The nizonide 500mg Tablet contains nitazoxanide, an antiparasitic medication used to treat infections caused by protozoa and certain parasites. It is commonly prescribed for conditions like diarrhea caused by Giardia lamblia or Cryptosporidium parvum, which can lead to gastrointestinal symptoms. Nizonide works by interfering with the energy production of parasites, causing their death and clearing the infection. It is generally well-tolerated but may cause side effects like nausea, abdominal pain, or headaches. Nizonide should be taken as directed by a healthcare provider, typically with food to improve absorption and reduce stomach discomfort.