Treatment of Anaphylaxis: ABC
Remember the mnemonic ABC.
A: Adrenalin (epinephrine)
Epinephrine is the recommended drug for treating anaphylaxis. It works by stimulating alpha- and beta-adrenergic receptors to inhibit mediator release by both mast cells and basophils. Use of epinephrine at onset of symptoms inhibits the release of PAF, which is largely response for the life-threatening manifestations of anaphylaxis.
B: Benadryl (diphenhydramine)
Antihistamines will NOT stop anaphylaxis. They help to manage the symptoms experienced subsequent to the reaction.
C: Corticosteroids (hydrocortisone, prednisone, etc)
Corticosteroids will NOT stop anaphylaxis. It can decrease risk of biphasic or protracted anaphylaxis.
Standard treatment for anaphylaxis
- Epinephrine
- Airway maintenance.
- Oxygen, 6-8L/min.
- IV hydration. 25-50 ml/kg of lactated Ringer’s solution or normal saline.
Treatment of anaphylaxis in mast cell patients
- 0.3ml of 1:1000 diluted epinephrine, repeated 3x at five minute intervals if BP is less than 90 systolic (0.1ml for children under 12)
- Diphenhydramine 25-50mg (12.5-25mg for children under 12) orally, intramuscularly or intravenously (slow push) every 2-4 hours; or hydroxyzine 25mg (12.5mg for children ages 2-12) orally every 2-4 hours
- Methylprednisolone 120mg (40mg for children under twelve), intramuscularly or intravenously
- 100% oxygen by mask or nasal cannula
- Nebulized albuterol
Reference:
Emergency Room Response Plan. The Mastocytosis Society. Recommended by Dr. Mariana Castells.
Other treatment options
- Diphenhydramine 50mg or more in divided doses, oral or IV. Maximum dose is reported as 300mg (5mg/kg) for kids and 400mg for adults (under supervision.)
- Ranitidine 50mg in adults, 12.5-50 mg (1mg/kg for kids), administered by IV as 5% solution, total of 20ml, over five minutes.
- Albuterol 2.5-5 mg nebulized in 3ml normal saline, or levalbuterol 0.63-1.25 mg nebulized in 3ml normal saline as needed.
- Aminophylline, IV loading dose 5-6 mg/kg over 20 minutes, followed by IV infusion, 0.5-0.9 mg/kg/hr. Useful for persistent bronchospasm.
- For persistently low blood pressure, consider dopamine 400mg in 500ml, intravenously at dose of 2-20 mcg/kg/min.
- Glucagon 1-5mg (20-30mcg/kg, max of 1mg for kids) intravenously over five minutes, followed by IV infusion of 5-15 mcg/min.
- Methylprednisolone 1-2 mg/kg/24 hours.
- Sodium bicarbonate, 0.5-1 mEq/kg every five minutes as determined by arterial blood gases. Useful for persistent low blood pressure or acidemia.
- Methoxamine 10mg has been reported as working following failure of epinephrine. Has been suggested as a next-line medication following failure of second dose of epinephrine; has not seen much use.
References:
Higgins DJ and P Gayatri. Methoxamine in the management of severe anaphylaxis. Anesthesia 1999: 54(11), 1126.
Neugut et al. Arch Int Med 2001
Yocum et al. J Allergy Clin Immunol 1999
Sampson H. N Engl J Med 2002
Sampson et al. J Allergy Clin Immunol 2006
Sheikh et al. BMJ 2006
Kemp SF and Lockey JACI 2002; 110:341-8