No efficacy evaluations were conducted in any of the 3 trials.Trial 1 was a single‑dose pharmacokinetic, multiple‑dose safety trial in 27 pediatric subjects aged 1 to less than 12 years with clinically suspected varicella‑zoster virus (VZV) infection Trial 2 was a single‑dose pharmacokinetic and safety trial in pediatric subjects aged 1 month to less than 6 years who had an active herpes virus infection or who were at risk for herpes virus infection. Elderly patients are more likely to have central nervous system adverse reactions. The only adverse reaction reported in greater than 10% of pediatric subjects aged less than 18 years was headache.Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.In clinical trials for the treatment of cold sores, the adverse reactions reported by subjects receiving Valtrex 2 grams twice daily (n = 609) or placebo (n = 609) for 1 day, respectively, included headache (14%, 10%) and dizziness (2%, 1%). In biochemical assays, acyclovir triphosphate inhibits replication of α-herpes viral DNA. There are no data on the safety or effectiveness of chronic suppressive therapy of more than 6 months’ duration in HIV-1−infected patients.There are no data on treatment initiated more than 72 hours after onset of the zoster rash. The median time to lesion healing was about 4½ days in both treatment groups. Outcomes for the overall trial population are shown in Subjects with 9 or fewer recurrences per year showed comparable results with Valtrex 500 mg once daily.In a second trial, 293 HIV‑1−infected adults on stable antiretroviral therapy with a history of 4 or more recurrences of ano‑genital herpes per year were randomized to receive either Valtrex 500 mg twice daily (n = 194) or matching placebo (n = 99) for 6 months. Each subject was dosed with valacyclovir oral suspension, 20 mg/kg 3 times daily for 5 days. The mean projected daily acyclovir exposures in pediatric subjects across all age‑groups (1 to less than 12 years) were lower (CValtrex tablets (blue, film‑coated, capsule‑shaped tablets printed with “Valtrex 500 mg”) containing 556.2 mg of valacyclovir hydrochloride equivalent to 500 mg valacyclovir.Valtrex tablets (blue, film‑coated, capsule‑shaped tablets, with a partial scorebar on both sides, printed with “Valtrex 1 gram”) containing 1.112 grams of valacyclovir hydrochloride equivalent to 1 gram of valacyclovir.Store at 15° to 25°C (59° to 77°F). The Acyclovir Registry documented outcomes of 1,246 infants and fetuses exposed to acyclovir during pregnancy (756 with earliest exposure during the first trimester, 197 during the second trimester, 291 during the third trimester, and 2 unknown). Cautions. This is accomplished in 3 ways: 1) competitive inhibition of viral DNA polymerase, 2) incorporation and termination of the growing viral DNA chain, and 3) inactivation of the viral DNA polymerase. There are insufficient data on the use of valacyclovir regarding miscarriage or adverse maternal or fetal outcomes In animal reproduction studies, no evidence of adverse developmental outcomes was observed with valacyclovir when administered to pregnant rats and rabbits at system exposures (AUC) 4 (rats) and 7 (rabbits) times the human exposure at the maximum recommended human dose (MRHD) The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. During hemodialysis, the half-life of acyclovir after administration of Valtrex is approximately 4 hours. Acyclovir systemic exposures in pediatric subjects following valacyclovir oral suspension were compared with historical acyclovir systemic exposures in immunocompetent adults receiving the solid oral dosage form of valacyclovir or acyclovir for the treatment of recurrent genital herpes. Select one or more newsletters to continue. Approximately one‑third of acyclovir in the body is removed by dialysis during a 4‑hour hemodialysis session. Treatment with Valtrex should be stopped immediately if clinical signs, symptoms, and laboratory abnormalities consistent with TTP/HUS occur.Cases of acute renal failure have been reported in:In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored Central nervous system adverse reactions, including agitation, hallucinations, confusion, delirium, seizures, and encephalopathy, have been reported in both adult and pediatric patients with or without reduced renal function and in patients with underlying renal disease who received higher-than-recommended doses of Valtrex for their level of renal function.

In subjects aged less than 50 years, no difference was found with respect to the duration of pain after healing (post‑herpetic neuralgia) between the recipients of Valtrex and placebo. In the presence of metabolic activation (76% to 88% conversion to acyclovir), valacyclovir was mutagenic.Valacyclovir was mutagenic in a mouse micronucleus assay.Valacyclovir did not impair fertility or reproduction in male or female rats at acyclovir exposures (AUC) 6 times higher than in humans given the MRHD. You can ask your healthcare provider or pharmacist for information about Valtrex that is written for health professionals.Trademark is owned by or licensed to the GSK group of companies.This Patient Information has been approved by the U.S. Food and Drug Administration.Equivalent to 556.2 mg valacyclovir hydrochloride per tablet.See prescribing information for dosage information.Equivalent to 1.112 grams valacyclovir hydrochloride per tablet.See prescribing information for dosage information.The easiest way to lookup drug information, identify pills, check interactions and set up your own personal medication records. Acyclovir bioavailability from the administration of Valtrex is not altered by administration with food (30 minutes after an 873 Kcal breakfast, which included 51 grams of fat).Acyclovir pharmacokinetic parameter estimates following administration of Valtrex to healthy adult volunteers are presented in There is no accumulation of acyclovir after the administration of valacyclovir at the recommended dosage regimens in adults with normal renal function.The plasma elimination half‑life of acyclovir typically averaged 2.5 to 3.3 hours in all trials of Valtrex in subjects with normal renal function.Following administration of Valtrex to subjects with ESRD, the average acyclovir half‑life is approximately 14 hours.