Comparative Pharmacology
Head-to-head clinical analysis: GANTRISIN PEDIATRIC versus TRIMETH SULFA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GANTRISIN PEDIATRIC versus TRIMETH SULFA.
GANTRISIN PEDIATRIC vs TRIMETH/SULFA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sulfisoxazole is a competitive inhibitor of bacterial dihydropteroate synthase, preventing the incorporation of para-aminobenzoic acid (PABA) into dihydrofolate, thereby inhibiting bacterial folic acid synthesis.
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.
2-4 g initially, then 4-6 g/day in 3-6 divided doses orally, depending on severity. Alternatively, for sulfisoxazole (the active moiety), typical adult dose is 500 mg to 1 g orally every 6 hours. IM use: 50 mg/kg initially, then 100 mg/kg/day in divided doses every 6-8 hours. IV use: Not recommended in pediatric formulation.
1 double-strength tablet (160 mg trimethoprim / 800 mg sulfamethoxazole) orally every 12 hours for 14 days.
None Documented
None Documented
Terminal elimination half-life is 6-12 hours (prolonged in renal impairment; up to 30 hours in patients with creatinine clearance <10 mL/min).
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.
Primarily renal (70-100% as unchanged drug and acetylated metabolites) via glomerular filtration and tubular secretion; <10% fecal.
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 C
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic