Drug information of Epinephrine

Epinephrine

Drug group:

Epinephrine is a chemical that narrows blood vessels and opens airways in the lungs. These effects can reverse severe low blood pressure, wheezing, severe skin itching, hives, and other symptoms of an allergic reaction.

Mechanism of effect

Epinephrine acts on both alpha (α)- and beta (β)-adrenergic receptors. The mechanism of the rise in blood pressure is 3-fold: a direct myocardial stimulation that increases the strength of ventricular contraction (positive inotropic action), an increased heart rate (positive chronotropic action), and peripheral vasoconstriction.

Pharmacodynamic

Following intravenous administration of epinephrine, increases in systolic blood pressure and heart rate are observed. Decreases in systemic vascular resistance and diastolic blood pressure are observed at low doses of epinephrine because of β2-mediated vasodilation, but are overtaken by α1-mediated peripheral vasoconstriction at higher doses leading to increase in diastolic blood pressure.
The onset of blood pressure increase following an intravenous dose of epinephrine is < 5 minutes and the time to offset blood pressure response occurs within 20 min. Most vascular beds are constricted including renal, splanchnic, mucosal and skin.

Pharmacokinetics

When administered parenterally or intraocularly, epinephrine has a rapid onset and short duration of action.Following intravenous injection, epinephrine is rapidly cleared from the plasma with an effective half-life of < 5 min. A pharmacokinetic steady state following continuous intravenous infusion is achieved within 10-15 min.
Epinephrine is extensively metabolized with only a small amount excreted unchanged. Epinephrine is rapidly degraded to vanillylmandelic acid, an inactive metabolite, by monoamine oxidase and catechol-O-methyltransferase that are abundantly expressed in the liver, kidneys and other extraneuronal tissues.

Drug indications

Ventricular Fibrillation

Dosage

Usual Adult Dose for Asystole, Ventricular Fibrillation, Ventricular Tachycardia, Cardiac Arrest :
Injectable Solution of 0.1 mg/mL (1:10,000) :
-IV: 0.5 to 1 mg (5 to 10 mL) IV once; during resuscitation effort, 0.5 mg (5 mL) should be given IV every 5 minutes
-Intracardiac: 0.3 to 0.5 mg (3 to 5 mL) via intracardiac injection into left ventricular chamber once
-Endotracheal: 0.5 to 1 mg (5 mL to 10 mL) via endotracheal tube directly into bronchial tree once

Usual Adult Dose for Asthma – Acute :
Injectable Solution of 0.1 mg/mL (1:10,000) :
0.1 to 0.25 mg (1 to 2.5 mL) IV slowly once
Use: For the treatment of acute asthmatic attacks to relieve bronchospasm not controlled by inhalation or subcutaneous administration of other solutions of the drug

Usual Adult Dose for Allergic Reaction : Auto-Injector :
30 kg or greater: 0.3 mg IM or subcutaneously into anterolateral aspect of thigh; repeat as needed

Usual Adult Dose for Anaphylaxis :
Auto-Injector :
30 kg or greater: 0.3 mg IM or subcutaneously into anterolateral aspect of thigh; repeat as needed

Usual Adult Dose for Hypotension, Shock :
Injectable Solution of 1 mg/mL (1:1000): 0.05 to 2 mcg/kg/min IV and titrate to achieve desired mean arterial pressure (MAP)
-Dosage may be adjusted periodically, such as every 10 to 15 minutes in increments of 0.05 to 0.2 mcg/kg/min to achieve desired blood pressure goal

Usual Adult Dose for Bradyarrhythmia :
- The AHA recommends :
2 to 10 mcg/min IV and titrate to patient response
-Alternate dose: 0.1 to 0.5 mcg/kg/min (in a 70 kg patient, 7 to 35 mcg/min) IV; titrate to effect
Use: For patients with symptomatic bradycardia, particularly if associated with hypotension, for whom atropine may be inappropriate or after atropine fails

Usual Pediatric Dose for Cardiac Arrest :
- The AHA recommends :
Neonates :
-IV: 0.01 to 0.03 mg/kg (1:10,000 injectable solution) IV once
- Endotracheal: 0.05 to 0.1 mg/kg (1:10,000 injectable solution) via endotracheal route once may be reasonable while attempting to gain IV access

Usual Pediatric Dose for Allergic Reaction :
- Auto-Injector :
15 to 30 kg: 0.15 mg IM or subcutaneously into anterolateral aspect of thigh; repeat as needed 30 kg or greater: 0.3 mg IM or subcutaneously into anterolateral aspect of thigh; repeat as needed

Usual Pediatric Dose for Anaphylaxis :
- Auto-Injector :
15 to 30 kg: 0.15 mg IM or subcutaneously into anterolateral aspect of thigh; repeat as needed 30 kg or greater: 0.3 mg IM or subcutaneously into anterolateral aspect of thigh; repeat as needed.

Side effects

nausea , Headache , vomiting , Injection-site reaction , peripheral nephropathy , Hypocalcemia

Alerts

When Epinephrine Injection is administered intravenously, titrate the infusion while monitoring vital signs. Invasive arterial blood pressure monitoring and central venous pressure monitoring are recommended. Because of varying response to epinephrine, dangerously high blood pressure may occur.
Patients receiving monoamine oxidase inhibitors (MAOI) or antidepressants of the triptyline or imipramine types may experience severe, prolonged hypertension when given epinephrine. When Epinephrine Injection is administered intravenously, the infusion site should be checked frequently for free flow.
Avoid extravasation of epinephrine into the tissues, to prevent local necrosis. When Epinephrine Injection is used for the treatment of anaphylaxis, the most appropriate location for administration is into the anterolateral aspect of the thigh (vastus lateralis muscle) because of its location, size, and available blood flow. Injection into (or near) smaller muscles, such as in the deltoid, is not recommended due to possible differences in absorption associated with this use.
Do not administer repeated injections of epinephrine at the same site, as the resulting vasoconstriction may cause tissue necrosis. Injection into the buttock may not provide effective treatment of anaphylaxis and has been associated with the development of Clostridial infections (gas gangrene). Epinephrine is a strong vasoconstrictor. Accidental injection into the digits, hands or feet may result in loss of blood flow to the affected area and has been associated with tissue necrosis.

Points of recommendation

Advise patients or their caregivers about common adverse reactions associated with the use of epinephrine, including an increase in heart rate, the sensation of a more forceful heartbeat, palpitations, sweating, nausea and vomiting, difficulty breathing, pallor, dizziness, weakness or shakiness, headache, apprehension, nervousness, or anxiety. These symptoms and signs usually subside rapidly, especially with rest, quiet and recumbent positioning.
Warn patients with a good response to initial treatment about the possibility of recurrence of anaphylaxis symptoms and instruct patients to obtain medical attention if symptoms return.
Advise patients with diabetes that they may develop increased blood glucose levels following epinephrine administration.
Rare cases of serious skin and soft tissue infections, including necrotizing fasciitis and myonecrosis caused by Clostridia (gas gangrene), have been reported at the injection site following epinephrine injection for anaphylaxis. Advise patients to seek medical care if they develop signs or symptoms of infection, such as persistent redness, warmth, swelling, or tenderness, at the epinephrine injection site [see Warnings and Precautions.

Pregnancy level

C


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