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.