What is the correct initial action the nurse should take regarding the ceftriaxone allergy?

The initial action a nurse should take regarding a ceftriaxone allergy is to notify the physician of the allergy. This step is crucial because it ensures that the physician is aware of the patient's allergic reaction, enabling them to make informed decisions regarding treatment options. Addressing allergies is a fundamental aspect of patient safety, as it directly influences the choice of medications prescribed.

By alerting the physician, the nurse facilitates the evaluation of alternative treatment plans that do not involve ceftriaxone or any related drugs, thus avoiding potential adverse reactions. This proactive communication helps in establishing a comprehensive care plan that prioritizes the patient's well-being.

The other options, while relevant to managing allergies, do not take precedence in this situation. Administering the medication with additional monitoring could expose the patient to unnecessary risk, while documenting the allergy is important but should follow the immediate communication with the physician to prevent any prescriptions that may cause harm. Asking the client to sign an allergy waiver is not a standard practice and can be unethical, as it may put the patient's safety at risk if they are pressured to accept a medication that could trigger a severe reaction. Thus, notifying the physician is the most critical initial action in managing the allergy.