Comparative Pharmacology
Head-to-head clinical analysis: MYTREX A versus SULFATRIM SS.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MYTREX A versus SULFATRIM SS.
MYTREX A vs SULFATRIM-SS
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Methotrexate inhibits dihydrofolate reductase, leading to depletion of tetrahydrofolate and inhibition of DNA synthesis and cell proliferation. Also has immunomodulatory effects via adenosine release.
Sulfamethoxazole inhibits bacterial dihydropteroate synthase, blocking folate synthesis. Trimethoprim inhibits bacterial dihydrofolate reductase, blocking reduction of dihydrofolate to tetrahydrofolate. Sequential blockade produces bactericidal synergy.
Methotrexate (MYTREX A) 7.5-25 mg orally once weekly, or 15-25 mg intramuscularly/subcutaneously once weekly for rheumatoid arthritis; in oncology, dosing varies per protocol.
1 double-strength tablet (160 mg trimethoprim / 800 mg sulfamethoxazole) orally every 12 hours for 10-14 days.
None Documented
None Documented
Terminal elimination half-life: 12-15 hours in normal renal function; prolonged to 24-30 hours in moderate to severe renal impairment (CrCl <30 mL/min).
SMX: 9-12 hours (increased in renal impairment); TMP: 8-11 hours (increased in renal impairment); both prolonged in elderly.
Renal: 90% unchanged drug; fecal: <10% via bile; minor hepatic metabolism to inactive metabolites.
Renal excretion of unchanged sulfamethoxazole (SMX) approximately 20%, trimethoprim (TMP) approximately 60%; biliary/fecal elimination minor (SMX <5%, TMP <10%).
Category C
Category C
Sulfonamide Antibiotic
Sulfonamide Antibiotic