- Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced by the adrenal glands.
- It plays a key role in the body’s “fight-or-flight” response by increasing heart rate, expanding airways, raising blood pressure, and mobilizing energy stores.
Chemical Structure & Formula
- Chemical Formula: C₉H₁₃NO₃
- Structure:
Advertisements
Mechanism of Action (Detailed)
- Epinephrine acts on both α and β adrenergic receptors, with different effects based on the dose:
- Low doses: β2 > β1 > α (vasodilation, increased heart rate, bronchodilation).
- High doses: α > β1 > β2 (vasoconstriction, increased blood pressure).
Effects on Different Organs
-
Cardiovascular:
- β1: Increases heart rate (positive chronotropic), force of contraction (positive inotropic), and cardiac output.
- α1: Vasoconstriction at high doses (increases BP).
- β2: Vasodilation at low doses (reduces diastolic BP).
-
Respiratory:
- β2: Bronchodilation (useful in asthma and anaphylaxis).
-
Metabolic:
- β2: Increases glycogenolysis and lipolysis.
- α2: Inhibits insulin release, leading to hyperglycemia.
Advertisements
Side Effects of Epinephrine
- Hypertension & Arrhythmias
- Tachycardia & Palpitations
- Hyperglycemia
- Tremors (β2-mediated skeletal muscle activation)
Clinical Uses of Epinephrine
- Anaphylactic shock – First-line treatment.
- Cardiac arrest – Used in Advanced Cardiac Life Support (ACLS).
- Severe asthma attack – As a bronchodilator.
- Local vasoconstriction – Used with local anesthetics to prolong effect.
Advertisements
Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!
