What should the nurse explain to a client experiencing diarrhea after starting mebendazole?

Mebendazole is an anthelmintic medication commonly used to treat various helminthic infections. When a client experiences diarrhea after starting this medication, it is important to understand the mechanisms involved.

The correct option indicates that diarrhea is likely a side effect of the medication itself. Mebendazole works by immobilizing and killing the parasites, and as the dying worms are expelled from the body, gastrointestinal disturbances such as diarrhea may occur. This side effect is fairly common and usually not a cause for alarm unless it becomes severe or persistent, in which case it would warrant seeking medical advice.

Understanding this helps reassure the client that while gastrointestinal symptoms can be uncomfortable, they are often a part of the process of eliminating the infection. If the diarrhea worsens, it can be a sign that further evaluation is necessary, but it does not inherently suggest that the medication is ineffective or that the action of the medication is causing harm.

The other choices would mislead the client regarding the typical response to treatment with mebendazole and could cause unnecessary concern or confusion.