Comparative Pharmacology
Head-to-head clinical analysis: ERYTHROMYCIN ETHYLSUCCINATE AND SULFISOXAZOLE ACETYL versus R P MYCIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ERYTHROMYCIN ETHYLSUCCINATE AND SULFISOXAZOLE ACETYL versus R P MYCIN.
ERYTHROMYCIN ETHYLSUCCINATE AND SULFISOXAZOLE ACETYL vs R-P MYCIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Erythromycin ethylsuccinate is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, blocking peptide chain elongation. Sulfisoxazole acetyl is a sulfonamide that inhibits dihydropteroate synthase, blocking folic acid synthesis.
R-P MYCIN is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S subunit of the bacterial ribosome, specifically at the 23S rRNA of the peptidyl transferase center. This action blocks the translocation step, thereby preventing the elongation of the peptide chain.
Erythromycin ethylsuccinate (400 mg) and sulfisoxazole acetyl (600 mg) per 5 mL suspension: 2-3 teaspoonfuls (10-15 mL) orally every 6 hours for 10-14 days. Maximum daily dose: 6 g sulfisoxazole.
Rifampin 600 mg orally once daily or 10 mg/kg intravenously once daily.
None Documented
None Documented
Erythromycin: terminal half-life of 1.4-2.0 hours in adults; prolonged to 4-6 hours in anuria. Sulfisoxazole: half-life 4.5-7 hours in adults; increased in renal impairment. The combination's clinical context warrants dosing interval adjustments in renal dysfunction.
Terminal half-life 2-3 hours; prolonged in renal impairment (up to 6-8 hours in anuria).
Erythromycin ethylsuccinate is primarily excreted in bile (up to 80% as unchanged drug), with about 12-15% eliminated renally. Sulfisoxazole acetyl is renally excreted, with approximately 85% of the dose appearing in urine as acetylated and deacetylated metabolites. Fecal elimination accounts for less than 10% of sulfisoxazole.
Renal (60-80% unchanged), biliary/fecal (15-20%).
Category A/B
Category C
Macrolide Antibiotic
Macrolide Antibiotic