Mirabegron Stada Arzneimittel Ag (Mirabegron)

Mirabegron acts on the β3‑adrenergic pathway to relieve symptoms of overactive bladder.

• Overactive bladder: reduces urgency episodes and increases bladder capacity.
• Urinary urgency: lessens the sudden need to void.
• Urinary frequency: decreases the number of daytime voids.

• Mirabegron selectively binds to β3‑adrenergic receptors located in the detrusor smooth muscle of the urinary bladder. Activation of these receptors stimulates cyclic adenosine monophosphate (cAMP) production, leading to relaxation of the detrusor muscle during the storage phase. This relaxation increases functional bladder capacity and reduces involuntary contractions, thereby alleviating symptoms of urgency, frequency, and urge incontinence. The effect is dose‑dependent and does not involve muscarinic pathways.

Mirabegron may be associated with several adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Hypertension: mild to moderate increase in blood pressure.
• Headache: transient cranial discomfort.
• Nasopharyngitis: inflammation of the nasal passages and throat.
• Constipation: reduced bowel movements.
• Dry mouth: decreased salivation.
• Dizziness: sensation of lightheadedness.

Serious or Rare Side Effects

• Angioedema: rapid swelling of face, lips, or airway.
• Severe hypertension: marked elevation of blood pressure requiring medical intervention.
• Urinary retention: difficulty emptying the bladder that may lead to infection.
• Tachycardia: elevated heart rate that may be symptomatic.

Before initiating therapy, clinicians should evaluate patient-specific risk factors and monitor for adverse events.

• Blood pressure monitoring: check baseline and periodically during therapy.
• Urinary retention assessment: evaluate for difficulty voiding before and during treatment.
• Concomitant antihypertensive review: adjust doses if blood pressure rises.
• Hepatic impairment caution: use with care in patients with severe liver dysfunction.
• Pregnancy and lactation: avoid use unless benefits outweigh potential risks.
• Store at room temperature: keep in original packaging, protect from moisture and light.

Mirabegron can interact with several medicines; understanding the interaction potential helps optimize therapy.

Major Interactions (Avoid)

• Strong CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): may increase mirabegron exposure.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): can raise plasma levels.
• Anticholinergic agents: may exacerbate urinary retention.

Moderate Interactions (Monitor Closely)

• Metoprolol: mirabegron can increase its concentration, requiring dose adjustment.
• Digoxin: potential increase in serum levels, monitor therapeutic range.
• Antihypertensive drugs: mirabegron may reduce their efficacy, observe blood pressure.