Comparative Pharmacology
Head-to-head clinical analysis: SULSTER versus TRIMETH SULFA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULSTER versus TRIMETH SULFA.
SULSTER vs TRIMETH/SULFA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sulster is a sulfonamide antibiotic that inhibits bacterial dihydropteroate synthase, blocking folate synthesis and thus bacterial DNA replication.
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.
2.5 mg orally twice daily.
1 double-strength tablet (160 mg trimethoprim / 800 mg sulfamethoxazole) orally every 12 hours for 14 days.
None Documented
None Documented
Terminal half-life 3.5-4.5 hours in normal renal function; prolonged to 10-15 hours with creatinine clearance <30 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 (60-70% unchanged), with 20-30% as glucuronide conjugate; biliary/fecal <10%.
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