What You Need to Know about Sympathomimetic Drugs

Here, we’ll be going right into the anaphylactic drugs.

While eating at a restaurant, your client has suddenly developed an anaphylactic reaction after devouring a plateful of mixed seafood. After a couple of minutes, the person goes into a severe allergic reaction. The moment a person experiences an anaphylaxis due to something he or she ate, inhaled, or came in contact with, the result would be decreased oxygen perfusion to the body.

A Background on Anaphylaxis

It doesn’t matter if it’s a heart attack, a stroke, a deep vein thrombosis, or a pulmonary embolism; for as long as the pathways for blood-rich oxygen are blocked, the body becomes compromised.

In the case of anaphylaxis, the blood vessels become wider, causing low pressure which is equated to low perfusion and essentially, low oxygen supply. Therefore, the goal of anaphylactic drugs is to reverse this consequence.

Sympathomimetic Drugs

The first type of anaphylactic drug is the sympathomimetic drug. Sympathomimetic drugs are meant to mimic the role of the sympathetic nervous system, acting on the fight and flight response. Tapping the sympathetic nervous system will cause increased blood flow to the three main organs in the body – the lungs, the heart, and the brain. Thereby decreasing the rest and digest phase and getting the required amount of oxygen where the body needs it. This is how sympathomimetic drugs are created – to imitate the parasympathetic response system.

The sympathomimetic drugs that are used in hospitals are:

  • Epinephrine
  • Isoproterenol
  • Ephedrine

Administration of either one of these drugs would immediately cause vasoconstriction, increasing perfusion by shunting blood to the brain, lungs, and heart.


Among these three kinds, epinephrine is the most common medication used in any healthcare setting, especially with emergency cases. Epinephrine is what’s given first during a cardiac arrest to jumpstart the heart that stopped beating. The body naturally creates epinephrine or what is also known as adrenaline; therefore, epinephrine is just adrenaline in a bottle.

How to Remember Epinephrine

Epinephrine or sympathomimetic drugs have several effects on the body, to quickly recall what these drugs to do the body, remember the acronym, NASCAR.

  • N – nervousness
  • A – anxiety
  • S – sugar in the blood is increased
  • C – cardiac arrest
  • A – allergic reaction
  • R – respiratory bronchodilator

A Summary

Sympathomimetic drugs stimulate the body’s oxygen and blood perfusion by imitating the sympathetic nervous system’s effects. Introduction of epinephrine to the body can cause adverse reactions like nervousness, anxiety, and increased blood sugar. Sympathomimetic drugs also cause headaches, palpitations, tremors, and dizziness.

Aside from cardiac arrest, epinephrine is also used for the anaphylactic reaction that can be caused by several factors like food, medication, latex, and insect stings. A secondary effect of sympathomimetic drugs is respiratory bronchodilation or lung expansion that is due to the shunting of blood to the respiratory tract.

So that’s sympathomimetic drugs in a nutshell. For those who want to brush up on the topic of sympathetic versus parasympathetic nervous system, we have a lecture dedicated entirely on that matter. Or if you just want to check out our other nursing-related videos and NCLEX® reviews, head on to our Simple Nursing website and YouTube channel.