Comparative Pharmacology
Head-to-head clinical analysis: FOSCAVIR versus TYZEKA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOSCAVIR versus TYZEKA.
FOSCAVIR vs TYZEKA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Foscarnet is a pyrophosphate analog that selectively inhibits viral DNA polymerase and reverse transcriptase by binding to the pyrophosphate binding site, preventing the cleavage of pyrophosphate from deoxynucleotide triphosphates, thereby inhibiting viral DNA synthesis. It does not require activation by viral thymidine kinase, making it active against acyclovir-resistant HSV and VZV, and ganciclovir-resistant CMV.
Telbivudine is a synthetic thymidine nucleoside analogue with activity against hepatitis B virus (HBV). It is phosphorylated intracellularly to the active triphosphate form, which competes with natural thymidine triphosphate for incorporation into viral DNA, causing chain termination and inhibition of HBV DNA polymerase (reverse transcriptase).
Induction: 60 mg/kg IV every 8 hours for 2-3 weeks, then maintenance: 90-120 mg/kg IV once daily. Administer as a 2-hour infusion via central line.
600 mg orally once daily
None Documented
None Documented
Terminal elimination half-life is approximately 3-5 hours in patients with normal renal function; can extend to 48-120 hours in severe renal impairment (CrCl <20 mL/min), requiring dose adjustment and therapeutic drug monitoring.
Terminal elimination half-life is approximately 15 hours (range 12-20 hours) in patients with normal renal function; half-life is prolonged in renal impairment, requiring dose adjustment.
Primarily renal excretion (>80% as unchanged drug) via glomerular filtration and tubular secretion; minimal biliary/fecal elimination (<5%).
Renal excretion of unchanged drug accounts for approximately 40% of the administered dose; biliary/fecal excretion accounts for approximately 60%.
Category C
Category C
Antiviral
Antiviral, Hepatitis B