Comparative Pharmacology
Head-to-head clinical analysis: SULFISOXAZOLE DIOLAMINE versus TRIMETH SULFA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULFISOXAZOLE DIOLAMINE versus TRIMETH SULFA.
SULFISOXAZOLE DIOLAMINE vs TRIMETH/SULFA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sulfisoxazole diolamine is a sulfonamide antibiotic that competitively inhibits dihydropteroate synthase, blocking the conversion of p-aminobenzoic acid (PABA) to dihydropteroic acid, thereby inhibiting bacterial folate synthesis and nucleic acid production.
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 orally initially, followed by 4-8 g/day in 4-6 divided doses for urinary tract infections; 6-8 g/day in 4-6 divided doses for nocardiosis.
1 double-strength tablet (160 mg trimethoprim / 800 mg sulfamethoxazole) orally every 12 hours for 14 days.
None Documented
None Documented
5-10 hours (prolonged in renal impairment; normal half-life in adults ~6 hours)
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: 70-100% (primarily as unchanged drug and acetylated metabolite); 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 C
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic