Sulfonamides  (PDF Version)


Antibiotic Class:

Sulfonilamide (parent compound of sulfonamides)


Antimicrobial Spectrum:

Staphylococcus aureus, Coagulase negative Staphylococci, Streptococcus spp., Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrhoeae, Enterobacteriaceae, E. coli, Nocardia spp., Stenotrophomonas, Burkholderia Mycobacteria (non-tuberculosis spp.)


Mechanism of Action:

Sulfonamides compete for PABA in the bacterial pathway responsible for DNA synthesis



No data



Cmax: 15-200 mcg/L (range); Half-life: Typically 4-16h; Protein binding: 25% to 95%; Table 1


Adverse Effects:

Skin: Rash, toxic epidermal necrolysis, Stevens-Johnson syndrome

Hematologic: Agranulocytosis

GI: Diarrhea

Renal: Interstitial nephritis

Other: Fever



Variable by sulfonamide, Table 1


Disease state based dosing:

Variable by sulfonamide



Warning: Will cause hemolytic anemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Usually occurs in first week of therapy. May potentiate the action of concomitantly administered drugs (see Drug Interactions section)


Drug Interactions:

Sulfonamides may potentiate the effects of drugs such as warfarin, sulfonylurea hypoglycemic agents, phenytoin, and methotrexate



Category B: No evidence of risk in humans but studies inadequate.


Monitoring Requirements:

Therapeutic: Culture and sensitivities, serum levels, signs and symptoms of infection, white blood cell count

Toxic: Urinalysis, BUN, SCr, Skin manifestations of any type, complete white blood cell count,


Brand names/Manufacturer:  Various generic manufacturers