Comparative Pharmacology
Head-to-head clinical analysis: ABITREXATE versus XELODA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ABITREXATE versus XELODA.
ABITREXATE vs XELODA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Methotrexate, the active ingredient, is a folate analog that inhibits dihydrofolate reductase (DHFR), thereby blocking the conversion of dihydrofolate to tetrahydrofolate, inhibiting DNA synthesis, repair, and cellular replication. It also has immunosuppressive and anti-inflammatory effects via modulation of adenosine and cytokine pathways.
Prodrug of 5-fluorouracil (5-FU), inhibits thymidylate synthase, incorporates into RNA and DNA, leading to cell death.
7.5 mg orally once weekly; alternatively, 7.5 mg subcutaneously once weekly. Dose may be increased by 2.5 mg every 1-2 weeks up to 20 mg once weekly based on response and tolerability.
Capecitabine 1250 mg/m2 orally twice daily for 2 weeks followed by a 1-week rest period, administered as 3-week cycles.
None Documented
None Documented
Terminal elimination half-life is 6-12 hours (mean 7.5 hours) in patients with normal renal function; prolonged in renal impairment.
Capecitabine: 0.65-0.85 h; 5'-DFCR: 0.9-1.1 h; 5'-DFUR: 0.75-1.0 h; 5-FU: 0.75-1.1 h. Terminal half-life of 5-FU is short, requiring continuous dosing for sustained exposure.
Primarily renal (80-90% as unchanged drug) via glomerular filtration and active tubular secretion; biliary/fecal excretion accounts for <10%.
Renal (95.5% as metabolites; 26.1% as parent drug and metabolites, primarily 5'-DFCR, 5'-DFUR, and FBAL); fecal (< 3%)
Category C
Category C
Antimetabolite
Antimetabolite