Comparative Pharmacology
Head-to-head clinical analysis: ILOSONE SULFA versus TRIMETHOPRIM SULFAMETHOXAZOLE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ILOSONE SULFA versus TRIMETHOPRIM SULFAMETHOXAZOLE.
ILOSONE SULFA vs Trimethoprim-Sulfamethoxazole
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Ilosone (erythromycin) is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. Sulfa (sulfisoxazole) is a sulfonamide that inhibits dihydropteroate synthase, blocking folate synthesis. The combination provides synergistic bacteriostatic activity.
Sulfamethoxazole inhibits dihydropteroate synthase, blocking para-aminobenzoic acid incorporation into dihydrofolate; trimethoprim inhibits dihydrofolate reductase, preventing tetrahydrofolate formation. Sequential blockade of folate synthesis.
Each 5 mL suspension contains 250 mg erythromycin base and 600 mg sulfisoxazole; typical adult dose is 10 mL (2 tsp) every 6 hours, not to exceed 40 mL/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
Erythromycin: 1.5-2 hours; Sulfisoxazole: 4-7 hours; clinical context: dose adjustment in renal impairment (CrCl <50 mL/min) needed for sulfisoxazole
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: 70-80% as unchanged drug and active metabolite (sulfisoxazole); Biliary: 10-15% as metabolites; Fecal: <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
Macrolide and Sulfonamide Antibiotic
Sulfonamide Antibiotic