How should the nurse respond when a parent expresses concern about administering mebendazole to a child for three weeks?

The most appropriate response in this situation is to confirm the length of the course of treatment with the health care provider. This response acknowledges the parent's concerns and emphasizes the importance of adhering to medical guidance. Mebendazole is typically used to treat various parasitic worm infections, and while it is generally considered safe and effective, the duration of treatment can vary based on the specific type of infection being treated and the child’s overall health.

By confirming the treatment plan with the health care provider, the nurse ensures that the parent receives accurate information tailored to their child's needs. This engagement can help alleviate the parent's concerns by providing clarity on the treatment protocol and reinforcing the role of the health care provider in making treatment decisions.

The other choices, while they may contribute to patient education, do not directly address the parent's specific concern about the duration of the treatment. Simply reassuring the parent without verification may not fully alleviate their worries. Suggesting dietary changes might not be relevant to the question at hand, as the primary focus should be on the medication regimen. Providing written instructions about timing and dosages would be useful but does not engage with the parent's expressed concern regarding the length of treatment. Thus, confirming with the health care provider is the most comprehensive and supportive response.