Nitazoxanide 500 mg an antiparasitic and antiviral medication, typically starts working within a few days of administration. Its onset of action varies depending on the specific infection being treated. In cases of intestinal parasitic infections, symptomatic relief may be noticeable relatively quickly as the medication targets the parasites. For viral infections, such as certain respiratory conditions, the antiviral properties of Nizonide 500 may take some time to exhibit noticeable effects. It's essential to complete the prescribed course to ensure the eradication of the infection fully. Individual responses can vary, and patients should follow healthcare professionals' guidance for optimal results.