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Introduction

Anaphylaxis is a severe, potentially life-threatening systemic hypersensitivity reaction. First-line therapy remains IM epinephrine 0.3-0.5 mg in the anterolateral mid-thigh, repeated every 5-15 minutes as needed.1

Refractory anaphylaxis is persistent symptoms or hemodynamic instability despite 2-3 appropriate IM epinephrine doses and adequate fluid resuscitation. Definitions vary, but the practical bedside signal is the same: repeated IM doses are no longer enough.

Key Points

  • Escalate to IV epinephrine infusion when shock persists after repeated IM epinephrine and fluids.
  • Aggressive crystalloid resuscitation is essential and commonly under-administered.
  • Avoid IV epinephrine bolus outside cardiac arrest because severe hypertension and arrhythmias are well described.
  • Use glucagon for beta-blocker-mediated refractory anaphylaxis; use norepinephrine or vasopressin when vasopressor support is still needed.

Pharmacology

AgentRoleAdult Dose
EpinephrinePrimary refractory strategy. Alpha-1 vasoconstriction, beta-1 inotropy/chronotropy, beta-2 bronchodilation and mast-cell stabilization.IM 0.3-0.5 mg q5-15 min initially. IV infusion 0.05-0.5 mcg/kg/min titrated to MAP and clinical response.
GlucagonAdjunct for patients on beta-blockers with inadequate epinephrine response; bypasses beta-receptor blockade through adenylyl cyclase activation.1-5 mg IV over 5 min, then 5-15 mcg/min infusion. Pretreat nausea/vomiting when feasible.
NorepinephrineMost commonly used second-line vasopressor when epinephrine infusion and fluids do not restore perfusion.0.05-1 mcg/kg/min, titrated to MAP. Central access preferred, but do not delay in extremis.
VasopressinAlternative/add-on for vasoplegic shock when catecholamine response remains inadequate.0.01-0.04 units/min.
Methylene blueAdjunct (not replacement) for catecholamine-resistant vasoplegic shock. Inhibits the nitric oxide–cGMP/guanylate-cyclase pathway, countering pathologic vasodilation. Case-report–level evidence; named in few guidelines.1-2 mg/kg IV over 5-10 min. Caution in G6PD deficiency and with serotonergic agents.
ECMO / ECLSVA-ECMO as a last-line salvage for epinephrine-refractory cardiovascular collapse or arrest, supporting circulation while the reaction resolves. Repeated neuro-intact survival in case reports — activate early rather than after prolonged arrest.Institution-specific; mobilize the ECMO/cardiac-surgery team as soon as refractory collapse is recognized.

Clinical Pearl

The key switch is not from IM epinephrine to IV epinephrine bolus. It is from repeated IM epinephrine to a carefully titrated IV epinephrine infusion with aggressive fluids.

Key Evidence

SourceEvidence TypePractical Takeaway
Brown 20045Prospective observational study in insect sting anaphylaxis.IV bolus epinephrine was associated with arrhythmias or hypertensive emergencies in 57% of bolus-treated cases.
Francuzik 20188European registry/case-report review.Severe anaphylaxis is often undertreated with epinephrine; delayed escalation remains a systems problem.
Tacquard 20249International perioperative anaphylaxis work.Refractory anaphylaxis may occur in up to 12% of perioperative cases; norepinephrine is commonly added second line.
Pouessel 20242International guideline synthesis.Guidelines align on IV epinephrine infusion and fluids; comparative data for second-line vasopressors are lacking.
Wang 201711Pharmacovigilance analysis of epinephrine dosing.IV bolus dosing was overdosed far more often than IM (94% vs 57%), and most cardiovascular adverse events occurred in overdosed patients — favor a titrated infusion over repeat IV boluses.
Campbell 201512Emergency department cohort.About 8% of ED anaphylaxis patients needed a second epinephrine dose; needing a repeat dose marks more severe disease and predicts admission.

