Anaphylaxis emergency treatment in a pre-hospital setting:
Use emergency adrenaline auto-injector (a.k.a. brand name EpiPen) and go immediately to a hospital emergency room.
Avoid triggers: remove trigger or remove self from triggers.
Administer extra doses of H1 and H2 blockers e.g. ranitidine/cimetidine + fexofenadine/hydroxyzine/diphenhydramine.
Administer corticosteroids because these may prevent prolonged anaphylaxis treatment.
Treat H1 reactions (skin and respiratory: mucous overproduction, asthma, throat tightening, skin itching). Stop asthma attack: albuterol sulfate, cromolyn sodium nebulized and/or inhaled. Stop cough: cough drops. Clean up mucus: guaifenesin.
Treat H2 reactions (GI and cardiac: sudden diarrhea, gas, bloating, vomiting, nausea, low blood pressure, heart palpitations, difficulty breathing, feels like you may pass out): Stop H2 reaction: activated charcoal, cholestyramine, bland food to soak up the irritant and prevent new reactions. Nausea: sea bands. Cardiac symptoms including low blood pressure: electrolytes and fluids, lay down, assess severity.
Manage H3 reactions (neurological: confusion, motor control loss, fatigue, migraine, depression). Reduce likelihood of secondary injury: rest, lay down, do not drive, do not operate heavy machinery. Reduce triggers: breathe clean fresh air; retreat to safe room or environmental containment unit.