Comparative Pharmacology
Head-to-head clinical analysis: FOSCAVIR versus PENCICLOVIR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOSCAVIR versus PENCICLOVIR.
FOSCAVIR vs PENCICLOVIR
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.
Penciclovir is a nucleoside analog that inhibits viral DNA polymerase. It is phosphorylated by viral thymidine kinase to penciclovir triphosphate, which competitively inhibits viral DNA polymerase and terminates DNA chain elongation.
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.
Topical: Apply 1% cream every 2 hours while awake (approximately 9 times/day) for 4 days. Oral: 500 mg twice daily for 5 days.
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 half-life: 2.0–2.5 hours (healthy adults); prolonged to ~9–10 hours in renal impairment (CrCl <30 mL/min); clinical context: dosing interval adjusted based on renal function.
Primarily renal excretion (>80% as unchanged drug) via glomerular filtration and tubular secretion; minimal biliary/fecal elimination (<5%).
Renal excretion: >70% as unchanged penciclovir via glomerular filtration and tubular secretion.
Category C
Category A/B
Antiviral
Antiviral