Epinephrine (Adrenalin Chloride®)

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Epinephrine (Adrenalin Chloride®)

By: Dr. Dawn Ruben

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Overview

The autonomic (involuntary) nervous system is divided into the sympathetic (flight or fight response) and parasympathetic branches. In general, these two systems oppose each other.

When stimulated, the sympathetic system increases heart rate, blood pressure and cardiac activity. The pupils dilate and gastrointestinal function decreases.

Sympathetic activity is sent through involuntary (autonomic) nerves and from the adrenal glands through the blood stream.

The parasympathetic system, working largely through a nerve called the vagus nerve, slows heart rate, reduces blood pressure and stimulates gastrointestinal function and digestion.

Cells contain targets, called receptors, that are stimulated by chemicals released from nerves. In the sympathetic system, the chemical transmitter released by nerves is called norepinephrine and the chemical released by the adrenal glands is called epinephrine or adrenaline. The receptors (cell targets) for these chemical are the alpha-beta adrenergic receptors.

Epinephrine is a natural hormone, but is also available as a drug for medical use.

Epinephrine belongs to the class of drugs known as an adrenergic agents. There are numerous effects of epinephrine, including increasing blood sugar levels, dilating the pupil of the eye and directly stimulating the heart and blood vessels, increasing the heart rate and increasing blood pressure.

Epinephrine also fights the effects of histamine, a substance released in severe allergic reactions.

Epinephrine also relaxes the smooth muscles of the bronchial tree, causing the bronchial tubes to dilate.

Epinephrine is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.

Brand Names and Other Names

This drug is registered for use in humans and animals.

Human formulations: Adrenalin Chloride® (P-D) and generic preparations

Veterinary formulations: Variety of generic preparations

Uses of Epinephrine

Epinephrine is used to treat severe allergic (anaphylactic) reactions because it can prevent or minimize the effects of histamine.

It is also used to help in severe asthmatic attacks to dilate the bronchial tubes.

Epinephrine is used to stimulate the heart in CPR.

In some cases, epinephrine has been used to increase blood pressure during anesthesia or a low blood pressure crisis.

Precautions and Side Effects

While generally safe and effective when prescribed by a veterinarian, epinephrine can cause side effects in some animals.

Epinephrine should not be used in animals with known hypersensitivity or allergy to the drug.

Epinephrine should be avoided in pregnant animals or those in labor.

It should be used with caution in animals experiencing shock.

It should not be given to animals with certain heart irregularities such as ventricular premature beats (those starting from the bottom of the heart).

Epinephrine may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with epinephrine. Such drugs include certain antihistamines, propranolol and certain diuretics.

Epinephrine can result in a feeling of fear or anxiety and may cause tremors, vomiting, high blood pressure or heart rhythm irregularities.

How Epinephrine Is Supplied

Epinephrine is available in 0.1 mg/ml and 1 mg/ml solutions. There is also a powder form available for inhalation.

Dosing Information

Medication should never be administered without first consulting your veterinarian.

For CPR, a variety of epinephrine doses have been used and the dose may change or need to be repeated every five minutes until a heart beat can be restored, if possible.

For severe allergic reactions or asthma crisis, 0.005 to 0.01 mg per pound (0.01 to 0.02 mg/kg) is given.

The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects.