Comparative Pharmacology
Head-to-head clinical analysis: SEPTRA DS versus TRIMETHOPRIM SULFATE AND POLYMYXIN B SULFATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SEPTRA DS versus TRIMETHOPRIM SULFATE AND POLYMYXIN B SULFATE.
SEPTRA DS vs TRIMETHOPRIM SULFATE AND POLYMYXIN B SULFATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
SEPTRA DS is a combination of trimethoprim and sulfamethoxazole. Trimethoprim inhibits bacterial dihydrofolate reductase, while sulfamethoxazole inhibits dihydropteroate synthase, sequentially blocking folate synthesis and ultimately DNA synthesis in susceptible bacteria.
Trimethoprim inhibits bacterial dihydrofolate reductase, blocking tetrahydrofolate synthesis and thereby inhibiting thymidine synthesis. Polymyxin B disrupts bacterial cell membrane integrity by binding to lipopolysaccharides in Gram-negative bacteria.
One DS tablet (800 mg sulfamethoxazole/160 mg trimethoprim) orally every 12 hours for 10-14 days.
One drop in each affected eye every 2 to 4 hours for 7 to 10 days.
None Documented
None Documented
Trimethoprim: 8-10 hours; sulfamethoxazole: 10-12 hours (prolonged in renal impairment, e.g., creatinine clearance <30 mL/min increases half-life to >20 hours).
Trimethoprim: 8-10 hours (normal renal function); Polymyxin B: 6 hours (prolonged in renal impairment).
Renal excretion of unchanged drugs accounts for 50-70% of trimethoprim and 20-30% of sulfamethoxazole; biliary excretion is minor (<10% total).
Trimethoprim: renal (80-90% unchanged, 10-20% metabolites); Polymyxin B: renal (60% unchanged, 40% nonrenal).
Category C
Category D/X
Antibiotic
Antibiotic