Clinical Intervention Protocol for Intramuscular Epinephrine 2026

Clinical Protocols for the Administration of Intramuscular Epinephrine

The clinical intervention protocols for primary care paramedics in the year 2026 provide exhaustive guidelines for the administration of intramuscular epinephrine, as detailed on page 186. Epinephrine is primary indicated in the pre-hospital setting for life-threatening emergencies involve either anaphylaxis or severe bronchoconstriction. The implementation of these protocols requires a precise assessment of the patient's clinical presentation and adherence to weight-based dosing and specific timing for repetition.

Indications and Contraindications for Anaphylaxis

Epinephrine is the first-line treatment for an anaphylactic reaction. The administration is predicated on the clinical observation of signs and symptoms consistent with a systemic allergic reaction or anaphylaxis. For patients presenting with a clinical table of an anaphylactic reaction, there are no absolute contraindications to the administration of epinephrine, given the critical and potentially fatal nature of the condition. In the context of anaphylaxis where cardiac arrest (ACR) has occurred, regardless of the patient's age or whether they have received prior doses of the drug before the arrival of paramedics, a single intramuscular dose must be administered as soon as possible. This intervention must not interrupt or delay cardiopulmonary resuscitation (CPR) or ventilation procedures. Decisions regarding the timing of intubation in these specific scenarios should be based on the quality of ventilations provided to the patient.

Indications and Contraindications for Bronchoconstriction

In the management of bronchoconstriction, the criteria for epinephrine administration are more restrictive. The patient must present with a clinical table of bronchoconstriction and must specifically be an asthmatic under the age of $40$ years. Furthermore, the patient must display signs of respiratory insufficiency. A critical clinical caveat exists: if the sole indicator of respiratory insufficiency is respiratory distress that proves refractory to standard treatments, epinephrine should only be considered after the patient has received three full treatments of salbutamol/ipratropium. Unlike anaphylaxis, there is a specific contraindication for epinephrine in the context of bronchoconstriction: it must not be administered if the patient has a known history of coronary artery disease, also referred to as MCAS (Maladie Coronarienne).

Presentation and Weight-Based Dosage

The standardized presentation for epinephrine in this protocol is a concentration of $1\,mg/ml$, which corresponds to a ratio of $1:1000$. To minimize the risk of dosage errors, paramedics are encouraged to use $1\,ml$ vials of this specific concentration. The dosage is determined strictly by the patient's weight category. For patients weighing less than $25\,kg$, the dose is $0.15\,mg$, requiring a volume of $0.15\,ml$. For patients weighing between $25\,kg$ and $49\,kg$, the dose is $0.3\,mg$, which corresponds to a volume of $0.3\,ml$. For patients weighing $50\,kg$ or more, the dose is increased to $0.5\,mg$, requiring a volume of $0.5\,ml$.

Repetition Protocols and Route of Administration

The route of administration for all specified conditions in this protocol is exclusively intramuscular (IM). The rules for repeating doses differ significantly based on the indication. For anaphylaxis, epinephrine can be repeated every $5\,minutes$ if the patient's condition shows signs of deterioration. If the patient shows no signs of improvement or if the original indications for treatment persist without worsening, the dose can be repeated every $10\,minutes$. Crucially, there is no maximum number of doses for anaphylaxis. Conversely, when treating bronchoconstriction, paramedics are limited to a single IM dose with no provision for repetition. If a patient receiving treatment for anaphylaxis had already received one or more doses of epinephrine prior to the arrival of the paramedics, the paramedics are still required to administer a dose if the clinical conditions for administration remain present.

Adverse Effects and Clinical Risks

Epinephrine is a potent sympathomimetic amine that can cause several common adverse effects. These include neurological symptoms such as nervousness, tremors, anxiety, dizziness, and headaches. Gastrointestinal symptoms like nausea and vomiting are also possible. Cardiovascular and integumentary effects include pallor, tachycardia, and palpitations. Additionally, patients may experience hyperglycemia and dyspnea. While less common, there are rarer but more severe clinical risks associated with epinephrine administration, including severe respiratory distress, cerebral hemorrhage, cerebrovascular accident (AVC/stroke), cardiac arrhythmias, hypertension (HTA), angina, and myocardial infarction.

Pharmacokinetics and Pharmacodynamics of Intramuscular Epinephrine

Classified as a sympathomimetic amine, epinephrine acts rapidly upon intramuscular injection. The onset of action for its vasopressive and bronchodilatory effects ranges from $5$ to $10\,minutes$. The drug has a very short half-life, lasting approximately $2$ to $3\,minutes$. Despite this short half-life, the maximum duration of the clinical effect is between $1$ and $4\,hours$. Epinephrine undergoes metabolism in both the liver (hepatic) and peripheral tissues. The resulting metabolites are subsequently eliminated by the kidneys through renal excretion.