Comparative Pharmacology
Head-to-head clinical analysis: COTRIM D S versus RIFAXIMIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COTRIM D S versus RIFAXIMIN.
COTRIM D.S. vs RIFAXIMIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
COTRIM D.S. is a combination of sulfamethoxazole, a competitive inhibitor of dihydropteroate synthase, and trimethoprim, a reversible inhibitor of dihydrofolate reductase. This sequential blockade of folate synthesis leads to bactericidal activity.
Rifaximin is a non-aminoglycoside, semi-synthetic antibiotic derived from rifamycin that inhibits bacterial RNA synthesis by binding to the beta-subunit of bacterial DNA-dependent RNA polymerase, thereby blocking transcription.
160 mg trimethoprim / 800 mg sulfamethoxazole (one double-strength tablet) orally every 12 hours.
550 mg orally three times daily for 14 days for travelers' diarrhea; 200 mg orally three times daily for 3 days for irritable bowel syndrome with diarrhea; 400 mg orally three times daily for 7 days for hepatic encephalopathy.
None Documented
None Documented
Clinical Note
moderateRifaximin + Digoxin
"The serum concentration of Digoxin can be increased when it is combined with Rifaximin."
Clinical Note
moderateRifaximin + Levofloxacin
"The serum concentration of Levofloxacin can be increased when it is combined with Rifaximin."
Clinical Note
moderateRifaximin + Estrone sulfate
"The serum concentration of Estrone sulfate can be decreased when it is combined with Rifaximin."
Clinical Note
moderateRifaximin + Tranilast
Sulfamethoxazole: 9-12 hours (normal renal function). Trimethoprim: 8-11 hours. Both are prolonged in renal impairment (e.g., creatinine clearance <30 mL/min: >24 hours). Clinical context: dosing interval is typically 12 hours; dose adjustment required if CrCl <30 mL/min.
The terminal elimination half-life is approximately 1.8 to 2.5 hours in patients with normal hepatic function. Due to negligible systemic absorption, the half-life has limited clinical relevance; drug action is largely confined to the gastrointestinal tract.
Sulfamethoxazole: ~20% unchanged in urine, remainder as acetylated and glucuronide metabolites. Trimethoprim: ~50-80% unchanged in urine, remainder as oxidative metabolites. Both undergo renal excretion via glomerular filtration and tubular secretion. Total renal elimination: 70-90% of dose combined. Biliary/fecal: <10%.
Rifaximin is primarily eliminated in feces as unchanged drug (>96% of an oral dose). Renal excretion is negligible (<0.4%). Biliary excretion is minimal due to poor systemic absorption.
Category C
Category A/B
Antibiotic
Antibiotic
"The serum concentration of Tranilast can be decreased when it is combined with Rifaximin."