Comparative Pharmacology
Head-to-head clinical analysis: SULFADIAZINE versus TRIMETH SULFA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULFADIAZINE versus TRIMETH SULFA.
SULFADIAZINE vs TRIMETH/SULFA
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.
Trimethoprim inhibits bacterial dihydrofolate reductase (DHFR), blocking conversion of dihydrofolate to tetrahydrofolate; sulfamethoxazole inhibits bacterial dihydropteroate synthase, blocking incorporation of para-aminobenzoic acid into folic acid. Sequential blockade of folate synthesis produces synergistic bactericidal effect.
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.
1 double-strength tablet (160 mg trimethoprim / 800 mg sulfamethoxazole) orally every 12 hours for 14 days.
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: 8-11 hours; Sulfamethoxazole: 9-11 hours. Prolonged in renal impairment (up to 24-30 hours for both). Clinical context: Dosing interval is typically 12 hours in normal renal function; adjust in CrCl <15-30 mL/min.
Renal excretion of unchanged drug (50-70%) and acetylated metabolites; minor biliary/fecal (<5%)
Trimethoprim: 50-60% unchanged in urine; Sulfamethoxazole: 15-30% unchanged in urine, with acetylation and glucuronidation metabolites. Approximately 80-90% of dose recovered in urine within 72 hours; remainder via feces.
Category D/X
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic