Comparative Pharmacology
Head-to-head clinical analysis: ABACAVIR SULFATE LAMIVUDINE AND ZIDOVUDINE versus EMTRICITABINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ABACAVIR SULFATE LAMIVUDINE AND ZIDOVUDINE versus EMTRICITABINE.
ABACAVIR SULFATE, LAMIVUDINE AND ZIDOVUDINE vs EMTRICITABINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Abacavir is a carbocyclic synthetic nucleoside analog guanosine analogue that is phosphorylated to carbovir triphosphate, which inhibits HIV-1 reverse transcriptase by competing with natural substrate dGTP and causing chain termination. Lamivudine is a dideoxy-nucleoside cytidine analogue that is phosphorylated to lamivudine triphosphate, which inhibits HIV-1 reverse transcriptase via incorporation into viral DNA and chain termination. Zidovudine is a thymidine analogue that is phosphorylated to zidovudine triphosphate, which inhibits HIV-1 reverse transcriptase by competing with dTTP and causing chain termination. All three drugs are nucleoside reverse transcriptase inhibitors (NRTIs).
Nucleoside reverse transcriptase inhibitor; phosphorylated to emtricitabine triphosphate which competes with endogenous deoxycytidine triphosphate and incorporates into viral DNA causing chain termination.
One tablet (abacavir 600 mg/lamivudine 300 mg/zidovudine 300 mg) twice daily or as a single tablet once daily (abacavir 600 mg/lamivudine 300 mg/zidovudine 300 mg) depending on formulation.
200 mg orally once daily, typically in combination with other antiretroviral agents.
None Documented
None Documented
Abacavir: 1.5 h; lamivudine: 5-7 h; zidovudine: 0.5-3 h. Terminal half-lives: abacavir ~1.5 h, lamivudine ~13-19 h intracellularly (active triphosphate), zidovudine ~1 h (plasma) but intracellular triphosphate ~3-4 h. Clinical context: Twice-daily dosing due to prolonged intracellular half-life of active metabolites.
Terminal elimination half-life is approximately 10 hours (range 8–12 hours) in adults with normal renal function; prolonged to >20 hours in severe renal impairment (CrCl <30 mL/min).
Renal excretion of unchanged drug and metabolites: abacavir (83% as metabolites, 1% unchanged), lamivudine (70% unchanged), zidovudine (72-74% as metabolites, 14-18% unchanged). Biliary/fecal elimination is minor (<10% for each component).
Renal: approximately 86% of the dose is excreted unchanged in urine via glomerular filtration and active tubular secretion. Biliary/fecal: minimal (<14% as unchanged drug and metabolites in feces).
Category A/B
Category C
NRTI
Antiretroviral, NRTI