Mirabegron Teva (Mirabegron)

Mirabegron is a β3‑adrenergic receptor agonist used in the management of overactive bladder symptoms.

• Overactive bladder: increases functional bladder capacity and reduces urgency and incontinence episodes.
• Urinary frequency: lowers the average number of daytime voids, helping patients achieve longer intervals between bathroom trips.
• Urgency: diminishes the sudden, compelling need to void, thereby improving quality of life for affected individuals.
• Urge urinary incontinence: reduces the frequency of involuntary urine leakage during episodes of strong urge.
• Bladder storage symptoms: enhances overall bladder storage capacity, leading to fewer nighttime awakenings for voiding.
• Quality of life: contributes to improved daily activities by minimizing disruptive urinary symptoms.

• Mirabegron selectively activates β3‑adrenergic receptors located in the detrusor smooth muscle of the bladder. Stimulation of these receptors increases cyclic AMP levels, leading to relaxation of the detrusor muscle during the storage phase. This relaxation expands bladder capacity and reduces involuntary contractions, thereby decreasing urgency, frequency and urge incontinence. The drug does not significantly affect the α‑adrenergic or muscarinic pathways, allowing it to act without the anticholinergic side‑effect profile typical of other bladder agents.

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

Common Side Effects

• Hypertension: increase in blood pressure, often mild.
• Nasopharyngitis: inflammation of the nose and throat.
• Headache: mild to moderate head pain.
• Urinary retention: difficulty initiating or maintaining urine flow.
• Dry mouth: mild reduction in salivation.
• Dizziness: transient light‑headedness.
• Constipation: decreased bowel movements.
• Back pain: mild spinal discomfort.
• Peripheral edema: swelling of lower limbs.
• Nausea: mild stomach upset.
• Fatigue: feeling of tiredness.

Serious or Rare Side Effects

• Severe hypertension: marked rise in blood pressure requiring medical attention.
• Tachycardia: rapid heart rate that may be symptomatic.
• Angioedema: swelling of face, lips, tongue or airway.

When prescribing Mirabegron, clinicians should consider several precautionary measures to ensure safe use.

• Blood pressure monitoring: check baseline and periodic readings due to risk of hypertension.
• Cardiovascular assessment: evaluate for uncontrolled hypertension or arrhythmias before initiation.
• Renal function: adjust use in patients with severe renal impairment.
• Drug interactions: review concomitant β‑agonists or anticholinergics that may affect efficacy.
• Pregnancy and lactation: avoid use unless potential benefit justifies potential risk.
• Store at ambient temperature: keep below 25 °C in original packaging, protect from moisture.

Mirabegron can affect the pharmacokinetics of several co‑administered medicines; awareness of key interactions helps optimize therapy and may require dose adjustments.

Major Interactions (Avoid)

• CYP2D6 substrates: may increase plasma levels of drugs such as metoprolol, leading to enhanced effects.
• Antihypertensives: additive blood pressure‑lowering effect when combined with agents like ACE inhibitors.

Moderate Interactions (Monitor Closely)

• Diuretics: may reduce antihypertensive efficacy of Mirabegron; monitor blood pressure.
• Anticholinergics: concurrent use may diminish overall bladder‑control benefit.
• CYP3A4 inhibitors: can raise Mirabegron concentrations; adjust dose if needed.
• Warfarin: may increase INR; monitor coagulation parameters.
• Digoxin: potential increase in serum levels; observe for toxicity.