If you’ve been prescribed Valtrex (valacyclovir), the biggest question is probably “how much should I take?” Below we break down the most common dosing schedules so you can start treatment with confidence.
Cold sores (herpes labialis): The typical adult dose is 1 gram (1000 mg) taken twice a day, spaced about 12 hours apart. Most doctors tell you to start the first dose as soon as you notice tingling or a small sore, then finish the second dose 12 hours later. No more than two doses are needed.
Genital herpes – initial outbreak: For a first episode, adults usually get 500 mg twice daily for 10 days. If you have frequent recurrences, your doctor might suggest a suppressive regimen of 500 mg once daily to keep outbreaks at bay.
Shingles (herpes zoster): The standard adult plan is 1 gram taken three times a day for 7 days. Taking the doses every 8 hours helps keep the virus under control and can reduce pain faster.
Pediatric dosing: Children get valacyclovir based on weight, typically 20 mg per kilogram of body weight taken twice daily for cold sores or genital herpes. Always double‑check the exact amount with your pediatrician.
Taking Valtrex with food: You can take it with or without meals. If you experience stomach upset, a small snack may help.
If you miss a dose: Take it as soon as you remember unless it’s almost time for the next dose. In that case, skip the missed one—don’t double up.
Common side effects: Most people only feel mild nausea or headache. If you get severe dizziness, rash, or trouble breathing, call your doctor right away.
Remember, Valtrex works best when you start it early in the outbreak and finish the full course, even if symptoms improve quickly. Stopping early can let the virus bounce back.
If you have kidney problems, are pregnant, or take other medications that affect the kidneys, your doctor may adjust the dose. Always share a complete list of medicines with your prescriber.
Bottom line: The right Valtrex dose depends on what infection you’re treating, your age and weight, and any underlying health issues. Use the schedules above as a quick reference, but follow your doctor's specific instructions for safest results.
