Medical Emergencies in the Dental Office – Part Two


Let’s look at another essential  drug that is required to be in every dental office…Epinephrine…Also known as Adrenalin.

Why do we need to have epinephrine in the office? Why is it an essential drug?

An acute severe allergic reaction can happen to anyone in the dental office…whether you’re a patient or someone in the waiting room i.e. one may be allergic to the latex in the dentist’s gloves or an individual with a severe nut allergy, who is just sitting in the waiting area near someone eating nuts, may be triggered by the aroma of the nuts.

What is Epinephrine?

It is an endogenous catecholamine. Endogenous refers to substances that originate within the body.

Catecholamines consist of hormones and neurotransmitters. The main ones are dopamine, norepinephrine (noradrenaline) and epinephrine (adrenaline). Have you ever heard the expression, the adrenaline is flowing? This occurs when an individual is feeling anxious, stressed, angry or excited. When the adrenaline is flowing, it affects both the respiratory (breathing) and cardiovascular (pumping action of the heart) systems.

Effects of Epinephrine on the body systems…Let’s get technical.

Epinephrine affects the heart by acting on different receptors:
1) Stimulation of alpha one receptors – This causes vasoconstriction.
2) Stimulation of beta one receptors – This causes increased contractility of the heart.
3) Stimulation of beta two receptors – This causes bronchodilation.

What Does this all mean?

To help us better understand the above (1-3), we will look at what happens during an anaphylactic reaction.

Anaphylaxis occurs during an acute allergic episode and it can be life threatening. An acute allergic reaction can result in the following:
1) Hypotension – low blood pressure.
2) Laryngeal edema – swelling and accumulation of fluids in the area of the vocal cords.
3) Bronchospasm – tightening and closing up of the airway passages that lead to the lungs.

The above are the major signs of an anaphylactic reaction.

The less severe signs of an allergic reaction are hives, itching, rash and redness. These ‘less severe’ signs can be treated with Benadryl (diphenhydramine)….we will look at Benadryl in the next blog.

How does epinephrine reverse an allergic reaction?

Epinephrine ‘corrects’ the three life threatening symptoms mentioned above and it does so by acting on the three receptors mentioned previously. It reverses the severe effects that are occurring so quickly within an individual…time is of the essence…there is no time to spare!

Epinephrine’s mechanism of action

Epinephrine has to clear up this whole situation…and quick!

It acts on the various receptors mentioned previously and increases blood perfusion (flow) to the area that needs it the most…the brain.

Action on beta one receptors: This acts to increase the force of contraction of the heart. This results in more oxygenated blood being delivered to the brain.

Action on beta two receptors: Epinephrine acts on the Bronchial system (relates to the lungs and proper breathing). The epinephrine acts to reverse the bronchospasm or ‘closing off’ of the bronchi. It acts as a bronchodilator.

Action on alpha one receptors: Epinephrine causes vasoconstriction (closing) of the peripheral blood vessels…peripheral refers to the blood vessels of the skin and extremities (arms and legs). This results in less oxygenated blood going to the skin, arms and legs. This is a desirable effect because it’s important to have the oxygenated blood go to the brain and vital organs…we need to have oxygenated blood going to the brain…did you know that it takes only four minutes of oxygen deprivation for one to get brain damage…this is why blood flow to the brain is crucial.

Epinephrine acts rapidly and has a short duration of action (5-10 minutes). After 5-10 minutes, 911 have usually made their way to the dental office to help deal with the emergency. Otherwise, another dose of epinephrine can be administered if necessary (usually 10-15 minutes later).


This was a very technical blog.

I hope anyone reading this was able to appreciate how important epinephrine is in dealing with an acute and severe allergic reaction. This is why epinephrine is a key drug to have in the office…it saves lives!

Yours in excellent dental health,

Dr. F. Keshavarz Dentistry, Brampton Dentist

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Anaphylaxis is a severe acute allergic reaction that progresses quickly and can lead to death;

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