Comparative Pharmacology
Head-to-head clinical analysis: EFAVIRENZ EMTRICITABINE AND TENOFOVIR ALAFENAMIDE versus EMTRICITABINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EFAVIRENZ EMTRICITABINE AND TENOFOVIR ALAFENAMIDE versus EMTRICITABINE.
EFAVIRENZ, EMTRICITABINE AND TENOFOVIR ALAFENAMIDE vs EMTRICITABINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that binds directly and reversibly to the reverse transcriptase enzyme, causing a conformation change and inhibiting RNA-dependent and DNA-dependent DNA polymerase activity. Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) that is phosphorylated to its active triphosphate form, which competes with deoxycytidine triphosphate and incorporates into viral DNA, causing chain termination. Tenofovir alafenamide is a prodrug of tenofovir, an NRTI; it is taken up by hepatocytes and activated to tenofovir diphosphate, which inhibits reverse transcriptase by competing with deoxyadenosine triphosphate and causing DNA chain termination.
Nucleoside reverse transcriptase inhibitor; phosphorylated to emtricitabine triphosphate which competes with endogenous deoxycytidine triphosphate and incorporates into viral DNA causing chain termination.
One tablet (600 mg efavirenz/200 mg emtricitabine/25 mg tenofovir alafenamide) orally once daily on an empty stomach, preferably at bedtime.
200 mg orally once daily, typically in combination with other antiretroviral agents.
None Documented
None Documented
Efavirenz: 52-76 h (single dose), 40-55 h (multiple doses). Emtricitabine: ~10 h. Tenofovir alafenamide: 0.51 h (parent drug), 32.4 h (tenofovir, terminal half-life).
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).
Efavirenz: 14-34% renal (as unchanged drug <1%), 16-61% fecal (as parent drug/metabolites). Emtricitabine: ~86% renal (as unchanged drug). Tenofovir alafenamide: <1% renal (as unchanged drug), ~31.5% fecal (as parent drug), remainder as tenofovir (metabolite) which undergoes renal filtration and active tubular secretion.
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