Isoprenalina Macure (Isoprenaline Hydrochloride)

Isoprenaline is used in cardiovascular and respiratory conditions where β‑adrenergic stimulation is required.

• Bradycardia: increases sinus rate and improves cardiac output in patients with abnormally slow heart rhythms.
• Heart block: enhances atrioventricular conduction by stimulating β1 receptors, helping restore regular rhythm.
• Cardiac arrest (adjunct): provides temporary chronotropic support during resuscitation efforts.
• Asthma: relaxes bronchial smooth muscle to relieve airway obstruction and improve breathing.
• Bronchospasm: produces bronchodilation that facilitates ventilation in acute bronchospastic episodes.

• Isoprenaline binds to both β1 and β2 adrenergic receptors, activating adenylate cyclase and raising intracellular cyclic AMP levels. The rise in cAMP enhances calcium influx in cardiac myocytes, producing positive chronotropic and inotropic effects, while in bronchial smooth muscle it promotes relaxation, leading to bronchodilation.

Isoprenaline may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Tachycardia: rapid increase in heart rate.
• Palpitations: sensation of irregular or forceful heartbeats.
• Tremor: fine muscle shaking, especially in the hands.
• Headache: mild to moderate cranial discomfort.
• Nausea: occasional stomach upset or queasiness.
• Anxiety: feelings of nervousness or restlessness.

Serious or Rare Side Effects

• Life‑threatening arrhythmias: ventricular tachycardia or fibrillation.
• Myocardial ischemia: chest pain due to reduced coronary blood flow.
• Severe hypotension or hypertension: abrupt drops or spikes in blood pressure.
• Pulmonary edema: fluid accumulation in the lungs.
• Anaphylactic reaction: severe allergic response with airway compromise.
• Hyperglycemia: marked increase in blood glucose levels.

Careful assessment and monitoring are required when administering Isoprenaline.

• Cardiovascular monitoring: continuously observe heart rate, rhythm, and blood pressure during infusion.
• Contraindications: avoid use in patients with uncontrolled tachyarrhythmias or severe coronary artery disease.
• Drug interactions: review concomitant beta‑blocker therapy, which may blunt therapeutic effect.
• Pregnancy and lactation: use only if potential benefit justifies potential risk, as safety data are limited.
• Storage: Store at 2‑8 °C: keep refrigerated, protect from light, do not freeze or shake.

Isoprenaline can interact with several drug classes, requiring vigilance.

Major Interactions (Avoid)

• Beta‑blockers: antagonize β‑adrenergic effects, potentially causing severe bradycardia.
• Monoamine oxidase inhibitors (MAOIs): may precipitate hypertensive crises when combined.
• Tricyclic antidepressants: increase risk of arrhythmias and excessive sympathetic stimulation.

Moderate Interactions (Monitor Closely)

• Digoxin: additive positive inotropic effect may predispose to toxicity.
• Calcium channel blockers: may enhance hypotensive response.
• Sympathomimetic agents (e.g., epinephrine): combined use can cause marked tachycardia or hypertension.