Synonyms: Pyrazinobutazone;1,2-Diphenyl-3,5-dioxo-4-n-butylpyrrazolidine de piperazine;1,2-Diphenyl-3,5-dioxo-4-n-butylpyrrazolidine de piperazine [French];4-Butyl-1,2-diphenyl-3,5-pyrazolidinedione compd. with piperazine (1:1);Carudol;DB 139;Pyrasanone;Ranoroc;3,5-Pyrazolidinedione, 4-butyl-1,2-diphenyl-, compd. with piperazine (1:1);4-Butyl-1,2-diphenylpyrazolidine-3,5-dione, compound with piperazine (1:1);4-butyl-1,2-diphenylpyrazolidine-3,5-dione - piperazine (1:1)