Oral Cephalosporin-Induced Anaphylaxis Presenting With Severe Tachycardia: A Case of Microdosed Epinephrine Over Standard Protocols

Anaphylaxis is a severe, rapidly progressing hypersensitivity reaction that requires prompt recognition and administration of intramuscular epinephrine. While guidelines recommend fixed-dose intramuscular epinephrine regardless of heart rate or blood pressure, there are situations where this approach may carry risks. We present the case of a 27-year-old patient with no prior comorbidities, including asthma, allergies, or cardiovascular conditions, who developed sudden breathlessness, generalized urticaria, and swelling of the face and lips shortly after taking oral cefpodoxime, a third-generation cephalosporin, prescribed for a febrile illness at a local hospital. On arrival at our hospital, the patient was conscious and alert, with an oxygen saturation of 87% on room air, a heart rate of 169 beats per minute, and a blood pressure of 100/60 mmHg. The ABCDE (Airway, Breathing, Circulation, Disability, Exposure) protocol was followed, and supportive care including oxygen, nebulized bronchodilators, and intravenous fluids was provided. Given the clear signs of anaphylaxis with marked tachycardia but no hypotension, there was a dilemma regarding the administration of standard intramuscular epinephrine due to concerns about worsening tachyarrhythmias. Under close monitoring, carefully titrated microdosed intravenous epinephrine was administered using a dilution protocol, resulting in rapid symptom improvement without cardiovascular instability. The patient was admitted to the intensive care unit for monitoring and supportive care and was later discharged in stable condition with oral antihistamines, corticosteroids, and clear instructions on allergen avoidance to prevent future emergencies. This case illustrates the need for clinical judgment when strict adherence to guidelines may pose a risk and demonstrates the role of individualized microdosed intravenous epinephrine in managing anaphylaxis in patients with significant tachycardia and normotension.