Mirabegron Al (Mirabegron)

Mirabegron is indicated for conditions related to overactive bladder, a disorder of urinary storage function.

• Overactive bladder: improves bladder capacity and reduces urgency episodes.
• Urinary urgency: lessens the sudden, strong need to void.
• Urinary frequency: decreases the number of daytime voids.
• Urge urinary incontinence: reduces involuntary leakage episodes.

• Mirabegron selectively activates β3‑adrenergic receptors located on detrusor smooth muscle. Activation triggers a cascade that increases cyclic AMP, leading to relaxation of the detrusor during the bladder filling phase. This relaxation expands functional bladder capacity, thereby reducing the frequency of involuntary contractions that cause urgency and incontinence.

Adverse reactions may vary in frequency and severity.

Common Side Effects

• Hypertension: elevated blood pressure readings.
• Nasopharyngitis: mild upper‑respiratory tract infection symptoms.
• Urinary tract infection: dysuria or cloudy urine.
• Headache: mild to moderate intensity.
• Constipation: reduced bowel movements.
• Dry mouth: decreased salivation.

Serious or Rare Side Effects

• Severe hypertension: markedly high blood pressure requiring medical attention.
• Tachycardia: rapid heart rate that may be symptomatic.
• Angioedema: swelling of face, lips or throat.
• Urinary retention: difficulty initiating or maintaining urine flow.
• Allergic reactions: rash, pruritus or anaphylaxis.
• Myocardial infarction: rare cardiac event.

Before prescribing Mirabegron, clinicians should evaluate cardiovascular status and renal function.

• Blood pressure assessment: measure baseline and monitor regularly.
• Cardiovascular monitoring: watch for tachycardia or hypertension during therapy.
• Renal impairment: use caution in patients with severe renal dysfunction.
• Hepatic impairment: consider dose adjustment in moderate to severe liver disease.
• Concomitant CYP2D6 inhibitors: review other medicines that may increase mirabegron exposure.
• Store at room temperature: keep in the original pack, protect from moisture and direct sunlight.

Mirabegron can alter the pharmacokinetics of several drug classes; careful review is advised.

Major Interactions (Avoid)

• Strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine): may increase mirabegron plasma levels.
• Sympathomimetic agents (e.g., epinephrine): additive increase in blood pressure.
• Antihypertensive drugs (e.g., beta‑blockers): may reduce antihypertensive efficacy.

Moderate Interactions (Monitor Closely)

• Diuretics: monitor electrolytes and volume status.
• Anticholinergic agents: assess for additive urinary retention risk.
• Moderate CYP3A4 inhibitors (e.g., ketoconazole): may modestly raise mirabegron exposure.