Mirabegrón Cinfamed (Mirabegron)

Mirabegrón is a β3‑adrenergic receptor agonist used in the management of lower urinary tract disorders.

• Overactive bladder: increases bladder capacity and reduces the frequency of urgency episodes.
• Urinary urgency: lessens the sudden, compelling need to void.
• Urge urinary incontinence: decreases involuntary leakage associated with urgency.

• Mirabegrón selectively stimulates β3‑adrenergic receptors located on detrusor smooth muscle. Activation of these receptors raises intracellular cyclic AMP, leading to relaxation of the detrusor muscle during the storage phase of the bladder cycle. This relaxation expands functional bladder capacity, thereby diminishing urgency and episodes of urge incontinence.

Adverse reactions may occur with mirabegron therapy.

Common Side Effects

• Hypertension: elevated blood pressure observed in some patients.
• Nasopharyngitis: mild upper respiratory tract infection symptoms.
• Headache: transient cranial pain.
• Constipation: reduced bowel motility.
• Dry mouth: decreased salivation.
• Urinary retention: difficulty initiating or maintaining urine flow.

Serious or Rare Side Effects

• Severe hypertension: marked increase in blood pressure requiring medical attention.
• Tachycardia: rapid heart rate that may be symptomatic.
• Angioedema: swelling of face, lips, or airway.
• Acute urinary retention leading to bladder overdistension.
• Allergic reactions: rash, pruritus, or anaphylaxis.
• QT interval prolongation: potential cardiac conduction abnormality.

Before initiating mirabegron, clinicians should consider several safety factors.

• Monitor blood pressure: check baseline and periodic readings.
• Assess renal function: dose adjustment may be needed in severe impairment.
• Evaluate hepatic function: caution in moderate to severe liver disease.
• Review concomitant antihypertensives: risk of additive blood‑pressure effects.
• Caution in narrow‑angle glaucoma: may exacerbate intra‑ocular pressure.
• Store at room temperature: keep in the original container, protect from moisture.

Mirabegrón can interact with other medicines through metabolic pathways and pharmacodynamic effects.

Major Interactions (Avoid)

• Strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine): may increase mirabegron exposure.
• Potent CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): can raise plasma concentrations.
• Combined antimuscarinic therapy: heightened risk of urinary retention.

Moderate Interactions (Monitor Closely):\n- CYP2D6 substrates (e.g., metoprolol): may require dose adjustment.

• CYP3A4 substrates (e.g., midazolam): monitor for enhanced effects.
• Antihypertensive agents: possible additive hypotensive effect.