Analgin belongs to pyrazolone antipyretic and analgesic drugs. An Naijin tablet is a combination of aminopyrine and sodium sulfite, which is easily soluble in water and has obvious antipyretic effect and strong analgesic effect. It is mainly used to reduce fever during acute high fever, and can be used for short-term treatment of acute pain, such as headache, migraine, muscle pain, joint pain and dysmenorrhea.