoms. 1
• The drug is FDA-approved only for urgency, urinary frequency, and urge urinary incontinence associated with overactive bladder—not for infectious processes. 1
• No major urological guidelines (AUA/CUA/SUFU, European Association of Urology) mention mirabegron in the context of UTI treatment or prevention. 3

Why This Distinction Matters Clinically

Overactive bladder symptoms can mimic UTI symptoms, creating a critical diagnostic pitfall. Both conditions present with urgency, frequency, and sometimes incontinence, but they require fundamentally different treatments. 3

• Acute-onset dysuria is the hallmark symptom that distinguishes UTI from overactive bladder, with >90% accuracy for UTI when present without vaginal symptoms. 3
• Clinicians must document positive urine cultures with symptomatic episodes to diagnose recurrent UTI—symptoms alone are insufficient. 3
• Treating presumed UTI symptoms with antibiotics when the actual diagnosis is overactive bladder contributes to antimicrobial resistance and exposes patients to unnecessary adverse effects. 3

Appropriate UTI Treatment

For actual urinary tract infections, first-line therapy includes nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin for 3-7 days, depending on local resistance patterns. 3

• Fluoroquinolones should be avoided for uncomplicated UTI due to unfavorable risk-benefit ratios and collateral damage to normal flora. 3
• Asymptomatic bacteriuria should not be treated in non-pregnant women, as treatment increases the risk of symptomatic infection and resistance. 3

Mirabegron Safety Concerns

While mirabegron is not used for UTI, clinicians should be aware that urinary tract infections are actually listed as a common adverse effect of mirabegron therapy (occurring in clinical trials). 4, 5, 2

• Other notable adverse effects include hypertension, tachycardia, and cardiovascular events requiring monitoring. 4, 2
• The persistence rate of mirabegron monotherapy is only 39.4% at 12 months, indicating many patients discontinue therapy. 6