Comparative Pharmacology
Head-to-head clinical analysis: ABACAVIR LAMIVUDINE versus ABACAVIR SULFATE LAMIVUDINE AND ZIDOVUDINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ABACAVIR LAMIVUDINE versus ABACAVIR SULFATE LAMIVUDINE AND ZIDOVUDINE.
ABACAVIR; LAMIVUDINE vs ABACAVIR SULFATE, LAMIVUDINE AND ZIDOVUDINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Abacavir is a carbocyclic synthetic nucleoside analogue (guanosine analogue) that is phosphorylated intracellularly to carbovir triphosphate, which competes with deoxyguanosine triphosphate for incorporation into viral DNA by HIV reverse transcriptase, leading to chain termination. Lamivudine is a synthetic nucleoside analogue (cytosine analogue) that is phosphorylated intracellularly to lamivudine triphosphate, which competes with deoxycytidine triphosphate for incorporation into viral DNA by HIV reverse transcriptase, causing chain termination.
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).
One tablet (abacavir 600 mg/lamivudine 300 mg) orally once daily with or without food. Can be used in combination with other antiretrovirals.
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.
None Documented
None Documented
Abacavir: 1.5 hr (single dose) to 2 hr (steady state), clinically short requiring twice-daily dosing. Lamivudine: 5-7 hr (adults), extended in renal impairment (up to 20 hr with CrCl <50 mL/min).
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.
Abacavir: 83% renal (1.2% unchanged, rest as metabolites), 16% fecal. Lamivudine: ~70% renal (mostly unchanged via tubular secretion), ~5% fecal.
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).
Category A/B
Category A/B
NRTI
NRTI