From the Guidelines
Yes, you should give epinephrine immediately for a patient experiencing drug anaphylaxis. Administer 0.2 to 0.5 mg of epinephrine (1:1000 concentration) intramuscularly in the mid-outer thigh for adults, as recommended by the 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. This can be repeated every 5 to 15 minutes if symptoms persist. Position the patient lying flat with legs elevated unless they have respiratory distress. After giving epinephrine, establish IV access, administer oxygen if available, and consider additional medications such as antihistamines and corticosteroids. Monitor vital signs continuously and be prepared to perform CPR if needed. Epinephrine works rapidly to reverse the life-threatening effects of anaphylaxis by constricting blood vessels to increase blood pressure, relaxing airway muscles to improve breathing, and reducing hives and swelling. It is the first-line treatment because it addresses multiple physiological aspects of anaphylaxis simultaneously, and delaying administration increases mortality risk.
Some key points to consider when administering epinephrine for anaphylaxis include:
- The dose of epinephrine should be 0.2 to 0.5 mg (1:1000) intramuscularly, to be repeated every 5 to 15 min as needed 1
- In patients with anaphylactic shock, close hemodynamic monitoring is recommended 1
- Immediate referral to a health professional with expertise in advanced airway placement, including surgical airway management, is recommended 1
- Antihistamines and corticosteroids should not be considered as substitutes for epinephrine, but may be used as additional treatments 1
- The patient should be kept under observation in a setting capable of managing anaphylaxis until symptoms have fully resolved 1
It's also important to note that epinephrine has a narrow toxic-therapeutic index, and rare but severe adverse effects can occur, such as ventricular arrhythmias, angina, myocardial infarction, pulmonary edema, sudden sharp increase in BP, and intracranial hemorrhage 1. However, the benefits of epinephrine in treating anaphylaxis far outweigh the risks, and it should be administered promptly in any patient with signs of a systemic allergic reaction.
From the FDA Drug Label
Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis. Yes, epinephrine is indicated for the emergency treatment of anaphylaxis, including anaphylaxis caused by drugs 2.
- The signs and symptoms of anaphylaxis include flushing, apprehension, syncope, tachycardia, thready or unobtainable pulse associated with hypotension, convulsions, vomiting, diarrhea and abdominal cramps, involuntary voiding, airway swelling, laryngospasm, bronchospasm, pruritus, urticaria or angioedema, swelling of the eyelids, lips, and tongue. Administration should be cautious in patients taking other sympathomimetic agents or certain other medications, as listed in the drug interactions section 2.
From the Research
Anaphylaxis Treatment
- Anaphylaxis is a life-threatening systemic reaction that requires prompt recognition and treatment 3, 4, 5.
- Epinephrine is the first-line treatment for anaphylaxis and should be administered intramuscularly as soon as the diagnosis is suspected 3, 4, 6, 5.
- The administration of epinephrine should not be delayed, and it is critical for survival 3, 4, 5.
- Antihistamines and corticosteroids are second-line medications and should never be given in lieu of, or prior to, epinephrine 3, 4, 5.
Administration of Epinephrine
- Epinephrine should be administered intramuscularly, into the anterolateral thigh, as soon as the diagnosis of anaphylaxis is suspected 3, 4.
- For patients unresponsive to repeated intramuscular injections, a continuous infusion of epinephrine should be started 3.
- A second dose of epinephrine may be required if symptoms of severe anaphylaxis fail to resolve following an initial dose 7.
Additional Treatment
- Aggressive fluid resuscitation should be used to treat the intravascular volume depletion characteristic of anaphylaxis 3.
- Supplemental oxygen, intravenous fluids, antihistamines, and corticosteroids should not delay the administration of epinephrine 3, 4, 5.
- Patient observation and disposition should be individualized, as there is no well-defined period of observation after resolution of signs and symptoms 3.