Analgin drug is from the group of pyrazolones. It contains an active compound called metamizole. It works by reducing the pain and fever, used in the treatment of sever pain and severe stomach pain . Analgin is just one among many such drugs—sold in India, banned elsewhere. Thioridazin continues to be available in India but also banned in US because its side effect causes eye damage,arrhythmia and neuroleptic malignant syndrome where the patient suffers from high temperature and muscle rigidity. There are many other like Disprin, Propoxyphene (Opioid Painkiller) that are available in India but banned in US.