Comparative Pharmacology
Head-to-head clinical analysis: ACYCLOVIR versus FAMVIR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ACYCLOVIR versus FAMVIR.
ACYCLOVIR vs FAMVIR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Acyclovir is a synthetic nucleoside analog that inhibits viral DNA replication. It is phosphorylated to acyclovir monophosphate by viral thymidine kinase, then converted to acyclovir triphosphate by cellular kinases. Acyclovir triphosphate competes with deoxyguanosine triphosphate for viral DNA polymerase, incorporating into viral DNA and causing chain termination.
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.
400 mg orally twice daily for herpes zoster; 200 mg orally 5 times daily for genital herpes; 5-10 mg/kg intravenously every 8 hours for severe infections.
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
Clinical Note
moderateAcyclovir + Teriflunomide
"The serum concentration of Teriflunomide can be increased when it is combined with Acyclovir."
Clinical Note
moderateTizanidine + Acyclovir
"The serum concentration of Acyclovir can be increased when it is combined with Tizanidine."
None Documented
Terminal elimination half-life is 2.5–3.3 hours in adults with normal renal function; increases to 19.5 hours in anuria.
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 62-90% of elimination. Fecal elimination is <2%.
Renal: 60–70% as penciclovir via tubular secretion and glomerular filtration; fecal: <10%; biliary: <1%.
Category A/B
Category C
Antiviral
Antiviral