Comparative Pharmacology
Head-to-head clinical analysis: FOSCAVIR versus HERPLEX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOSCAVIR versus HERPLEX.
FOSCAVIR vs HERPLEX
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.
Inhibits viral DNA polymerase after phosphorylation to acyclovir triphosphate, leading to chain termination and inhibition of herpes simplex virus replication.
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.
Acyclovir 200 mg orally 5 times daily for 10 days for initial genital herpes; 400 mg orally twice daily for suppressive therapy; 5-10 mg/kg IV every 8 hours for severe infections.
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.
2.5–3.3 hours in adults with normal renal function; prolonged to 10–20 hours in anuria (CrCl <10 mL/min); requires dose adjustment in renal impairment
Primarily renal excretion (>80% as unchanged drug) via glomerular filtration and tubular secretion; minimal biliary/fecal elimination (<5%).
Renal: ~90% as unchanged drug via glomerular filtration and tubular secretion; minor biliary/fecal elimination (<2%)
Category C
Category C
Antiviral
Antiviral