Epinephrine: administration mode and indications

Epinephrine, better known as adrenaline, is a hormone and a neurotransmitter used in emergency situations in which there is a cardiac arrest.

This drug has historically been used to treat bronchospasm and hypoglycemia. However, nowadays we have more specific drugs for these pathologies.

This substance increases the heart rate, contracts the blood vessels, dilates the airways and participates in the fight or flight reaction of the nervous system in emergency situation.

Speaking in a slightly more technical way, adrenaline is a catecholamine. It is a monoamine that is synthesized in the adrenal glands and whose precursors are phenylalanine and tyrosine.

How is epinephrine given?

Epinephrine comes prepared as a solution to be administered with an injectable. In addition, it can be administered in different ways, as necessary:

  • Intramuscular (IM)
  • Subcutaneous
  • Intravenous (IV).
  • Intracardiac: only in cases of extreme severity, and if the intravenous route is not practicable.

The last two types of administration they have to be carried out in the hospital, under cardiac monitoring and previously diluting the epinephrine solution in water for injection, which can be:

  • 0.9% sodium chloride solution
  • Glucose 5%
  • Glucose 5% in 0.9% sodium chloride solution.

In addition, in order to avoid the degradation of the drug by light or oxidation, It is recommended to use the product just after dilution. Regarding the dosage and the route of administration, both parameters will depend on the diagnosis and the clinical situation of the patient.

However, in an emergency situation always a fast route of administration must be used, as is the intravenous one.

Indications of epinephrine

As we have seen, epinephrine is a solution that It is collected in an ampoule of different concentrations. Among its medical applications, we can mention the following:

Heart attack

In addition to cardiac arrest, Adrenaline is also given in order to treat other heart problems, such as arrhythmias that result from decreased or absent cardiac output.

The action of epinephrine it consists of provoking vasoconstriction and increasing the cardiac output. In other words, it contracts the heart and increases its heart rate to 'revive' it.

Discover: Do we know how to recognize the symptoms of a heart attack?


Epinephrine is also used as a first-line treatment for anaphylaxis. This pathology is triggered when an allergic condition becomes worse and can lead to death by extreme bronchoconstriction.

In these cases, This drug is suitable for its dilator effects at the level of the respiratory tract.

Joint administration with local anesthetics

Epinephrine is added to a series of local anesthetics that are given as injectables. The reason for this combination is that the vasoconstrictor effects of adrenaline allow to delay absorption and, in this way, prolong the effect of the anesthetic drug.

In addition, some of the adverse effects of the use of local anesthetics with epinephrine could be due to the action of the latter, for example:

  • Apprehension.
  • Tachycardia.
  • Tremors

What are the possible adverse effects?

The use of this substance it is not free of possible adverse effects and complications, especially in its intravenous and intracardiac administration. The possible adverse reactions to epinephrine are:

  • Palpitations and tremors.
  • Tachycardia
  • Cardiac arrhythmias.
  • Anxiety and hypertension.
  • Headaches
  • Acute pulmonary edema.

Further, its use is contraindicated in a series of patients, as those who are being treated with nonselective beta-blocking drugs.

This contraindication is due to the interaction of both drugs could cause severe hypertension, even to trigger a cerebral hemorrhage.

Although many people believe that the administration of epinephrine can cause heart failure due to its high vasoconstrictor effect, this is not true.

The coronary arteries only have one type of receptor that, when interacting with adrenaline, they trigger signals for vasodilation to occur, not vasoconstriction.

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Epinephrine or adrenaline it is a drug administered by different routes, according to the patient's clinical situation, for the treatment of cardiac arrest and anaphylactic reactions, mainly.

There are formulations of epinephrine prepared for self-injection which are indicated in patients at risk of suffering anaphylactic shock.

Like all medications, this catecholamine is not free of adverse effects, what should be taken into account when administering the epinephrine solution.