Valaciclovir

Abstract

Valaciclovir, the L-valyl ester of aciclovir (acyclovir), is an oral prodrug that undergoes rapid and extensive first-pass metabolism to yield aciclovir and the essential amino acid L-valine. Aciclovir, the active antiviral component of valaciclovir, shows good in vitro activity against the herpesviruses herpes simplex virus (HSV)-1, HSV-2 and varicella zoster virus. The bioavailability of aciclovir from oral valaciclovir is considerably greater than that achieved after oral aciclovir administration. Thus, valaciclovir delivers therapeutic aciclovir concentrations when administered in a less frequent oral dosage regimen than is required for aciclovir. Valaciclovir is an effective treatment for herpes zoster in immunocompetent adults. In a large comparative study that included patients > or = 50 years of age, valaciclovir (1000mg 3 times daily for 7 or 14 days) and oral aciclovir (800mg 5 times daily) were equally effective in achieving resolution of cutaneous zoster lesions. Importantly, valaciclovir was significantly more effective than aciclovir in reducing the duration of zoster-associated pain. Preliminary results of several studies indicate that valaciclovir (500 to 1000mg twice daily for 5 to 10 days) is as effective as aciclovir (200mg 5 times a day for 5 to 10 days) in the treatment of genital herpes. In patients with first or recurrent episodes of genital herpes, valaciclovir reduced the duration of viral shedding, hastened lesion healing and decreased lesion-associated pain. Valaciclovir was also effective in suppressing recurrent episodes of genital herpes and significantly prolonged the time to a recurrent episode of infection compared with placebo. Valaciclovir is a well tolerated drug; in herpes zoster and HSV studies its tolerability profile was similar to that of aciclovir or placebo. Valaciclovir represents and advance in antiherpes drug therapy and is a useful treatment option for patients with herpes zoster or genital herpes. It is at least as effective as aciclovir and is administered in a more convenient oral dosage regimen. Thus, valaciclovir may ultimately succeed aciclovir as a first-line treatment for genital herpes or herpes zoster.

Stability evaluation and sensitive determination of antiviral drug, valacyclovir and its metabolite acyclovir in human plasma by a rapid liquid chromatography–tandem mass spectrometry method

“…It has plasma protein binding in the range of 9-33%, which is independent of plasma ACV concentration. After single 100-1000 mg doses of VCV, the area under the plasma concentration-time curve for ACV ranged from 2.28-19.5 h mg/L and the mean plasma elimination half-life of 2.62-3.13 h [6].…”

Identification of a Human Valacyclovirase

“…Recently, amino acid ester prodrugs of nucleoside analogs such as valacyclovir (VACV) and valganciclovir (VGCV) have been shown to significantly increase their oral absorption (5)(6)(7)(8). The valyl ester prodrug of acyclovir (ACV), valacyclovir, increases the oral bioavailability of ACV 3-to 5-fold (9).…”

Meta-Herpetic Keratitis and Therapeutic Approach: Case Report

“…LE was shown to be highly lipophilic, and the highest concentrations of LE were reported to be found in the cornea followed by the iris, ciliary body and the aqueous humor [7]. Previous studies related to comparison of oral anti-viral therapy with valacyclovir or acyclovir revealed similar anti-viral potencies with less frequent dosages of valacyclovir [8] [9]. Valacyclovir 500 -1000 mg twice a day is found as effective as acyclovir 200 mg five times a Day [9].…”

“…Previous studies related to comparison of oral anti-viral therapy with valacyclovir or acyclovir revealed similar anti-viral potencies with less frequent dosages of valacyclovir [8] [9]. Valacyclovir 500 -1000 mg twice a day is found as effective as acyclovir 200 mg five times a Day [9]. Valacyclovir has been recommended for the patients having difficulty in complying with the acyclovir doses [10].…”