Comparative Pharmacology
Head-to-head clinical analysis: VALACYCLOVIR HYDROCHLORIDE versus ZOVIRAX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: VALACYCLOVIR HYDROCHLORIDE versus ZOVIRAX.
VALACYCLOVIR HYDROCHLORIDE vs ZOVIRAX
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Valacyclovir hydrochloride is a prodrug of acyclovir. After oral administration, it is rapidly converted to acyclovir, which inhibits viral DNA polymerase, leading to chain termination and inhibition of viral DNA replication.
After intracellular phosphorylation to acyclovir triphosphate, selectively inhibits viral DNA polymerase and incorporates into viral DNA, causing chain termination.
500 mg orally twice daily for recurrent genital herpes; 1 g orally twice daily for herpes zoster; 1 g orally three times daily for herpes simplex encephalitis or immunocompromised patients.
Herpes simplex: 200 mg orally 5 times daily for 10 days; or 400 mg orally 3 times daily for 5-10 days. Herpes zoster: 800 mg orally 5 times daily for 7-10 days. IV: 5-10 mg/kg every 8 hours for immunocompromised patients with HSV/VZV.
None Documented
None Documented
Terminal elimination half-life: 2.5–3.3 hours in patients with normal renal function; prolonged to 14 hours in renal impairment (CrCl 15–30 mL/min).
Terminal elimination half-life is 2.5-3.3 hours in adults with normal renal function; prolonged to 19.5 hours in anuria (creatinine clearance <10 mL/min).
Renal excretion: >90% as unchanged drug and inactive metabolite (9-carboxymethoxymethylguanine). Biliary/fecal: <2%.
Renal excretion of unchanged drug via glomerular filtration and tubular secretion accounts for 76-82% of elimination; fecal excretion is less than 2%.
Category A/B
Category C
Antiviral
Antiviral