Comparative Pharmacology
Head-to-head clinical analysis: TERFONYL versus TRIMETH SULFA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: TERFONYL versus TRIMETH SULFA.
TERFONYL vs TRIMETH/SULFA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
TERFONYL is a sulfonamide antibiotic that inhibits bacterial dihydropteroate synthase, thereby blocking folate synthesis and 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 g intravenously every 12 hours over 24 hours for susceptible infections.
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 2.5-4 hours in adults with normal renal function; prolonged to 12-24 hours in severe renal impairment (CrCl < 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.
Renal excretion accounts for 70-90% of elimination as unchanged drug via glomerular filtration and tubular secretion; biliary/fecal excretion constitutes 10-30%.
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