Formulary
Adrenaline (Epinephrine): Uses, Dosing, Side Effects and Indian Brand Names
Adrenaline is the drug of choice for anaphylaxis (IM route) and cardiac arrest (IV route). It acts on alpha and beta adrenergic receptors to produce vasoconstriction, bronchodilation, and positive cardiac inotropic/chronotropic effects.
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Adrenaline (Epinephrine): Uses, Dosing, Side Effects and Indian Brand Names
Adrenaline is the drug of choice for anaphylaxis (IM route) and cardiac arrest (IV route). It acts on alpha and beta adrenergic receptors to produce vasoconstriction, bronchodilation, and positive cardiac inotropic/chronotropic effects.
NEET PG High-Yield: Adrenaline IM is the ONLY first-line drug for anaphylaxis -- nothing else. Route is IM (anterolateral thigh), NOT SC, NOT IV for first dose. Two concentrations: 1:1000 (for IM) and 1:10,000 (for IV in cardiac arrest). In cardiac arrest, give 1 mg IV every 3-5 minutes. Adrenaline + halothane = ventricular fibrillation (sensitisation). Never use adrenaline with local anaesthetics in end-artery areas (fingers, toes, nose, ears, penis).
Clinical overview
Adrenaline (epinephrine) is the most important emergency drug in medicine and is the drug of choice for anaphylaxis, cardiac arrest, and as a vasoconstrictor additive to local anaesthetics. It is an endogenous catecholamine produced by the adrenal medulla and is the primary mediator of the fight-or-flight response. In anaphylaxis, intramuscular adrenaline is the ONLY first-line treatment and is life-saving -- no other drug can reverse all the pathophysiological features of anaphylaxis simultaneously (bronchospasm, laryngeal oedema, vasodilation, and hypotension). The anterolateral thigh (vastus lateralis) is the preferred injection site for IM adrenaline in anaphylaxis. In cardiac arrest (ACLS protocol), IV adrenaline 1 mg is given every 3-5 minutes during CPR for all cardiac arrest rhythms. Adrenaline is also added to local anaesthetic solutions (typically 1:200,000 concentration) to cause local vasoconstriction, which slows anaesthetic absorption, prolongs the duration of action, and reduces surgical bleeding. In India, adrenaline is available in all emergency departments and is included in the anaphylaxis kit. Auto-injectors (EpiPen equivalents) are expensive and less available than in Western countries, making pre-filled syringes and ampoules the standard. The drug must be stored away from light and heat and checked regularly for discolouration (should be clear; brown or pink discolouration indicates oxidation and loss of potency).
Pharmacological class
Adrenaline (Epinephrine) belongs to the Catecholamine (sympathomimetic amine; direct-acting alpha and beta adrenergic agonist) class. Adrenaline acts on both alpha and beta adrenergic receptors. Alpha-1: vasoconstriction (raises blood pressure, reduces mucosal oedema). Beta-1: positive inotropic and chronotropic effects (increases heart rate and contractility). Beta-2: bronchodilation, suppression of mediator release from mast cells, and peripheral vasodilation in skeletal muscle. The receptor effects are dose-dependent: at low doses, beta effects predominate; at higher doses, alpha-mediated vasoconstriction becomes more prominent.
Indian brand names and formulations
Available as: Adrenaline Injection IP (Various manufacturers), Adretor (Neon Laboratories), EpiPen (Mylan -- limited availability in India), Epinephrine (Generic).
Injection: 1:1000 (1 mg/mL in 1 mL ampoules -- for IM/SC), 1:10,000 (0.1 mg/mL -- prefilled syringe for IV use in cardiac arrest, or diluted from 1:1000). Auto-injector (EpiPen 0.3 mg adult, 0.15 mg junior -- limited availability in India). Nebuliser solution: racemic epinephrine (for croup). Topical: 1:1000 for haemostasis.
Regulatory status
Adrenaline (Epinephrine) is classified under Schedule H in India under the Drugs and Cosmetics Act, 1940. Schedule H prescription drug. Must be available in all emergency departments and operation theatres. Included in the WHO Model List of Essential Medicines and NLEM 2022. Auto-injectors are expensive (INR 5000-8000) and have limited availability in India.
Indications
- Anaphylaxis (FIRST-LINE -- IM injection into anterolateral thigh)
- Cardiac arrest -- all rhythms (IV 1 mg every 3-5 minutes per ACLS)
- Severe acute asthma unresponsive to nebulised bronchodilators (SC/IM)
- Vasoconstrictor additive to local anaesthetics (prolongs duration, reduces bleeding)
- Croup (nebulised racemic epinephrine)
- Upper airway obstruction (angioedema)
- Cardiogenic shock (IV infusion as vasopressor -- second-line after noradrenaline)
- Control of surgical bleeding (topical)
Dosing
Anaphylaxis (IM): Adults 0.5 mg (0.5 mL of 1:1,000), Children 0.01 mg/kg (max 0.5 mg). Inject into ANTEROLATERAL THIGH. Repeat every 5-15 minutes if needed. Cardiac arrest (IV): 1 mg (1 mL of 1:10,000 or 10 mL of 1:10,000) every 3-5 minutes. Local anaesthetic additive: 1:200,000 concentration (5 mcg/mL). Infusion (shock): 0.01-0.1 mcg/kg/min IV, titrated. CRITICAL: two concentrations exist -- 1:1000 (1 mg/mL, for IM/SC) and 1:10,000 (0.1 mg/mL, for IV). NEVER give 1:1000 IV -- fatal arrhythmia risk.
