Epinephrine – Life-Saving Adrenergic Agent

 

Epinephrine (adrenaline) is a powerful emergency drug used in cardiac arrest, anaphylaxis, and asthma. Learn its uses, mechanism, dosage, side effects, contraindications, brand names, and price.

Table of Contents: 

- Introduction  

- Mechanism of Action  

- Pharmacokinetics & Dynamics  

- Indications & Drug of Choice  

- Contraindications  

- Side Effects  

- Drug Interactions  

- Dosage  

- Brand Names  

- Price  

- Conclusion  

Introduction: 

*Epinephrine*, commonly known as *adrenaline*, is a vital emergency medication used to treat *cardiac arrest*, *anaphylaxis*, *acute asthma*, and other critical conditions. Its rapid action on adrenergic receptors makes it life-saving in emergencies.

Mechanism of Action:

Epinephrine stimulates *alpha-1*, *beta-1*, and *beta-2* adrenergic receptors:

- *Alpha-1:* Vasoconstriction → Increases BP  

- *Beta-1:* Increases heart rate & contractility

- *Beta-2:* Bronchodilation → Relieves airway obstruction

Pharmacokinetics & Dynamics:

- *Onset:* <1 minute (IV), 5–10 min (IM)  

- *Peak Effect:* 10 min  

- *Duration:* 10–20 minutes  

- *Metabolism:* Liver via MAO/COMT  

- *Excretion:* Urine

Indications & Drug of Choice:

- Cardiac Arrest  

- Anaphylactic Shock  

- Severe Asthma  

- Hypotension due to shock  

- Croup (nebulized)

Drug of Choice for:

- Anaphylaxis  

- ACLS cardiac arrest protocol  

- Severe bronchospasm

Contraindications:

(No absolute contraindication in life-threatening emergencies)

*Relative:*

- Hypertension  

- Hyperthyroidism  

- Glaucoma  

- Cardiac arrhythmias

Side Effects:

- Palpitations  

- Headache  

- Tremors  

- Anxiety  

- Tachycardia  

- Hypertension  

- Arrhythmias  

- Tissue necrosis (if IV extravasation occurs)

Drug Interactions:

- *Beta-blockers:* Reduce effect, may increase BP  

- *MAOIs & TCAs:* Potentiate response  

- *Digoxin:* ↑ risk of arrhythmias  

- *Diuretics:* Electrolyte imbalance increases toxicity

Dosage:

- *Anaphylaxis (IM):* 0.3–0.5 mg IM q5–15 min  

- *Cardiac Arrest (IV):* 1 mg every 3–5 minutes  

- *Nebulized (Croup):* 0.5 mL racemic in saline  

- *Auto-injector:* 0.3 mg (adult), 0.15 mg (peds)

Brand Names:

- *EpiPen*

- *Adrenalin*  

- *Auvi-Q*  

- *Primatene Mist*  

- *Symjepi*

Price:

- *USA:* $100–300 per auto-injector  

- *India/Pakistan:* Rs. 150–400 per vial

Conclusion:

Epinephrine is a cornerstone of emergency medicine. Its rapid action on cardiovascular and respiratory systems makes it essential in saving lives. While it carries potential side effects, its timely use is critical in emergencies.