Mirabegron Zentiva (Mirabegron)

Mirabegron is used in the management of overactive bladder and related lower urinary tract symptoms.

• Overactive bladder: reduces urgency episodes and increases functional bladder capacity.
• Urinary urgency: lessens the sudden need to void.
• Urinary frequency: decreases the number of daily voids.
• Urge urinary incontinence: lowers the incidence of involuntary leakage.

• Mirabegron selectively stimulates β3‑adrenergic receptors located in the detrusor smooth muscle of the bladder. Activation of these receptors increases intracellular cyclic adenosine monophosphate (cAMP), leading to relaxation of the detrusor muscle during the storage phase. This relaxation expands bladder capacity and diminishes involuntary contractions, thereby reducing urgency, frequency and urge incontinence. The drug does not act on cholinergic pathways, allowing it to be combined with antimuscarinic agents when needed.

Mirabegron may cause a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Hypertension: mild to moderate increase in blood pressure.
• Nasopharyngitis: inflammation of the nasal passages and throat.
• Urinary tract infection: symptoms of dysuria or frequency.
• Headache: mild to moderate intensity.
• Constipation: reduced bowel movements.
• Dry mouth: decreased salivation.

Serious or Rare Side Effects

• Urinary retention: difficulty emptying the bladder.
• Severe hypertension: marked elevation of blood pressure requiring medical attention.
• Angioedema: swelling of face, lips or throat that may compromise airway.
• Myocardial infarction: rare occurrence of heart attack.
• Anaphylaxis: severe allergic reaction with systemic symptoms.

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

• Cardiovascular assessment: review baseline blood pressure and heart disease history.
• Blood pressure monitoring: check regularly during treatment.
• Renal function: use caution in severe renal impairment.
• Uncontrolled hypertension: avoid use until blood pressure is controlled.
• Concomitant CYP2D6 substrates: assess for potential drug‑level changes.
• Store at ambient temperature: keep in the original pack, protect from moisture.

Mirabegron can interact with several medication classes; awareness of these interactions helps optimize therapy.

Major Interactions (Avoid)

• Strong CYP2D6 inhibitors: may raise mirabegron levels, increasing hypertension risk.
• Anticholinergic bladder agents: may diminish mirabegron efficacy.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents: mirabegron may reduce their blood‑pressure‑lowering effect.
• Digoxin: plasma concentrations may increase, requiring monitoring.
• CYP3A4 inhibitors or inducers: may modestly alter mirabegron exposure.