Niftas 50 Tablet is an antibiotic that fights bacteria It is used to treat and prevent bacterial infections of the urinary tract It works by killing the bacteria that cause such disease But it will not treat a viral infection Niftas 50 Tablet should be taken in the dose and duration as advised by the doctor You may take it with food to avoid Nausea which is a common side effect It is better to have this medicine at the same time each day to get the most benefit and you should keep on taking this medicine for as long as you are prescribed it even if your symptoms quickly improve If you stop taking it too early the infection may return or worsen Some people may develop side effects like Nausea vomiting and diarrhea These side effects are usually temporary and go away during treatment as your body adjusts to the medicine Consult your doctor if these side effects bother you or do not go away This medicine may turn your urine into dark yellow or brown color But this is normal and nothing to worry about