Valtrex (Valacyclovir)

Generic name: Valacyclovir Hydrochloride Trade names: Valtrex Drug class: Antiviral agent Dosages: 500 mg, 1000 mg tablets Manufacturer: GlaxoSmithKline FDA Approved: December 15, 1995

Description

Valtrex (Valacyclovir hcl), the valine ester of acyclovir, is an antiviral agent active against herpes viruses, varicella-zoster virus, Epstein-Barr virus and to a lesser extent cytomegalovirus. It slows the replication and spread of the virus.

Valtrex is used to treat genital herpes, orofacial herpes (cold sores), and herpes zoster (shingles). It is effective and safe for long-term suppression of recurrent genital herpes. Suppressive therapy is appropriate when outbreaks are frequent, severe, or emotionally disturbing.

Valtrex is proven to reduce the risk of transmission of genital herpes. Valacyclovir suppresses shedding of HSV-2 on genital mucosal surfaces and may prevent sexual transmission of HSV.

Valtrex effectiveness

• provides substantial symptomatic alleviation
• hastens the resolution of itchy, painful, and blistering lesions
• shortens the duration of an outbreak
• reduces the frequency of herpes episodes
• reduces asymptomatic viral shedding
• reduces the risk of transmission of the virus to uninfected partner by 48%
• accelerates the resolution of the herpes zoster rash and associated pain
• decreases the duration of postherpetic neuralgia and incidence of ocular complications (ophthalmic herpes zoster)

In herpes zoster, valacyclovir is more effective than acyclovir and equally effective as famciclovir in shortening the length and severity of shingles-associated pain and postherpetic neuralgia.

Prompt treatment with valacyclovir can abort impending outbreak of both cold sores or genital herpes.

The main limitation of Valtrex - it is not a cure for herpes infections.

Valtrex vs Famvir

Valacyclovir and famciclovir (Famvir) are therapeutically equivalent in the treatment of herpes zoster. Both antivirals have demonstrated the superiority to acyclovir in accelerating the resolution of shingles pain and post-herpetic neuralgia (PHN). Taking into account the difference in price, valacyclovir is a better choice for herpes zoster.

Research suggests that valacyclovir may have a small advantage over famciclovir for suppression of genital herpes and associated viral shedding [1].

Valtrex vs Acyclovir

Main advantages of valacyclovir over acyclovir:

• better oral absorption - valacyclovir has a bioavailability approaching 50% and achieves higher plasma levels of acyclovir
• convenient dosing schedule - valacyclovir is dosed three times a day instead of five times per day as required with acyclovir

First episode genital herpes: Valacyclovir and acyclovir are equally effective in accelerating the resolution of initial episode genital herpes.

Recurrent genital herpes: Both valacyclovir and acyclovir are highly effective in decreasing the length of HSV episode, healing lesions, and suppressing viral shedding.

Suppression of recurrent genital herpes: Both antivirals are similarly effective in suppressing recurrences. Valacyclovir 1 g once daily reduces the yearly recurrence rate by 78% relative to placebo compared with 79% for acyclovir 400 mg twice daily [2].

Shingles: Valacyclovir is more efficacious in alleviating both acute and post herpetic pain, when compared with acyclovir.

So, what to choose: Valtrex or acyclovir? If your primary concern is cost then acyclovir will help you to save money.

However, for suppressive therapy, which will continue for several months, Valtrex would be much more convenient.

• 1. Wald A, Selke S, Warren T, Aoki FY, Sacks S, Diaz-Mitoma F, Corey L. Comparative efficacy of famciclovir and valacyclovir for suppression of recurrent genital herpes and viral shedding. Sex Transm Dis. 2006 Sep;33(9):529-33.
• 2. Reitano M, Tyring S, Lang W, Thoming C, Worm AM, Borelli S, Chambers LO, Robinson JM, Corey L. Valaciclovir for the suppression of recurrent genital herpes simplex virus infection: a large-scale dose range-finding study. International Valaciclovir HSV Study Group. J Infect Dis. 1998 Sep;178(3):603-10.