Comparative Pharmacology
Head-to-head clinical analysis: SULFISOXAZOLE versus TRIMETHOPRIM SULFAMETHOXAZOLE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SULFISOXAZOLE versus TRIMETHOPRIM SULFAMETHOXAZOLE.
SULFISOXAZOLE vs Trimethoprim-Sulfamethoxazole
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sulfisoxazole is a sulfonamide antibiotic that inhibits bacterial dihydropteroate synthase, blocking the synthesis of dihydrofolic acid and ultimately inhibiting bacterial folate synthesis and DNA replication.
Sulfamethoxazole inhibits dihydropteroate synthase, blocking para-aminobenzoic acid incorporation into dihydrofolate; trimethoprim inhibits dihydrofolate reductase, preventing tetrahydrofolate formation. Sequential blockade of folate synthesis.
1-2 g orally once, then 500 mg-1 g orally every 4-6 hours; maximum 6 g/day.
Oral: 160 mg TMP/800 mg SMX every 12 hours; IV: 8-10 mg/kg/day (based on TMP) in 2-4 divided doses
None Documented
None Documented
Clinical Note
moderateSulfisoxazole + Gatifloxacin
"Sulfisoxazole may increase the hypoglycemic activities of Gatifloxacin."
Clinical Note
moderateSulfisoxazole + Rosoxacin
"Sulfisoxazole may increase the hypoglycemic activities of Rosoxacin."
Clinical Note
moderateSulfisoxazole + Trovafloxacin
"Sulfisoxazole may increase the hypoglycemic activities of Trovafloxacin."
Clinical Note
moderateSulfisoxazole + Nalidixic acid
Terminal elimination half-life is 5-7 hours in adults with normal renal function; prolonged to 12-20 hours in renal impairment (CrCl <30 mL/min).
Trimethoprim: 8-10 hours (normal renal function); prolonged to 24-30 hours in severe renal impairment (CrCl <10 mL/min). Sulfamethoxazole: 9-11 hours; prolonged in renal failure. The combination retains a half-life of ~10-12 hours in healthy adults, requiring dose adjustment in renal impairment.
Renal excretion accounts for 70-85% of elimination, predominantly as unchanged drug (30-50%) and the N4-acetyl metabolite (15-30%). Biliary/fecal excretion is minimal (<5%).
Trimethoprim: 50-60% excreted unchanged in urine via glomerular filtration and tubular secretion; 10-20% as metabolites. Sulfamethoxazole: 20-30% excreted unchanged in urine; 50-70% as N4-acetylated metabolite. Both undergo minimal biliary/fecal elimination (<5% total).
Category C
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic
"Sulfisoxazole may increase the hypoglycemic activities of Nalidixic acid."