Comparative Pharmacology
Head-to-head clinical analysis: TRIMETH SULFA versus TRIPLE SULFAS.
Peer-Reviewed Evidence
Head-to-head clinical analysis: TRIMETH SULFA versus TRIPLE SULFAS.
TRIMETH/SULFA vs TRIPLE SULFAS
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Competitive inhibition of dihydropteroate synthase, thereby blocking folate synthesis and bacterial DNA replication. Triple sulfas (sulfadiazine, sulfamerazine, sulfamethazine) act synergistically to inhibit folic acid synthesis.
1 double-strength tablet (160 mg trimethoprim / 800 mg sulfamethoxazole) orally every 12 hours for 14 days.
1 to 2 tablets (each containing sulfadiazine 167 mg, sulfamerazine 167 mg, sulfamethazine 167 mg) orally every 4 hours initially, then 2 tablets every 6 hours. Maximum daily dose: 6 grams of total sulfonamide.
None Documented
None Documented
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.
Terminal elimination half-life ranges from 10-12 hours in adults with normal renal function. Prolonged in renal impairment (up to 24-48 hours) and neonates (40-120 hours).
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.
Primarily renal; approximately 70-100% excreted unchanged in urine via glomerular filtration and tubular secretion. Minor biliary/fecal elimination (<5%) with enterohepatic circulation possible.
Category C
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic