Refractory Anaphylaxis in the ED: Escalate Early

The patient has hives, wheezing, and a blood pressure that is falling despite the first intramuscular epinephrine dose. Someone asks whether to give a second dose. Someone else reaches for diphenhydramine. The room feels busy, but the next decision is simple: keep treating the physiology that can kill the patient now.

Refractory anaphylaxis is rare, but it punishes delay. The practical move is to recognize when standard intramuscular treatment has not worked, start resuscitation in parallel, and escalate to a carefully monitored epinephrine infusion rather than improvise an intravenous bolus. The evidence base is not perfect, so the team must know which steps are firm and which are expert-consensus territory. (A 2024 overview of refractory anaphylaxis)

Start with the first-line treatment, not the label

Anaphylaxis is a clinical diagnosis. The 2023 practice parameter update revised diagnostic criteria and describes different patterns of presentation, so a patient does not need to arrive with every classic feature before treatment starts. (2023 practice parameter update) Give intramuscular epinephrine promptly when anaphylaxis is suspected. IM epinephrine remains first-line treatment across current guidelines in both community and hospital settings. (Refractory-anaphylaxis review)

For adults, current guideline doses commonly fall around 0.3–0.5 mg IM, or 10 micrograms/kg up to a 0.5 mg maximum, depending on the guideline and device. Repeat dosing is generally recommended every 5–15 minutes when symptoms persist. Reassess airway, breathing, circulation, mental status, and response after each dose. (Guideline comparison table)

Keep a shocked patient supine with the legs raised when feasible. Cardiovascular collapse can worsen when a patient with anaphylaxis stands or is moved upright. (Positioning guidance)

Decide when the IM pathway has failed

Definitions differ. The Resuscitation Council UK definition uses inadequate response after two IM doses. A US expert panel definition uses three or more appropriate doses, or the start of an IV epinephrine infusion, along with symptom-directed care such as fluids or oxygen. A pragmatic ED trigger is persistent shock, hypoxia, airway swelling, or altered mental status after two appropriate IM doses and initial fluid resuscitation. That trigger should activate help, monitoring, vascular access, and a shared plan rather than another untracked dose. (Definitions of refractory anaphylaxis)

Assign one clinician to the airway, one to medication and timing, one to access and fluids, and one to document the response. Call for critical care or anesthesia support early when the patient worsens. A 2024 review recommends simulation training because this condition is uncommon and high-stakes. (Simulation recommendations)

Start continuous cardiopulmonary monitoring. Establish peripheral IV access; use intraosseous access if IV access is not available or more access is needed. Arterial and central access may follow during ongoing shock, but should not delay resuscitation. (Monitoring and access guidance)

Resuscitate the physiology in parallel

Severe anaphylaxis causes rapid vascular leak. A large volume of plasma can leave the circulation within minutes, producing both absolute and relative hypovolemia. Give crystalloid early for hypotension, with the review describing 20–30 mL/kg as a general starting range while noting that guideline volumes differ and the evidence is limited. Use the patient's blood pressure, perfusion, lung examination, and response to guide repeated boluses. (Fluid-resuscitation review)

Oxygen and airway support belong in the same plan. Give supplemental oxygen for hypoxia or shock and treat severe bronchospasm or upper-airway swelling without losing focus on epinephrine. If airway edema is progressing, call for the most experienced airway operator available and prepare for a difficult airway while the patient still has oxygen reserve. The refractory-anaphylaxis review lists respiratory compromise requiring oxygen or mechanical support among markers of a severe, treatment-resistant reaction. (Airway and oxygen discussion)

Do not let an adjunct become the main event. Antihistamines may help selected cutaneous symptoms, but they do not replace epinephrine for shock or airway compromise. The 2023 practice parameter emphasizes prompt epinephrine use and specific counseling about how and when to use it. (2023 practice parameter update)

Move to an epinephrine infusion safely

When significant symptoms persist after two or three appropriate IM doses and fluids, current guidance commonly recommends an IV epinephrine infusion. The dose and preparation vary across guidelines. Examples in the 2024 review include starting around 0.05–0.1 micrograms/kg/min and titrating to the clinical response, while the US table lists a fixed starting dose of 2 micrograms/min with titration up to 10 micrograms/min. Use the concentration and pump protocol your department has checked in advance. (IV infusion guidance and guideline differences)

This is the moment to slow down enough to be safe. Use a dedicated line when possible. Label the line and pump. Confirm the concentration aloud. Monitor blood pressure, rhythm, oxygenation, and signs of excessive catecholamine effect. The review warns that IV epinephrine has more frequent adverse effects than IM treatment and can cause life-threatening arrhythmia when administered by people unfamiliar with the route. IV bolus epinephrine is not the routine next step for community or non-perioperative anaphylaxis. (Safety of IV epinephrine)

