Valtrex (valacyclovir): what it treats and how to use it

Valtrex is the brand name for valacyclovir, an oral antiviral many doctors prescribe for herpes viruses. People use it for shingles (herpes zoster), genital herpes, and cold sores. It doesn't cure the virus, but it shortens outbreaks, reduces pain, and helps sores heal faster.

How Valtrex is usually taken

Dosing depends on the problem and whether you're treating an outbreak or taking it every day to prevent them. Common regimens seen in clinic practice are:

- Shingles: 1 gram (1000 mg) three times a day for 7 days.
- Genital herpes (initial outbreak): 1 gram twice a day for 7–10 days.
- Genital herpes (recurrent): often 500 mg twice daily for 3 days, or 1 gram twice in a single day depending on timing.
- Cold sores (herpes labialis): a one-day course of 2 grams taken twice 12 hours apart at the first sign of a cold sore.
- Suppressive therapy (to reduce recurrences): commonly 500 mg or 1 gram once daily, depending on how often outbreaks occur.

Always follow your prescriber's exact instructions. If you have kidney problems, your doctor will lower the dose because valacyclovir is cleared by the kidneys.

Safety tips, side effects, and when to call a doctor

Common side effects are headache, nausea, stomach pain, and dizziness. Most people tolerate Valtrex well. Serious problems are rare but include confusion, agitation, severe kidney problems, or allergic reaction. Older adults and people with poor kidney function are at higher risk for confusion or swelling.

Drink water while taking Valtrex to help your kidneys clear the drug. Avoid taking it with other medicines that harm the kidneys without checking with your prescriber. One known interaction is with probenecid, which can raise valacyclovir levels; your doctor will adjust doses if needed.

If you’re pregnant or breastfeeding, tell your doctor. Valacyclovir is used in pregnancy when benefits outweigh risks, but decisions should be personalized. If you notice swelling, trouble urinating, severe rash, high fever, or mental changes, stop the medicine and seek medical help right away.

Missed dose? Take it as soon as you remember unless it’s almost time for the next dose. Don’t double up. Store Valtrex at room temperature, away from moisture and heat.

Questions you can ask your prescriber: Do I need suppressive therapy? How will Valtrex affect my other medications? Is it safe for my kidneys? Getting answers helps you use the drug safely and reduce future outbreaks.

Valtrex can make outbreaks shorter and less painful when used correctly. Keep communication open with your doctor, report unusual symptoms fast, and follow dosing tailored to your health.