A client is receiving metronidazole for Clostridium difficile pseudomembranous colitis. Which information should the nurse include in this client's medication teaching plan?

A. Avoid the use of alcohol: Metronidazole can cause a disulfiram-like reaction when combined with alcohol, leading to severe nausea, vomiting, flushing, tachycardia, and hypotension. Clients must be strictly advised to avoid all forms of alcohol, including hidden sources like cough syrups, during treatment and for at least 48 hours after completing therapy. B. Drink a liter of water daily: While staying hydrated is generally good for overall health, it's not a specific requirement directly related to the action or side effects of metronidazole for C. difficile colitis. Maintaining adequate fluid intake is important for managing diarrhea associated with the infection, but it's not a direct instruction tied to the medication itself. C. Keep medication refrigerated: Metronidazole tablets or oral suspension do not require refrigeration; they should be stored at room temperature. Refrigeration is not necessary and could even alter the medication’s consistency or effectiveness. D. Take one hour after eating: Metronidazole is generally better tolerated when taken with food to minimize gastrointestinal upset. Advising clients to take it after eating can help but is not mandatory nor the most crucial teaching point compared to alcohol avoidance.