Second-Line & Rescue Therapy Evidence

Epinephrine infusion plus aggressive fluid resuscitation remains the backbone of refractory anaphylaxis. The therapies below are genuine rescue options, but the evidence base is almost entirely case reports and small series — they supplement, and never delay, a definitive epinephrine strategy.

Methylene blue

Targets the nitric oxide–cGMP pathway driving vasoplegia. Reported dose ~1–2 mg/kg IV; the best evidence supports it as an adjunct to epinephrine, not a substitute. Absent from most guidelines (Spain notes it “can be useful”; France does not recommend it).

StudyFinding
Evora & Simon 200713Human review/series of methylene blue for anaphylactic hypotension — the strongest human signal; consider when standard therapy fails.
Bauer 201214Refractory anaphylaxis without hypotension reversed by methylene blue; intubation avoided (single case).
Zheng 201315Controlled rat model: methylene blue added to epinephrine was synergistic on blood pressure and cardiac output and uniquely limited cerebral ischemia; methylene blue alone was insufficient.
Menardi 201116Negative pig model: methylene blue 2 mg/kg (plus 2.66 mg/kg/h) did not reverse the shock — included as an honest counterweight.

ECMO / extracorporeal life support

VA-ECMO can sustain circulation through epinephrine-refractory collapse or arrest until the reaction resolves. Case reports across drug, venom, and latex triggers show repeated neurologically intact survival — the recurring lesson is to involve the ECMO team early, before prolonged low-flow arrest.

CaseOutcome
Joseph 202218Anaphylactic arrest under anesthesia; ED-initiated VA-ECMO — survived, neurologically intact.
Carelli 201919Two rocuronium anaphylaxis cases supported with VA-ECMO — both neurologically intact.
Le 202321Bee-sting refractory anaphylactic shock rescued with VA-ECMO — survived, neurologically intact.
Grafeneder 202220Multiphasic, epinephrine-refractory anaphylaxis (underlying mastocytosis) supported on ECMO and weaned at 4 days.

Escalation Plan

Step 1

Confirm repeated IM epinephrine, airway/oxygen support, trigger removal, and rapid crystalloid resuscitation.

Step 2

Start IV epinephrine infusion 0.05-0.5 mcg/kg/min and titrate to perfusion, MAP, and respiratory response.

Step 3

Add glucagon for beta-blocker-mediated shock, norepinephrine or vasopressin for persistent vasoplegia, and rescue therapies only after standard escalation fails.

Pharmacist checkpoint

Prepare infusion concentrations early, clarify weight-based dosing, flag beta-blocker exposure, watch potassium/glucose/lactate, and keep sodium bicarbonate away from catecholamine Y-sites.

Clinical Conclusions

IV epinephrine infusion is the cornerstone. Refractory anaphylaxis should trigger infusion escalation rather than endless repeated IM dosing.

Avoid IV epinephrine bolus outside cardiac arrest. Observational data show high rates of serious cardiovascular adverse events with bolus dosing.

Glucagon is targeted, not routine. Reserve it for suspected beta-blocker-mediated refractory anaphylaxis and anticipate vomiting and hyperglycemia.

Second-line vasopressor choice is evidence-limited. Norepinephrine is commonly used; vasopressin, methylene blue, and ECMO/ECLS are selected for refractory vasoplegia or cardiovascular collapse.

