Is Mirabegron (mirabegron) given in cases of urinary dribbling or retention?

Mirabegron for Urinary Dribbling vs. Retention

Mirabegron is indicated for overactive bladder with storage symptoms (urgency, frequency, urge incontinence), NOT for urinary retention or post-void dribbling. 1

Indication and Mechanism

Mirabegron is a beta-3 adrenergic agonist that relaxes the detrusor muscle during bladder filling, thereby increasing bladder storage capacity. 2, 1 The FDA-approved indications are:

• Overactive bladder (OAB) in adults with symptoms of urge urinary incontinence, urgency, and urinary frequency 1
• Neurogenic detrusor overactivity (NDO) in pediatric patients aged 3 years and older weighing 35 kg or more 1

Critical Distinction: Storage vs. Voiding Symptoms

Mirabegron treats STORAGE symptoms, not voiding symptoms. 2 This is a fundamental distinction:

• Storage symptoms (what mirabegron treats): urgency, frequency, urge incontinence, nocturia 2, 1
• Voiding symptoms (what mirabegron does NOT treat): hesitancy, weak stream, straining, incomplete emptying, post-void dribbling 2

Urinary Retention Risk

Mirabegron can actually CAUSE urinary retention in certain patients, particularly those with bladder outlet obstruction or those taking antimuscarinic medications. 1 The FDA label specifically warns:

• Administer with caution in patients with bladder outlet obstruction due to risk of urinary retention 1
• Inform patients that mirabegron may cause urinary retention in adult patients with bladder outlet obstruction 1
• Mirabegron does not significantly affect voiding urodynamic parameters, but can cause small increases in post-void residual volume 2

Clinical Application in Men with LUTS

In men with lower urinary tract symptoms, the European Association of Urology guidelines recommend: 2

• For storage symptoms (OAB component): Mirabegron 25-50 mg daily is appropriate 2
• For voiding symptoms (BOO component): Alpha-blockers or 5-alpha reductase inhibitors are indicated, NOT mirabegron 2
• Combination therapy: Mirabegron can be added to alpha-blockers (like tamsulosin) in men with both storage AND voiding symptoms 2

Common Pitfall to Avoid

Do not prescribe mirabegron for post-void dribbling or urinary retention. These are voiding symptoms that suggest bladder outlet obstruction or detrusor underactivity. 2 Mirabegron will not help and may worsen retention. 1

If a patient presents with "dribbling," clarify whether this is:

• Urge incontinence (leakage with sudden urgency) → mirabegron may help 1
• Post-void dribbling (terminal dribbling after voiding) → mirabegron is NOT indicated 2
• Overflow incontinence (from retention) → mirabegron is contraindicated 1

Monitoring Requirements

When prescribing mirabegron, monitor: 2, 1

• Blood pressure periodically, especially in hypertensive patients (mirabegron can increase BP) 2, 1
• Post-void residual volume in men with LUTS, particularly if on combination therapy 2
• Symptoms of urinary retention (advise patients to report worsening voiding symptoms) 1