A patient who is prescribed a medication with a short onset of action experiences a rapid and unexpected adverse reaction resulting in facial swelling and difficulty breathing. Which action should the nurse take first?

A. Document the adverse reaction in the patient’s chart: Documentation is important for legal and clinical records but is not the immediate priority in a life-threatening situation. Patient safety comes first. B. Assess the patient's airway, breathing, and circulation: Facial swelling and difficulty breathing indicate a potential anaphylactic reaction, which can be rapidly fatal. The nurse must first assess and maintain airway patency, oxygenation, and circulation before taking other actions. C. Notify the provider immediately: Notifying the provider is necessary, but the nurse must first ensure the patient’s airway and vital functions are stable. Immediate intervention can be lifesaving. D. Administer another dose of the medication to counteract the adverse reaction: Administering another dose would worsen the reaction. The priority is halting exposure and initiating emergency treatment, such as epinephrine if indicated.