Epinephrine

INTRODUCTION:

• Epinephrine/adrenaline – Hormone secreted by medullas of adrenaline gland.
• Formed from Tyrosine.
• Metyrosine inhibits rate limiting step in synthesis of epinephrine.

MOA:

• Stimulates heart by accelerating slow depolarization of SA nodal cells, during phase 4 AP. 

USES:

• Epinephrine found in small amount essential for maintaining cardiovascular homeostasis due to its ability to direct blood to tissue under stress.
• Acts a stimulant in cardiac arrest.
• Vasoconstrictor in anaphylactic shock (I.V.)
• As Bronchodilator
• Anti-spasmodic in bronchial asthma.
• Sympathomimietic.
• Causes increase in mean blood pressure, heart rate & cardiac output on IV infusion.
• Uveitis glaucoma, Open angle glaucoma & Neovascular glaucoma – 
• Reduces aqueous production & increases outflow facility.
• Causes glycogenoloysis.
• Gluconeogenesis by inhibiting insulin secretion.
• Bupivacaine toxicity.
• Actively bleeding peptic ulcer can be managed endoscopically by injection therapy using epinephrine with concentration 1 in 10,000.
• In Hepatomegaly & Hypoglycemia
• Exception: A diagnosis of type I glycogen storage disease (Von Girke’s disease) should be suspected whenever there is hepatomegaly with hypoglycemia that is unresponsive to glucagon or epinephrine
• Epinephrine secreted by Pheochromocytoma casuing clinical manifestations.
• Used to prolong duration of action & decreases systemic toxicity of local anaesthetics.

STORAGE:

•  Adrenaline – Photo-sensitive.
•  Do not store in cartons.
•  Store below 25 degree.
•  Do not refrigerate of freeze.

INDICATIONS:

• Emergency treatment in anaphylaxis. 
• In anaphylaxtic shock – Given 0.5ml in 1:1000 solution (0.5mg) i.m/s.c inj. 
• Lateral thigh route is preferred (IM).
• Bronchospasm, Asthma, Caridac Failure.
• Adult: 0.2–1mg (preferred) or IM (avoid buttocks) every 4 hrs as needed.
• Children: 0.01mg/kg (max 0.5mg) every 4 hrs as needed.
• In the beginning of resuscitation efforts, 0.5 mg of epinephrine is administered subcutaneously that acts via:
• Alpha-1 receptors in vascular smooth muscle.
• beta-1 receptors in the heart.
• beta-2 receptors in bronchial smooth muscle.

CONTRA-INDICATION:

• High Blood Pressure, Diabetes & Heart Disease.
• Children under 30 kg.
• Long term lung disease.
• Mental health problem or with brain damage

SIDE EFFECTS:

• Abnormal and decreased touch sensation.
• Arm, back or jaw pain.
• Bleeding discoloration of skin.
• Fainting
• Dizziness
• Causes hyperglycemia by increased glucagon & decreased insulin secretion
•  Headache & nervousness.
• Stress Syndrome:
• In surgical stress, Epinephrine is increased.