Valtrex® Information

What is Valtrex?

Valacyclovir or Valtrex is an anti viral drug used to treat infections such as herpes simplex - cold sores, genital herpes, shingles.  back to top

How It Works:

Valacyclovir or Valtrex is the pro drug of acyclovir, meaning that in the body it is converted to the active drug acyclovir. Acyclovir interferes with viral reproduction.

In shingles Valacyclovir or Valtrex reduces the fever, lesions, and shortens the duration of the infection. It is able to shorten the pain the occurs after the shingles have 100% cleared - the post herpetic neuralgia.  back to top

Side Effects:

Valacyclovir or Valtrex can cause nausea and headache. It also may be involved in kidney damage.  back to top

Cautions:

Because of the potential kidney problems, people with existing kidney damage should be careful using Valacyclovir or Valtrex.

Other problems may include nausea, headache, vomiting, diarrhea; AIDS patients on high dosages (8 gm/day) were more likely to experience thrombotic thrombocytopenic purpura/hemolytic uremic syndrome than immunocompetent patients.  back to top

Other Notes:

Valtrex is supplied as film-coated caplets containing 500 mg valacyclovir. The manufacturer recommends a dosage for herpes zoster of 1 g (two caplets) by mouth three times a day for 7 days. Patients should begin taking the drug at the earliest sign of shingles (the medication is most effective when started within 48 hours of the appearance of rash). Efficacy when treatment starts more than 72 hours after onset of rash has not been determined. Dosage modification may be required for patients with renal impairment and for the elderly (depending on renal function). Valacyclovir use has not been evaluated for children. Concomitant administration of cimetidine, probenecid, or both may reduce the rate but not the extent of conversion of valacyclovir to acyclovir   back to top