MS-1900

A 20-year-old man presents to the emergency department with difficulty breathing and swollen lips following a wasp sting. His vital signs are as follows:

Heart rate: 120 bpm
Blood pressure: 105/65 mmHg
Respiratory rate: 30 per minute
SpO2: 92%
Temperature: 36.9ºC

What is the immediate treatment that should be administered based on the probable diagnosis?