Valacyclovir: approved and off-label uses for the treatment of herpes virus infections in immunocompetent and immunocompromised adults.

IMPORTANCE OF THE FIELD: Herpes viruses are associated with a wide spectrum of clinical diseases and impose considerable morbidity and even mortality in immunosuppressed hosts. Although there is no cure for these conditions, available treatments alleviate symptoms, suppress recurrences and reduce the risk of transmission. Valacyclovir was discovered in 1988 and revolutionized the treatment of these infections by virtue of its less frequent dosing regimen, which promotes patient adherence. AREAS COVERED IN THIS REVIEW: This review focuses on the basic principles, mechanisms of action, safety and approved and off-label usage of valacyclovir in the immunocompetent and immunocompromised host. WHAT THE READER WILL GAIN: The reader will have available the current and most up-to-date information on the pharmacology of valacyclovir as well as its clinical use. TAKE HOME MESSAGE: Valacyclovir is a great alternative for the treatment of herpes infections. Now that its patent has expired, new cheaper formulations may start to appear.