If you’ve been prescribed Valtrex (valacyclovir), you probably want simple, clear info on how much to take and when. Below I list common adult doses for the usual conditions—shingles, genital herpes, and cold sores—plus quick safety tips so you don’t miss anything important. This is general information, not medical advice; talk to your doctor about the right dose for you.
Shingles (herpes zoster): Adults typically take 1 gram (1000 mg) three times a day for 7 days. Start treatment as soon as possible—ideally within 72 hours of the rash appearing—to help reduce pain and speed healing.
Genital herpes – first episode: A common dose is 1 gram twice a day for 7–10 days. Your doctor may adjust this based on symptoms and health history.
Genital herpes – recurrent outbreaks: Many people use either 500 mg twice daily for 3 days, or 1 gram twice in one day (taken 12 hours apart). Another option for frequent outbreaks is daily suppressive therapy—typically 500 mg once daily, or 1 gram once daily for people who need stronger suppression. Your provider will advise which fits your case.
Cold sores (herpes labialis): A fast one-day course is common—2 grams taken now and 2 grams again 12 hours later (total 4 grams in one day). The key is to start at the first tingling or symptom.
Kidneys matter. Valtrex is cleared by the kidneys, so people with reduced kidney function need lower doses. If you have kidney disease, diabetes, or take other medications that affect the kidneys, tell your doctor—dosing will change.
Take with water. Valtrex can be taken with or without food. Drink plenty of fluids while on the medicine to help your kidneys handle the drug.
Side effects are usually mild: headache, nausea, and stomach upset are most common. Serious side effects—confusion, severe dizziness, sudden changes in urination—need urgent care. If you notice weird symptoms, stop the medicine and contact your provider.
Pregnancy and breastfeeding: If you’re pregnant or breastfeeding, talk to your doctor before starting Valtrex. The benefits and risks need discussion for your situation.
Timing matters. For shingles and cold sores, earlier treatment usually works better. For genital herpes, follow the exact course your doctor prescribes—don’t stop early just because symptoms improve.
Special groups: Pediatric dosing is weight-based and different from adults. Older adults may need adjustments. Always follow the prescription and ask your prescriber if anything is unclear.
Final note: Use this guide as a quick reference. Your doctor knows your health history and will choose the safest, most effective dose for you.