Full Reference List

  1. Golden DBK, Wang J, Waserman S, et al. Anaphylaxis: A 2023 practice parameter update. Ann Allergy Asthma Immunol. 2024;132(2):124-176.
  2. Pouessel G, Dribin TE, Tacquard C, et al. Management of Refractory Anaphylaxis: An Overview of Current Guidelines. Clin Exp Allergy. 2024;54(7):470-488.
  3. Dribin TE, Waserman S, Turner PJ. Who Needs Epinephrine? Anaphylaxis, Autoinjectors, and Parachutes. J Allergy Clin Immunol Pract. 2023;11(4):1036-1046.
  4. Mink SN, Simons FER, Simons KJ, Becker AB, Duke K. Constant infusion of epinephrine, but not bolus treatment, improves haemodynamic recovery in anaphylactic shock in dogs. Clin Exp Allergy. 2004;34(11):1776-1783.
  5. Brown SGA, Blackman KE, Stenlake V, Heddle RJ. Insect sting anaphylaxis; prospective evaluation of treatment with intravenous adrenaline and volume resuscitation. J Allergy Clin Immunol. 2004;114(5):1044-1052.
  6. Brown SGA, Stone SF, Fatovich DM, et al. Anaphylaxis: clinical patterns, mediator release, and severity. J Allergy Clin Immunol. 2013;132(5):1141-1149.
  7. Thomas M, Crawford I. Best evidence topic report: glucagon infusion in refractory anaphylactic shock in patients on beta-blockers. Resuscitation. 2005;65(3):311-313.
  8. Francuzik W, Dolle S, Worm M. Risk factors and treatment of refractory anaphylaxis: a review of case reports. Allergy. 2018;73(5):1109-1112.
  9. Tacquard C, Iba T, Levy JH, et al. Refractory anaphylaxis: definition and management. Br J Anaesth. 2024;132(6):1217-1223.
  10. Cardona V, Ansotegui IJ, Ebisawa M, et al. World Allergy Organization Anaphylaxis Guidance 2020. World Allergy Organ J. 2020;13(10):100472.
  11. Wang T, Ma X, Xing Y, et al. Use of Epinephrine in Patients with Drug-Induced Anaphylaxis: An Analysis of the Beijing Pharmacovigilance Database. Int Arch Allergy Immunol. 2017;173(1):51-60.
  12. Campbell RL, Bashore CJ, Lee S, et al. Predictors of Repeat Epinephrine Administration for Emergency Department Patients with Anaphylaxis. J Allergy Clin Immunol Pract. 2015;3(4):576-584.
  13. Evora PRB, Simon MR. Role of nitric oxide production in anaphylaxis and its relevance for the treatment of anaphylactic hypotension with methylene blue. Ann Allergy Asthma Immunol. 2007;99(4):306-313.
  14. Bauer CS, Vadas P, Kelly KJ. Methylene blue for the treatment of refractory anaphylaxis without hypotension. Am J Emerg Med. 2013;31(1):264.e3-264.e5.
  15. Zheng F, Barthel G, Collange O, et al. Methylene blue and epinephrine: a synergetic association for anaphylactic shock treatment. Crit Care Med. 2013;41(1):195-204.
  16. Menardi AC, Capellini VK, Celotto AC, et al. Methylene blue administration in the compound 48/80-induced anaphylactic shock: hemodynamic study in pigs. Acta Cir Bras. 2011;26(6):481-489.
  17. Schummer C, Wirsing M, Schummer W. The pivotal role of vasopressin in refractory anaphylactic shock. Anesth Analg. 2008;107(2):620-624.
  18. Joseph J, Bellezzo J. Refractory Anaphylactic Shock Requiring Emergent Venoarterial Extracorporeal Membrane Oxygenation in the Emergency Department: A Case Report. J Emerg Nurs. 2022;48(6):626-630.
  19. Carelli M, Seco M, Forrest P, et al. Extracorporeal membrane oxygenation support in refractory perioperative anaphylactic shock to rocuronium: a report of two cases. Perfusion. 2019;34(8):717-720.
  20. Grafeneder J, Schoergenhofer C, Sigmund M, et al. Multi-phasic life-threatening anaphylaxis refractory to epinephrine managed by extracorporeal membrane oxygenation. Front Allergy. 2022;3:934436.
  21. Le HY, Tien ND, Son PN, et al. Extracorporeal membrane oxygenation support in refractory anaphylactic shock after bee stings: A case report. Perfusion. 2023;38(6):1308-1310.
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