Sulfadiazine sodium ose vaila'au sulfonamide medium-acting e iai a'afiaga fa'ama'i i le tele o siama Gram-positive ma Gram-negative. E iai aʻafiaga faʻamaʻi i luga ole Staphylococcus aureus e le gaosia, Streptococcus pyogenes, Streptococcus pneumoniae, Escherichia coli, Klebsiella, Salmonella, Shigella, Neisseria gonorrhoeae, Neisseria meningitidis, ma le Haemophilus influenzae. E le gata i lea, e malosi foi e faasaga ia Chlamydia trachomatis, Nocardia asteroides, Plasmodium, ma Toxoplasma in vitro. Ole gaioiga antibacterial o lenei oloa e tutusa ma le sulfamethoxazole. Ae ui i lea, i tausaga talu ai nei, ua faateleina le tetee o siama i lenei oloa, aemaise lava Streptococcus, Neisseria, ma Enterobacteriaceae.