Comparative Pharmacology
Head-to-head clinical analysis: EPIVIR versus EPZICOM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EPIVIR versus EPZICOM.
EPIVIR vs EPZICOM
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI). It is phosphorylated intracellularly to lamivudine triphosphate, which competes with endogenous deoxycytidine triphosphate for incorporation into viral DNA by HIV reverse transcriptase and hepatitis B virus polymerase, resulting in DNA chain termination.
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.
300 mg orally once daily or 150 mg orally twice daily
One tablet (600 mg abacavir/300 mg lamivudine) orally once daily.
None Documented
None Documented
Terminal elimination half-life is 5 to 7 hours in adults with normal renal function. In neonates, half-life is prolonged (up to 12-18 hours). Clinically, dosing interval adjustments are required for creatinine clearance <30 mL/min.
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.
Renal excretion of unchanged drug accounts for approximately 70% of elimination, with active tubular secretion contributing significantly. Biliary/fecal elimination is minimal (<10%).
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.
Category C
Category C
NRTI Antiretroviral
NRTI Antiretroviral