Adrenaline

Epinephrine

Mechanism :

Epinephrine is an adrenergic (sympathomimetic) agent and cardiac stimulant. It belongs to the group of endogenous compounds known as catecholamines. The actions of epinephrine resemble the effects of stimulation of adrenergic nerves. It acts on both alpha and beta receptor sites of sympathetic effector cells. Its most prominent actions are on the beta receptors of the smooth muscles of the heart and blood vessels.

Indication :

• Anaphylaxis
• Acute asthmatic attack
• Asystole/Pulseless arrest
• Symptomatic bradycardia
• Croup

Contraindications :

Epinephrine is contraindicated in patients with known hypersensitivity to sympathomimetic amines, angle closure glaucoma, and in nonanaphylactic shock. It should not be used together with anaesthetic agents such as cyclopropane or halothane as these may sensitize the heart to arrhythmic action of sympathomimetic drugs.

Epinephrine should not ordinarily be used in those cases where vasopressor drugs may be contraindicated, e.g., in thyrotoxicosis, diabetes, in obstetrics when maternal blood pressure is in excess of 130/80 and in hypertension and other cardiovascular disorders.

Dosing :

Acute attack of asthma:

0-20 kg: 0.25 ml in 2 ml of normal saline via a nebulizer.

20-40 kg: 0.5 ml in 2 ml of normal saline via a nebulizer.

>40 kg: 0.75 in 2 ml of normal saline via a nebulizer.

Anaphylaxis: (give 1: 1000 solution)

In <30 kg: 0.01 mg/kg or 0.01 ml/kg given by SC or IM; doses to not exceed 0.3 mg/injection.

In >30 kg: 0.3-0.5 mg given by SC or IM; doses to not exceed 0.5 mg/injection.

In both the cases, repeat every 5-10 mins if necessary.

Asystole/Pulseless Arrest (off-label): (give 1: 10,000 solution)

0.01 mg/kg IV with a maximum dose of 1 mg; repeat every 3-5 min until spontaneous circulation returns.

0.1 mg/kg (0.1 ml/kg of 1: 1000 solution; 1 mg/ml) endotracheal; dose to not exceed 2.5 mg every 3-5 min until IV access has been established or spontaneous circulation ensues. Immediately after administration, flush with 5 ml of normal saline.

Symptomatic bradycardia (off-label):

1: 10,000 solution: 0.01 mg/kg IV every 3-5 mins; dose to not exceed 1 mg.

1: 1000 solution: 0.1 mg/kg (0.1 ml/kg) endotracheal every 3-5 mins if necessary; each dose to be flushed by at least 5 ml of sodium chloride solution.

Neonates (<28 days): 0.01-0.03 mg/kg IV of 1: 10,000 solution every 3-5 mins; higher dose not to be given.

Neonates (IV access not available): 0.05-0.1 mg/kg endotracheal tube of 1: 10,000 solution; each dose to be followed by at least 5 ml of sodium chloride solution; lower doses are not effective.

Adverse Effect :

Anxiety, headache, fear, palpitations, cardiac arrhythmias, hypertension, hemorrhage, hemiplegia, subarachnoid hemorrhage, anginal pain, throbbing headache, tremor, weakness, flushing, dizziness, pallor and respiratory difficulty.

Interaction :

Beta-blockers: Severe hypertension.
Volatile anaesthetics: Arrhythmia.
Spironolactone: May diminish the vasoconstricting effect of Alpha-/Beta-Agonists.
Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics.
Tricyclic Antidepressants: May enhance the vasopressor effect of Alpha-/Beta-Agonists (Direct-Acting).

Renal Dose :

Hepatic Dose :