Severe allergic reaction refers to the sudden, serious, life-threatening systemic allergic reaction of the body after contact with allergens, and untimely diagnosis and improper treatment can lead to serious consequences. The use of emergency drugs for severe allergic reactions is a crucial step, and each step in the selection of emergency drugs, timing of administration, dose and route of administration is critical, and then start with a case.
Case[1]
Patient, female, 48 years old.
Cefoperazone/sulbactam sodium 3 g + 0.9% sodium chloride injection 250 mL intravenously was given due to bronchial inflammation on chest radiograph.
After about 10 minutes of infusion, the patient has difficulty breathing, cyanosis of the lips, unmeasured blood pressure, lost pulse, loss of consciousness, etc.
Discontinue immediately, give oxygen, epinephrine 1.5 mg intramuscularly, dexamethasone 10 mg slowly intravenously, and 10% calcium gluconate plus 5% glucose injection 250 mL intravenous drip.
Finally, he died after ineffective rescue.
In this case, there were three problems with the rescue plan:
1. The dose of epinephrine hydrochloride injection is too large;
2. 10% calcium gluconate is not suitable for the rescue of anaphylactic shock;
3. Glucocorticoid selection of dexamethasone is not suitable.
Rescue process for allergic reactions
Source: References [2]
Common medication misunderstandings for severe allergic reactions
In the rescue of severe allergic reactions in China, there are three major medication errors:
× Subcutaneous injection of epinephrine, excessive dose.
× corticosteroids as the drug of choice.
× Intravenously or drip 10% calcium gluconate injection.
How to rationally use drugs for anti-anaphylactic shock
1. Epinephrine [3]
1. Timing of administration of epinephrine
Epinephrine is the drug of choice for anaphylactic shock rescue and should be used as soon as possible when anaphylaxis is diagnosed with grade II or above.
The grading criteria for severe allergic reactions are shown in the following table:
2. The route of administration and dosage of epinephrine
Discussion: In the above case, epinephrine was injected intramuscularly at an excessive dose. If used in excess, it may cause blood pressure, myocardial ischemia, and arrhythmias; Symptoms such as brief pallor, palpitation, and headache may also occur. Even in CPR, high doses of epinephrine are no longer recommended because they are not conducive to long-term survival.
Second, glucocorticoids[3, 4]
Glucocorticoids (eg, intravenous hydrocortisone, methylprednisolone, or oral prednisone or prednisolone) may be used as second-line agents (first-line epinephrine) for anaphylactic shock, but their effects have not been demonstrated.
Oral or intravenous corticosteroids may reduce the risk of biphasic or delayed reactions. Early high-dose intravenous corticosteroids, such as hydrocortisone 200~300 mg/day or methylprednisolone 1~2 mg/day (kg·d), reduce the risk of delayed respiratory reactions, and should be discontinued after 1 or 2 days without tapering.
Discussion: Dexamethasone is not appropriate in the above cases. Because dexamethasone has a slow onset, dexamethasone should not be used in severe allergic reactions. If persistent bronchospasm develops, nebulized or intravenous corticosteroids may be considered, but glucocorticoids should not be used as first-line treatment for anaphylaxis.
III. Beta2 receptor agonists
Short-acting beta-2 agonists can be used as a second-line agent for the treatment of anaphylaxis, and short-acting beta-2 agonists can be inhaled in patients with bronchospasm, dyspnea, and stridor.
Commonly used short-acting beta-2 agonists
IV. Antihistamines[3]
H1 blockers can be used as second-line agents for the treatment of anaphylaxis, mainly for relieving mucosal symptoms, not as rescue drugs. Grade I reactions can be given orally, and patients with grade II reactions and above can be given orally or intravenously after epinephrine rescue. Intramuscular chlorpheniramine maleate injection, promethazine injection, and diphenhydramine injection are not the first treatment.
Commonly used antihistamines
5. 10% calcium gluconate[5]
Calcium gluconate has anti-inflammatory, swelling and allergy-relieving effects because it can increase the density of capillaries and reduce their permeability. It is widely used in acute and chronic urticaria, drug-induced rash, skin itching and other allergic skin diseases.
Calcium is the main regulatory medium of the central regulation point of body temperature, and also has a regulatory effect on peripheral blood vessels. In addition, calcium agents exert a competitive inhibitory effect on the blood flow of sodium in cardiomyocytes, causing various arrhythmias or cardiac arrest. High calcium is prone to dizziness, nausea, vomiting, chest tightness and other adverse reactions, and severe cases can cause ventricular fibrillation, severe atrioventricular block, etc. Therefore, calcium therapy is effective only in cases of hyperkalemia, hypocalcemia, or calcium-channel blocker poisoning, and calcium therapy is not used in other cases.
Discussion: Neither domestic nor foreign guidelines recommend calcium gluconate injection for the rescue of severe allergic reactions and cardiopulmonary resuscitation.
6. Hyperglycon
Severe allergic disease may be effective in patients who do not respond to epinephrine, particularly those on β-blockers.
7. Fluid resuscitation
Fluid resuscitation can be used in patients with severe allergic reactions and circulatory instability, typically 20 mL/kg, adjusted according to the patient.
This article was first published on Lilac Garden's professional platform: Clinical Medication Guidelines for Lilac Garden
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[1] GAO Ling, YANG Xiaoqing. Death from anaphylactic shock caused by intravenous infusion of cefoperazone/sulbactam sodium[J]. Journal of Adverse Drug Reactions,2008,10(6):445-446.
[2] Muraro A, Worm M, Alviani C, et al. EAACI guidelines: Anaphylaxis (2021 update). Allergy. 2022. 77(2): 357-377.
[3] Li Xiaotong, et al. Recommendations of "First Aid Guidelines for Severe Allergic Reactions"[J]. Journal of Adverse Drug Reactions,2019,21(2):85-91.
[4] Consensus Expert Group on Emergency Use of Glucocorticoids. Expert consensus on emergency application of glucocorticoids [J]. Chinese Journal of Emergency Medicine,2020,29(6):765-772.
[5] Cai Shuzhen. Rescue and nursing of cardiac arrest caused by intravenous calcium gluconate[J]. Jiangsu Health Care,2007,9(2):11.