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

Valtrex is the brand name for valacyclovir, a common antiviral used for herpes viruses. You’ll see it for cold sores, genital herpes, and shingles. It’s a prodrug — your body turns it into acyclovir, which stops the virus from multiplying. That means it eases symptoms, shortens outbreaks, and can lower how often outbreaks happen when taken daily as suppression therapy.

How Valtrex works and when to start it

Valtrex works best when you start early. For cold sores, begin at the first tingle or spot; for genital herpes, start as soon as you notice symptoms or contact your doctor at the first sign; for shingles, start within 72 hours of the rash appearing. Early use cuts the length and pain of an outbreak. If you’re using it regularly to prevent outbreaks, your doctor will set the schedule based on how often you get them.

Dosing, side effects, and safety tips

Typical adult dosing (follow your prescriber’s instructions):

• Genital herpes, episodic: 500 mg twice daily for 3 days, or 1 g twice daily for 1 day (depending on the prescription).
• Genital herpes, suppressive: often 500 mg once daily; 1 g once daily may be used for frequent recurrences.
• Shingles (herpes zoster): 1 g three times daily for 7 days.
• Cold sores (herpes labialis): short, high-dose regimens started at first sign—follow label or doctor’s order.

Common side effects are headache, nausea, stomach pain, and dizziness. Less common but serious issues include kidney problems and confusion or hallucinations, especially in older adults or people with kidney disease. Drink enough water while on Valtrex and tell your doctor if you have kidney issues, are elderly, or take other medications that affect the kidneys.

Avoid driving or heavy machinery if you feel dizzy or confused. If you’re pregnant, breastfeeding, or trying to get pregnant, talk with your healthcare provider before taking Valtrex. Also mention all other medicines you take—some drugs can change how Valtrex affects your kidneys.

Valtrex requires a prescription in most places. If you consider buying it online, use licensed pharmacies only and verify a pharmacist can consult with you. Beware very low prices from unverified sites—fake or unsafe medicines are a real risk. If you’re unsure, ask your local pharmacist for help or request a prescription transfer to a reputable online pharmacy.

Short, practical checklist: start treatment early, follow the exact dose your doctor prescribes, stay hydrated, report new or severe side effects immediately, and never mix with unknown online sources. That keeps you safer and helps Valtrex do its job faster.