Anaphylaxis Medication Protocol

Anaphylaxis is a rapid, life-threatening allergic reaction with airway, breathing or circulation problems, usually with skin or mucosal signs. Adrenaline given intramuscularly without delay is the key treatment, and no other drug replaces it.

Diagnosis. Sudden onset after exposure with airway swelling, wheeze, stridor, hypotension or collapse, with or without urticaria. Skin signs may be absent.

Triggers. Foods, drugs (beta-lactams, NSAIDs, neuromuscular blockers), insect stings, latex, and contrast media.

First line. Adrenaline 1 mg/mL (1 in 1000) intramuscularly into the anterolateral thigh.

Alongside. Lie the patient flat with legs raised (or sitting if breathless, left lateral in pregnancy), give high-flow oxygen and rapid intravenous fluid.

Adjuncts only after adrenaline. Nebulised salbutamol for wheeze, chlorphenamine and a corticosteroid for skin symptoms. They do not treat shock.

Refractory. Adrenaline infusion. Glucagon for patients taking beta blockers.

Special groups.

• Children: weight-based adrenaline, and fluid 20 mL/kg.

• Pregnancy: adrenaline is used at the usual adult dose, with left lateral tilt.

• Beta blocker or ACE inhibitor users: reactions can be more severe and resistant.

• East Africa: stings, bites, food and drug reactions are all possible, so check that the ampoule is 1 mg/mL before drawing up, as other strengths exist.

• Adrenaline intramuscular: 0.5 mg (0.5 mL of 1 mg/mL) in adults, repeated every 5 minutes if no improvement. Children 0.01 mg/kg (maximum 0.5 mg).

• Adrenaline infusion (refractory): 0.05 to 0.5 micrograms/kg/min intravenously, with monitoring.

• Fluid: 500 to 1000 mL of crystalloid rapidly in adults, 20 mL/kg in children, repeated as needed.

• Salbutamol: 5 mg nebulised, repeated.

• Chlorphenamine: 10 mg intravenously or intramuscularly in adults, after resuscitation.

• Hydrocortisone: 200 mg intravenously for severe or asthmatic reactions.

• Glucagon: 1 to 5 mg intravenously over 5 minutes, then 5 to 15 micrograms/min for beta blocker users.

Monitoring. Continuous ECG, oximetry and blood pressure. Take serum tryptase within 1 to 2 hours of onset and again at 24 hours. Observe for at least 6 hours, and for 12 hours after a severe reaction or when adrenaline was repeated, because of biphasic reactions.

Stop rules. Stop the trigger (drug infusion, contrast, transfusion) at once.

Referral and escalation. Seek intensive care for airway compromise, refractory shock or two or more adrenaline doses. Refer to allergy services, supply two adrenaline auto-injectors with training, and write a plan.

Common errors. Delaying adrenaline, using the subcutaneous or intravenous bolus route, relying on antihistamines or steroids, and discharging early.