Metronidazole 400 mg tablets are indicated for the treatment of various anaerobic bacterial infections and protozoal infections, contraindicated in patients with a history of hypersensitivity to metronidazole or other nitroimidazole derivatives, may cause side effects such as nausea, headache, and dizziness, and can interact with alcohol, leading to a disulfiram-like reaction, as well as with anticoagulants and other medications metabolized by the liver.