Valacyclovir Dosing for Viral Flare-Ups

Introduction to Valacyclovir Treatment

The Centers for Disease Control and Prevention recommends valacyclovir 500 mg twice daily for 5 days for herpes simplex virus (HSV) recurrent episodes, initiated at the first sign of prodrome or lesions 1, 2
For patients with normal immune function, valacyclovir 1000 mg once daily is recommended for suppressive therapy, with a reduction in recurrence frequency by ≥75% 1, 2

The Centers for Disease Control and Prevention recommends valacyclovir 500 mg orally twice daily for 5 days for episodic treatment of HSV genital herpes recurrent episodes, with treatment initiated at the first sign of prodrome or genital lesions 1, 2
Patients should be provided with medication or a prescription in advance to enable immediate treatment initiation, and treatment must be initiated at the first sign of prodrome or genital lesions for maximum efficacy 1, 2

For any severe HSV or VZV infection with complications, the Centers for Disease Control and Prevention recommends IV acyclovir 5-10 mg/kg every 8 hours for 5-7 days or until clinical resolution 1, 2, 3

The Centers for Disease Control and Prevention notes that therapy is most effective when initiated within 48 hours of symptom onset for both HSV and VZV, and for recurrent HSV, treatment at prodrome provides maximum benefit 1, 2, 4
Suppressive therapy reduces but does not eliminate asymptomatic viral shedding, and patients should be counseled that transmission can occur even during asymptomatic periods 1, 2, 5, 4

For severe disease with complications, such as disseminated infection, pneumonitis, hepatitis, or CNS involvement, the Centers for Disease Control and Prevention recommends using IV acyclovir 5-10 mg/kg every 8 hours for 5-7 days or until clinical resolution instead of oral valacyclovir, as stated in the MMWR Recommendations and Reports 6
The CDC advises against valacyclovir doses of 8 grams per day in immunocompromised patients due to the risk of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome, as reported in the MMWR Recommendations and Reports 6

For acyclovir-resistant HSV, the MMWR Recommendations and Reports suggests using IV foscarnet 40 mg/kg every 8 hours until clinical resolution 6
All acyclovir-resistant HSV strains are also resistant to valacyclovir, according to the MMWR Recommendations and Reports 6