Persistent hypotension despite an epinephrine infusion and adequate fluids requires critical care-level resuscitation. Additional vasopressors such as norepinephrine or vasopressin may be considered by trained clinicians, but no high-quality evidence establishes one as the preferred second-line drug. Glucagon is recommended by many guidelines for patients taking beta-blockers, yet the evidence is mostly case reports. Say that out loud in the handoff: the indication is plausible, the data are thin, and the patient needs close monitoring. (Second-line therapy and evidence limits)

Dr. Chet's Take

I have treated enough unstable allergic patients to know that the room can become distracted by the rash. The rash is not the emergency. The falling pressure, tight airway, and failing ventilation are the emergency. This article gets the central point right: give IM epinephrine early, give fluid when shock is present, and recognize the patient who is not responding before the third dose disappears into the noise of the resuscitation.

That being said, the infusion step is where bedside confidence often outruns preparation. I do not want a clinician calculating a concentration from memory while a patient is peri-arrest. I want the department to have a checked mixing instruction, a pump library entry, a line-labeling habit, and a simulation rep that includes the nurse who will actually run the infusion. The honest answer is that the second-line evidence is thin. That is not permission to drift. It is a reason to make the first decisions disciplined.

If you are the attending, name the trigger for escalation out loud: persistent shock or respiratory compromise after appropriate IM epinephrine and fluids. Assign the airway, medication, access, timing, and consultant calls. Then document the response to each intervention. Anaphylaxis is rare enough that deliberate practice matters.

Key Takeaways

• Give IM epinephrine promptly for suspected anaphylaxis; do not wait for every classic sign. (2023 practice parameter update)
• Treat persistent shock, hypoxia, airway swelling, or altered mental status after two appropriate IM doses and fluids as a trigger for escalation. (Refractory-anaphylaxis definitions)
• Resuscitate with oxygen, IV or IO access, and crystalloid while the epinephrine response is assessed. (Fluid and monitoring guidance)
• Use a monitored IV epinephrine infusion for refractory disease; avoid routine IV boluses outside settings with specialist training and monitoring. (IV epinephrine safety review)
• Practice the escalation sequence in the EM-Sim scenario catalog, and compare team-based clinical training with EMS-MedSim when your learning goal includes prehospital handoff.

If you're a emergency physician, EM resident, medical student, or APP trying to understand how AI will actually impact your clinical practice — not just the hype — I put together a free practical guide. You can download it here: AI in EM Survival Guide.

The clinical problem is shared across organizations, which is why the Global MedOps Command hub connects the EM-Sim work to broader medical-operations training.

FAQ

When should I repeat epinephrine for anaphylaxis in the ED?

Repeat IM epinephrine when symptoms persist, commonly every 5–15 minutes according to the guideline and the patient's response. Do not substitute an antihistamine for epinephrine when the patient has shock, hypoxia, or airway compromise. (Guideline comparison)

What is refractory anaphylaxis?

Definitions vary. A practical ED definition is persistent clinically important airway, breathing, or circulation compromise after two appropriate IM epinephrine doses plus initial fluid resuscitation. The exact threshold differs among expert groups, so use your local escalation protocol and call for critical care help early. (Definitions and thresholds)

When should I start an epinephrine infusion for anaphylaxis?

Consider an IV epinephrine infusion when significant symptoms persist after two or three IM doses and adequate fluid therapy. Use a checked departmental protocol, a pump, and continuous cardiopulmonary monitoring because dose and concentration errors can cause serious harm. (Infusion recommendations)

Should I give an IV epinephrine bolus for refractory anaphylaxis?

Routine IV boluses are not the next step for non-perioperative ED anaphylaxis. The IV route carries more risk, and the review describes infusion-based, titrated treatment as the safer approach when skilled staff and monitoring are available. (IV route safety discussion)

What should I do if the patient takes a beta-blocker?

Continue to treat the anaphylaxis with epinephrine and fluids. Many guidelines suggest glucagon for epinephrine-resistant shock in patients taking beta-blockers, but the supporting evidence is limited; involve critical care and monitor closely. (Glucagon evidence review)

Sources

• Golden DBK, et al. Anaphylaxis: A 2023 practice parameter update.
• Dhami S, et al. Management of Refractory Anaphylaxis: An Overview of Current Guidelines.
• Related training: EMS-MedSim.
• Global MedOps Command (main site).
• Books by Dr. Shermer.