Contraindications
- Narrow-angle glaucoma (relative -- mydriasis increases intraocular pressure)
- No absolute contraindication in true anaphylaxis (benefit always outweighs risk)
- End-artery circulation areas for local anaesthetic additive (fingers, toes, ears, nose, penis -- risk of ischaemic necrosis)
- Hyperthyroidism and phaeochromocytoma (increased sensitivity to catecholamines)
- Patients on non-selective beta-blockers (may develop severe hypertension from unopposed alpha stimulation)
Adverse effects
- Tachycardia, palpitations (beta-1 stimulation)
- Hypertension (alpha-1 vasoconstriction)
- Tremor and anxiety (beta-2 stimulation, CNS effects)
- Cardiac arrhythmias (especially in patients on halothane anaesthesia -- sensitises myocardium to catecholamines)
- Myocardial ischaemia (increased oxygen demand)
- Pulmonary oedema (with IV bolus overdose)
- Tissue necrosis (if SC injection extravasates or if used in end-artery areas with local anaesthetic)
- Headache
- Hyperglycaemia (glycogenolysis and gluconeogenesis)
Drug interactions
- Non-selective beta-blockers (propranolol) -- unopposed alpha stimulation causing severe hypertension and reflex bradycardia
- Halothane anaesthesia -- sensitises the myocardium to adrenaline, risk of ventricular fibrillation
- Tricyclic antidepressants -- potentiate catecholamine effects by blocking reuptake
- MAO inhibitors -- potentiate adrenaline effects (slower metabolism)
- Cocaine -- blocks catecholamine reuptake, risk of hypertensive crisis and arrhythmias
- Ergot alkaloids -- additive vasoconstriction
Pregnancy and lactation
Category C. Adrenaline reduces uterine blood flow (alpha-mediated vasoconstriction) and can cause fetal distress. However, in anaphylaxis during pregnancy, adrenaline is absolutely indicated and life-saving -- untreated anaphylaxis has near 100% maternal and fetal mortality. The left lateral position reduces aortocaval compression during resuscitation. For elective procedures, adrenaline in local anaesthetic is used at standard concentrations without significant fetal risk.
Exam-style clinical scenario
A 25-year-old man develops urticaria, lip swelling, wheeze, and hypotension (BP 70/40 mmHg) 10 minutes after receiving IV ceftriaxone. SpO2 is 88%. What is the immediate management? Answer: This is anaphylaxis. Immediate management: (1) IM adrenaline 0.5 mg (0.5 mL of 1:1000) into the ANTEROLATERAL THIGH -- this is the FIRST drug and must be given IMMEDIATELY, (2) Call for help, position supine with legs elevated (Trendelenburg), (3) High-flow oxygen, (4) IV fluid bolus (normal saline 500-1000 mL rapidly), (5) Repeat IM adrenaline every 5-15 minutes if no improvement. Second-line: IV chlorpheniramine 10 mg, IV hydrocortisone 200 mg (prevents biphasic reaction), nebulised salbutamol for persistent wheeze. NEVER delay adrenaline for antihistamines or steroids -- they are adjuncts, not first-line.
Cost in India
INR 10-25 per ampoule (1 mg/mL, 1 mL); Auto-injector (EpiPen): INR 5000-8000 (limited availability)
Clinical governance
Author: MedNext Editorial Team. Clinical reviewer: Awaiting clinical review. Jurisdiction: India (Drugs and Cosmetics Act, 1940). Sources: CIMS India, Indian Pharmacopoeia. Publication state: Awaiting clinical review. Correction: Report errors at support@mednext.academy.
Frequently Asked Questions
Why is IM adrenaline given in the anterolateral thigh rather than the deltoid?
The anterolateral thigh (vastus lateralis) has the best blood supply of any IM injection site, providing the fastest absorption and most rapid peak plasma levels. Studies comparing IM adrenaline in the thigh vs deltoid show significantly higher and faster peak plasma concentrations from the thigh. In anaphylaxis, where every minute counts, the thigh route ensures the fastest systemic drug delivery. SC injection is avoided because absorption is slow and unpredictable (adrenaline causes local vasoconstriction at the injection site, paradoxically slowing its own absorption).
Why should IV adrenaline not be used as first-line in anaphylaxis outside cardiac arrest?
IV adrenaline bolus in a patient with a beating heart (even a hypotensive one) carries a high risk of fatal arrhythmias (ventricular tachycardia, ventricular fibrillation) and severe hypertension. IM adrenaline provides a safer, more gradual absorption profile with a lower peak concentration. IV adrenaline infusion (NOT bolus) is reserved for refractory anaphylaxis unresponsive to repeated IM doses, and should only be given by experienced clinicians with cardiac monitoring in a resuscitation setting.
What is the biphasic reaction in anaphylaxis?
A biphasic reaction is a recurrence of anaphylaxis symptoms after initial resolution, occurring 4-12 hours (up to 72 hours) after the initial episode without re-exposure to the allergen. It occurs in approximately 5-20% of anaphylaxis cases. This is why patients are observed for at least 6-12 hours after anaphylaxis (24 hours for severe presentations). IV hydrocortisone is given as an adjunct partly to reduce the risk of biphasic reactions, though evidence for its effectiveness in this role is limited.
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