Ondansetron and loss of appetite. taking ondansetron (zofran) for one week. when does appetite return?

The time for 1/2 the drug to leave your body is~ 4 hrs and by 16 hrs it should be gone, eliminated through liver metabolism. If the lack of appetite is due to the drug, and not the condition causing you to use it, it should return the day after you stop it. If your liver is slow breaking it down, it may take longer.

Ondansetron is typically used for nausea/vomiting to alleviate symptoms and allow for work up to conclude. If your main symptom is appetite loss, work up is needed and ondansetron would not help as an appetite booster. Talk to your doc, monitor weight.