Diazepam is a drug best known by the brand name Valium®. Diazepam is mostly used to treat anxiety, insomnia, seizures, muscle spasms, restless leg syndrome and symptoms of alcohol and benzodiazepine withdrawal.Other uses of valium include inducing amnesia and reducing tension during surgical procedures and as pre-medication for endoscopies.iazepam is mostly used to treat anxiety, insomnia, seizures, muscle spasms, restless leg syndrome and symptoms of alcohol and benzodiazepine withdrawal.