In most species, members of this large group are administered 1-4 times/day, depending on the drug, to control systemic infections caused by susceptible bacteria. In some instances, administration of the sulfonamide can be less frequent if the drug is eliminated slowly in the species being treated. Sulfonamides included in this class, depending on the species, are sulfathiazole, sulfamethazine (sulfadimidine), sulfamerazine, sulfadiazine, sulfapyridine, sulfabromomethazine, sulfaethoxypyridazine, sulfamethoxypyridazine, sulfadimethoxine, and sulfachlorpyri-dazine.