Isoprenalina Cloridrato Monico (Isoprenaline Hydrochloride)

Isoprenaline is used in cardiovascular and respiratory conditions where stimulation of beta‑adrenergic receptors is required.

• Bradycardia: increases heart rate to restore adequate cardiac output.
• Heart block: improves atrioventricular conduction and stabilises rhythm.
• Hypotension: raises blood pressure by enhancing cardiac output.
• Asthma: relaxes bronchial smooth muscle to relieve bronchospasm.
• Bronchospasm: provides rapid bronchodilation during acute episodes.

• Isoprenaline binds to both β1 and β2 adrenergic receptors on cardiac myocytes and smooth muscle. Activation of β1 receptors increases cyclic AMP, enhancing calcium influx and resulting in increased heart rate (positive chronotropy) and contractile force (positive inotropy). Stimulation of β2 receptors on bronchial smooth muscle leads to relaxation and bronchodilation, while peripheral vasodilation contributes to a rise in cardiac output and blood pressure.

Isoprenaline may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Tremor: mild muscle tremors, especially in the hands.
• Palpitations: sensation of rapid or irregular heartbeat.
• Headache: transient headache episodes.
• Nausea: mild nausea or upset stomach.
• Anxiety: feelings of nervousness or restlessness.
• Sweating: increased perspiration.

Serious or Rare Side Effects

• Arrhythmias: potentially life‑threatening ventricular or supraventricular arrhythmias.
• Myocardial ischemia: chest pain due to increased cardiac oxygen demand.
• Severe hypotension: paradoxical drop in blood pressure requiring urgent intervention.
• Pulmonary edema: fluid accumulation in the lungs.

When using Isoprenaline, several precautions should be observed to minimize risks.

• Cardiac monitoring: continuous ECG and blood pressure monitoring during infusion.
• Dose titration: adjust dose gradually based on clinical response and hemodynamics.
• Contraindications: avoid in patients with severe tachyarrhythmias or uncontrolled hypertension.
• Drug interactions: review concomitant use of beta‑blockers and MAO inhibitors.
• Pregnancy and lactation: assess risk–benefit; use only if clearly needed.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze.

Isoprenaline can interact with several medicines, altering its efficacy or safety.

Major Interactions (Avoid)

• Beta‑blockers: antagonize beta‑adrenergic effects, reducing therapeutic response.
• MAO inhibitors: may potentiate hypertensive episodes.
• Tricyclic antidepressants: increase risk of cardiac arrhythmias.
• Non‑selective alpha agonists: unpredictable vascular responses.
• Calcium channel blockers: may increase risk of bradycardia when drug withdrawn.

Moderate Interactions (Monitor Closely)

• Digitalis glycosides: may enhance arrhythmic risk.
• Diuretics: can exacerbate electrolyte imbalances affecting cardiac function.
• Other sympathomimetics: additive tachycardia and blood pressure effects.
• Antihypertensives: may require dose adjustments.