Comparative Pharmacology
Head-to-head clinical analysis: CIDOFOVIR versus FAMVIR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CIDOFOVIR versus FAMVIR.
CIDOFOVIR vs FAMVIR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Cidofovir is a nucleotide analog that inhibits viral DNA polymerase by competing with deoxycytidine triphosphate for incorporation into viral DNA, resulting in chain termination and inhibition of viral replication.
Famciclovir is a prodrug that is rapidly converted to penciclovir, which inhibits viral DNA polymerase by competing with deoxyguanosine triphosphate, thereby inhibiting viral DNA synthesis and replication.
5 mg/kg intravenously once weekly for 2 weeks, then 5 mg/kg every 2 weeks. Administer with probenecid 2 g orally 3 hours before dose, then 1 g at 2 and 8 hours after dose. Hydrate with 1 L normal saline before infusion.
250 mg orally three times daily for 7 days for herpes zoster; 125 mg orally twice daily for 5 days for recurrent genital herpes; 250 mg orally twice daily for 7 days for first-episode genital herpes; 500 mg orally twice daily for 7 days for herpes zoster in immunocompromised patients; 500 mg orally twice daily for 7 days for recurrent mucocutaneous herpes in HIV patients.
None Documented
None Documented
Clinical Note
moderateCidofovir + Teriflunomide
"The serum concentration of Teriflunomide can be increased when it is combined with Cidofovir."
Clinical Note
moderateTenofovir disoproxil + Cidofovir
"Tenofovir disoproxil may decrease the excretion rate of Cidofovir which could result in a higher serum level."
Terminal elimination half-life is approximately 2.5 hours. However, the intracellular half-life of the active diphosphate metabolite is >48 hours, supporting once-weekly dosing.
Terminal elimination half-life of penciclovir is approximately 2–3 hours in patients with normal renal function; extends to 9–18 hours in severe renal impairment (CrCl <30 mL/min).
Renal excretion of unchanged drug via glomerular filtration and tubular secretion accounts for approximately 90% of the administered dose. Biliary/fecal elimination is minimal (<5%).
Renal: 60–70% as penciclovir via tubular secretion and glomerular filtration; fecal: <10%; biliary: <1%.
Category D/X
Category C
Antiviral
Antiviral