Comparative Pharmacology
Head-to-head clinical analysis: NITROFURANTOIN MONOHYDRATE MACROCRYSTALS versus SEPTRA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NITROFURANTOIN MONOHYDRATE MACROCRYSTALS versus SEPTRA.
NITROFURANTOIN (MONOHYDRATE/MACROCRYSTALS) vs SEPTRA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates that inhibit bacterial cell wall synthesis, protein synthesis, and DNA/RNA synthesis. It is bacteriostatic at low concentrations and bactericidal at higher concentrations.
SEPTRA (trimethoprim/sulfamethoxazole) is a combination of two antifolate agents: sulfamethoxazole inhibits dihydropteroate synthase, blocking the conversion of PABA to dihydrofolic acid; trimethoprim inhibits dihydrofolate reductase, preventing the reduction of dihydrofolic acid to tetrahydrofolic acid. This sequential blockade disrupts bacterial folate synthesis and nucleic acid production.
100 mg orally twice daily for 5-7 days; for uncomplicated urinary tract infection.
Trimethoprim-sulfamethoxazole (TMP-SMX) 160 mg/800 mg (double strength) orally every 12 hours; for severe infections, intravenous dosing: 8-10 mg/kg/day (TMP component) divided every 6, 8, or 12 hours.
None Documented
None Documented
Terminal elimination half-life: 20-60 minutes (average ~30 min) in patients with normal renal function; prolonged in renal impairment (e.g., CrCl <60 mL/min).
Sulfamethoxazole: 9-12 hours (normal renal function); Trimethoprim: 8-11 hours (normal renal function). In severe renal impairment (CrCl <15 mL/min), half-life prolongs significantly (up to 24-30 hours for sulfamethoxazole, 20-30 hours for trimethoprim).
Renal excretion of unchanged drug accounts for approximately 40% of the dose; tubular reabsorption occurs. Biliary/fecal elimination is minimal (<5%).
Renal excretion of unchanged sulfamethoxazole (~20%) and trimethoprim (~50-60%) with additional hepatic metabolism (acetylation, glucuronidation) of sulfamethoxazole; total renal elimination accounts for ~80-90% of the dose (sulfamethoxazole 30% parent, 40% metabolites; trimethoprim 60-80% parent, remainder as metabolites). Biliary/fecal <5%.
Category D/X
Category C
Antibiotic
Antibiotic