Analgin Injection, containing Metamizole Sodium, is a pyrazolone-class drug for emergency fever reduction and acute pain relief via intramuscular injection. However, due to serious risks like agranulocytosis and organ damage, its use has declined. Adult dose: 0.25-0.5g (≤1.8g/day); pediatric dose: 5-10mg/kg. Contraindicated in allergic individuals, pregnant women, and newborns. Safer alternatives like paracetamol are now preferred.