A client with terminal cancer reports increasing pain that occurs 1 to 2 hours before the next scheduled dose of a prescribed opioid analgesic. Which action should the practical nurse (PN) implement?

Choice A reason: Cephalexin, a cephalosporin, has a 5–10% cross-reactivity risk with penicillin allergies due to similar beta-lactam structures. An anaphylactic history increases the risk of severe reactions. Contacting the provider ensures safety, potentially leading to an alternative antibiotic to prevent life-threatening allergic responses.

Choice B reason: Monitoring for rash or hives is reactive and insufficient for a client with a penicillin anaphylaxis history. Cephalexin’s cross-reactivity risk requires proactive avoidance, not just observation, as anaphylaxis can occur rapidly, making this choice inadequate compared to provider consultation.

Choice C reason: Giving cephalexin with an antihistamine does not prevent anaphylaxis, which can be rapid and severe in penicillin-allergic clients. Antihistamines mitigate mild allergies but are ineffective against severe reactions. This choice is unsafe without confirming the drug’s appropriateness first.

Choice D reason: Administering cephalexin as prescribed ignores the significant risk of cross-reactivity with penicillin, given the client’s anaphylactic history. This could trigger a life-threatening reaction, as cephalosporins share structural similarities with penicillins, making immediate administration without verification dangerous.

Choice A reason: Taking medications with food may reduce gastric irritation but does not prevent anaphylactic reactions to penicillin, which are immune-mediated. This advice is irrelevant for avoiding future allergic responses, as it does not address the systemic hypersensitivity triggered by penicillin exposure.

Choice B reason: A medic alert bracelet is critical for a client with a penicillin anaphylaxis history, as it alerts healthcare providers to avoid penicillin, preventing potentially fatal allergic reactions. Anaphylaxis involves IgE-mediated histamine release, and re-exposure risks rapid, life-threatening symptoms, making this the most important instruction.

Choice C reason: Keeping epinephrine is useful for managing anaphylaxis but is secondary to prevention. A medic alert bracelet proactively avoids penicillin exposure, reducing the need for emergency intervention. Epinephrine treats symptoms but does not address the root cause of re-exposure risk.

Choice D reason: Taking all prescribed ampicillin is dangerous, as the client had an anaphylactic reaction, indicating a severe allergy. Continuing the drug risks recurrent, potentially fatal reactions. This choice is incorrect, as it contradicts the need to avoid the allergen entirely.