Epinephrine (Adrenaline)

Epinephrine, also called adrenaline, is an endogenous catecholamine with potent alpha- and beta-adrenergic activity. It is a central emergency drug for anaphylaxis and cardiopulmonary resuscitation in veterinary patients. Continuous infusion has an additional role in selected severe circulatory failures where combined vasopressor and cardiac stimulation is required.

Group

Catecholamine vasopressor

Mechanism of Action

Alpha1-receptor stimulation produces vasoconstriction, increasing vascular tone and reducing mucosal swelling. Beta1 stimulation increases myocardial contractility and heart rate, while beta2 stimulation relaxes bronchial smooth muscle and reduces mediator release from some inflammatory cells. During cardiopulmonary resuscitation, peripheral vasoconstriction helps raise aortic diastolic pressure and coronary perfusion pressure during chest compressions.

Dose Rates

Dog

Use / stage	Dose	Route	Schedule	Instructions
Cardiopulmonary resuscitation	0.01 mg/kg	IV, IO	Every 0.05–0.0833333333 h	Nonshockable arrest; current standard dose. Do not automatically escalate to the historical 0.1 mg/kg regimen.
Anaphylaxis	Reference only	IM		Source: 5–10 mcg/kg IM or IV, with repeat 5–15-minute dosing and canine total caps of 0.3 mg below 40 kg or 0.5 mg above 40 kg. Cap timing and the exact 40 kg boundary are unclear; retain as a protocol pending clarification. IV use is a distinct monitored emergency intervention.
Vasopressor infusion	0.05 mcg/kg/min	IV	Continuous

Cat

Use / stage	Dose	Route	Schedule	Instructions
Cardiopulmonary resuscitation	0.01 mg/kg	IV, IO	Every 0.05–0.0833333333 h	Nonshockable arrest; current standard dose. Do not automatically escalate to the historical 0.1 mg/kg regimen.
Anaphylaxis	Reference only	IM		Source: 5–10 mcg/kg IM or IV, with repeat 5–15-minute dosing and canine total caps of 0.3 mg below 40 kg or 0.5 mg above 40 kg. Cap timing and the exact 40 kg boundary are unclear; retain as a protocol pending clarification. IV use is a distinct monitored emergency intervention.
Vasopressor infusion	0.05 mcg/kg/min	IV	Continuous

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Anaphylaxis	20 mcg/kg	IM
Anaphylaxis	5–10 mcg/kg	IV		Monitored IV emergency use with appropriate dilution.

Pig

Use / stage	Dose	Route	Schedule	Instructions
Anaphylaxis	20 mcg/kg	IM
Anaphylaxis	5–10 mcg/kg	IV		Monitored IV emergency use with appropriate dilution.

Horse

Use / stage	Dose	Route	Schedule	Instructions
Anaphylaxis	20 mcg/kg	IM
Anaphylaxis	5–10 mcg/kg	IV		Monitored IV emergency use with appropriate dilution.

Sheep

Use / stage	Dose	Route	Schedule	Instructions
Anaphylaxis	20 mcg/kg	IM
Anaphylaxis	5–10 mcg/kg	IV		Monitored IV emergency use with appropriate dilution.

Indications

Emergency treatment of anaphylaxis and anaphylactic shock in veterinary patients.
Vasopressor support during cardiopulmonary resuscitation according to an appropriate veterinary resuscitation protocol.
Continuous vasoactive support in selected patients with refractory hypotension or severe circulatory shock.
Selected local use to support hemostasis or prolong local-anesthetic action in suitable formulations.

Contraindications

Avoid routine high-dose epinephrine during canine/feline CPR.

Interactions

Other adrenergic agonists or blockers alter response.
Incompatible with bicarbonate and alkaline or oxidizing mixtures.

Adverse effects

Hypertension, excessive vasoconstriction and ventricular arrhythmias

Toxicity

Overdose can provoke dangerous hypertension, myocardial ischemia and ventricular arrhythmias.

Preparations

Preparation	Form	Strength	Route
Epinephrine 1 mg/mL 1:1000. Verify required dilution and volume before IV/IO administration.	Injection	1 mg / mL	IM, IV, IO
Epinephrine 0.1 mg/mL 1:10,000; tenfold more dilute than 1 mg/mL.	Injection	0.1 mg / mL	IV, IO

Monitoring and Administration

Monitor ECG and perfusion. For nonshockable arrest, use standard-dose epinephrine every 3–5 minutes within the full CPR protocol; in shockable arrest, prioritize initial defibrillation.

Clearly distinguish 1 mg/mL from 0.1 mg/mL. Avoid SC administration in emergencies because vasoconstriction delays absorption.

Discard oxidized brown solution. Endotracheal administration requires a distinct resuscitation protocol and is unsupported by the route schema.

Avoid concentration errors: 1:1,000 is 1 mg/mL and 1:10,000 is 0.1 mg/mL. Adding 9 mL sterile normal saline to 1 mL of 1 mg/mL solution produces 0.1 mg/mL.