Comparative Pharmacology
Head-to-head clinical analysis: EPZICOM versus STAVZOR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EPZICOM versus STAVZOR.
EPZICOM vs STAVZOR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
EPZICOM is a combination of abacavir and lamivudine, both nucleoside reverse transcriptase inhibitors (NRTIs). Abacavir is a guanosine analogue that is phosphorylated to carbovir triphosphate, which competes with dGTP for incorporation into viral DNA and causes chain termination. Lamivudine is a cytidine analogue that is phosphorylated to lamivudine triphosphate, which inhibits HIV-1 reverse transcriptase via DNA chain termination.
Stavudine is a nucleoside analogue reverse transcriptase inhibitor (NRTI). It is phosphorylated intracellularly to stavudine triphosphate, which competes with natural substrate deoxythymidine triphosphate and inhibits HIV-1 reverse transcriptase by incorporating into viral DNA, causing chain termination.
One tablet (600 mg abacavir/300 mg lamivudine) orally once daily.
300 mg orally twice daily.
None Documented
None Documented
Abacavir: 1.54 ± 0.63 hours (terminal), Lamivudine: 13-19 hours (terminal); effective half-life of abacavir 1.5 hours, lamivudine 12-15 hours at steady state.
Terminal elimination half-life is approximately 1.0-1.6 hours in adults with normal renal function. In patients with renal impairment, half-life is prolonged (up to 8-14 hours with creatinine clearance <10 mL/min), requiring dose adjustment. Intracellular (active triphosphate) half-life is 3.5-7 hours.
Abacavir: 83% as metabolites in urine, 16% in feces; Lamivudine: 71% unchanged in urine within 24 hours, 5-10% as trans-sulfoxide metabolite in urine; Biliary excretion minimal.
Stavudine is eliminated primarily by renal excretion (approximately 40% of an administered dose is recovered unchanged in urine within 6 hours, with up to 60-70% overall) and to a lesser extent by fecal excretion (approximately 30%). Active tubular secretion contributes to renal elimination.
Category C
Category C
NRTI Antiretroviral
NRTI Antiretroviral