Diazepam is a benzodiazepine (ben-zoe-dye-AZE-eh-peens). Diazepam affects chemicals in the brain that may become unbalanced and cause anxiety. Diazepam is used to treat anxiety disorders, alcohol withdrawal symptoms, or muscle spasms. Diazepam is sometimes used with other medications to treat seizures. Diazepam may also be used for purposes not listed in this medication guide. round, blue, imprinted with barr, 555 164. round, blue, imprinted with Z 3927, 10.