Comparative Pharmacology
Head-to-head clinical analysis: SULFADIAZINE versus TRIMETHOPRIM SULFAMETHOXAZOLE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULFADIAZINE versus TRIMETHOPRIM SULFAMETHOXAZOLE.
SULFADIAZINE vs Trimethoprim-Sulfamethoxazole
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Competitive inhibitor of dihydropteroate synthase, blocking the synthesis of folic acid in bacteria.
Sulfamethoxazole inhibits dihydropteroate synthase, blocking para-aminobenzoic acid incorporation into dihydrofolate; trimethoprim inhibits dihydrofolate reductase, preventing tetrahydrofolate formation. Sequential blockade of folate synthesis.
Oral: 2-4 g initially, then 1 g every 4-6 hours for mild to moderate infections; for severe infections, 4 g initially followed by 1.5 g every 4 hours. IV: Not available in IV form in the US; if using oral suspension, adjust accordingly.
Oral: 160 mg TMP/800 mg SMX every 12 hours; IV: 8-10 mg/kg/day (based on TMP) in 2-4 divided doses
None Documented
None Documented
Clinical Note
moderateSulfadiazine + Gatifloxacin
"Sulfadiazine may increase the hypoglycemic activities of Gatifloxacin."
Clinical Note
moderateSulfadiazine + Rosoxacin
"Sulfadiazine may increase the hypoglycemic activities of Rosoxacin."
Clinical Note
moderateSulfadiazine + Levofloxacin
"Sulfadiazine may increase the hypoglycemic activities of Levofloxacin."
Clinical Note
moderateSulfadiazine + Trovafloxacin
"Sulfadiazine may increase the hypoglycemic activities of Trovafloxacin."
Terminal elimination half-life 10-20 hours (prolonged in renal impairment; may require dose adjustment)
Trimethoprim: 8-10 hours (normal renal function); prolonged to 24-30 hours in severe renal impairment (CrCl <10 mL/min). Sulfamethoxazole: 9-11 hours; prolonged in renal failure. The combination retains a half-life of ~10-12 hours in healthy adults, requiring dose adjustment in renal impairment.
Renal excretion of unchanged drug (50-70%) and acetylated metabolites; minor biliary/fecal (<5%)
Trimethoprim: 50-60% excreted unchanged in urine via glomerular filtration and tubular secretion; 10-20% as metabolites. Sulfamethoxazole: 20-30% excreted unchanged in urine; 50-70% as N4-acetylated metabolite. Both undergo minimal biliary/fecal elimination (<5% total).
Category D/X
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic