Clinical Science (43)
Authors: Ormrod Douglas , Goa Karen 
Published: September 2010

Valaciclovir: a review of its use in the management of herpes zoster. (Adis International Limited, Auckland, New Zealand) Drugs 2000;59:1317–1340.

This study compared the effectiveness of valaciclovir (1000 mg 3 times daily for 7 days) and aciclovir (800 mg 5 times daily for 7 days) in controlling the symptoms of acute herpes zoster. Valaciclovir was found to alleviate zoster‐associated pain and postherpetic neuralgia significantly faster than aciclovir. A 14‐day regimen of valaciclovir showed no significant advantage over the 7‐day regimen. A smaller trial in Japanese patients focusing primarily on the cutaneous (rash) signs of herpes zoster confirmed the similar efficacy of valaciclovir and aciclovir in the 7‐day regime. Valaciclovir and aciclovir demonstrated similar efficacy for the control of cutaneous lesions and ocular complications in patients with zoster ophthalmicus. Starting treatment later than 72 h after rash onset did not significantly reduce the beneficial effect of valaciclovir on the duration of zoster‐associated pain, suggesting that valaciclovir might be effective when given later than previously thought. However, valaciclovir should ideally be given as soon as possible after symptoms appear. Valaciclovir was well tolerated with nausea and headache as being the most commonly reported adverse events. The adverse events profile of the agent was similar to that seen with aciclovir or famciclovir. Conclude that the efficacy of valaciclovir for the treatment of herpes zoster has been confirmed and extended by follow‐up studies in herpes zoster ophthalmicus, in Japanese patients, and in the wider primary care setting. Valaciclovir is at least equivalent to, and better in certain parameters than, aciclovir and appears to have similar efficacy to famciclovir 500 mg 3 times daily.

Comment by Susan Anderson, MD.

This is a review article on the antiviral drug valaciclovir. The varicella zoster virus (VZV) is commonly treated with the antiviral drug aciclovir. However, aciclovir has a low oral bioavailability that limits its efficacy in the treatment of herpes zoster. Valaciclovir was developed in order to have a more readily absorbed oral antiviral drug. When valaciclovir was compared to aciclovir in a large study, it was noted that valaciclovir was as effective in controlling the symptoms of acute herpes zoster. It was also noted valaciclovir alleviated zoster associated pain and postherpetic neuralgia significantly faster than aciclovir. Also, there was no significant advantage of treating valaciclovir 14 days versus 7 days; therefore, a 7‐day regimen is recommended. In a smaller trial from Japan that focused primarily on the cutaneous (rash) signs of herpes zoster, there was also confirmation of similar efficacy of aciclovir and valaciclovir in a 7‐day regimen. The similarity in efficacy was not only for cutaneous lesions but also for ocular complications in patients with zoster ophthalmicus. In a large controlled trial, they compared valaciclovir and famciclovir. This showed similar efficacy in resolution of acute herpes zoster rashes shortening the duration of postherpetic neuralgia. It was purposed in the article that the therapeutic window for beneficial treatment with valaciclovir and zoster associated pain may be wider that previously though. It is still recommended that valaciclovir be ideally given as soon as possible after symptoms appear. However, starting treatment after 72 hours after rash onset did not significantly reduce the beneficial effect of the valaciclovir on duration of zoster associated pain. Valaciclovir is known to be well tolerated with nausea and headache being the most commonly reported adverse events. The adverse events profile of valaciclovir is similar to aciclovir or famciclovir. The purpose of this review was to present an overview of the pharmacodynamic/pharmacokinetic properties and therapeutic efficacy in the assessment of pain in herpes zoster in comparison with known agents of aciclovir, famciclovir, and/or placebo.

It is concluded that valaciclovir is an efficacious agent in the treatment of herpes zoster and herpes zoster ophthalmicus. It's at least as efficacious as aciclovir and has similar efficacy to famciclovir. It is well tolerated with a similar side effect profile as aciclovir and famciclovir.