Valacyclovir: How It Works and When to Use It

Valacyclovir (Valtrex) is an antiviral that turns into acyclovir in your body. It stops the herpes virus from multiplying, which shortens outbreaks and lowers symptoms. People use it for cold sores, genital herpes, and shingles. Start treatment as soon as you notice symptoms — that’s when it helps most.

Here’s a quick rule: the earlier you begin, the better the outcome. If you wait until lesions are well established, valacyclovir can still help with pain and healing time, but the benefit is smaller.

How to take Valacyclovir

Dosage depends on the condition and whether it’s an initial attack, a recurrence, or suppressive therapy:

- Cold sores (herpes labialis): A common short regimen is 2 grams taken twice, 12 hours apart, when a prodrome or first sign appears.

- Genital herpes: Initial episode often treated with 1 gram twice daily for 10 days. For repeat outbreaks, 500 mg twice daily for 3 days is typical. For daily suppressive use, 500 mg to 1 gram once daily may be prescribed.

- Shingles (herpes zoster): Usually 1 gram three times daily for 7 days.

Always follow your prescriber’s instructions. If you have kidney problems, dosing changes are needed. Take tablets with water and stay hydrated during treatment — it helps protect your kidneys.

Side effects, risks, and interactions

Most people tolerate valacyclovir well. Common side effects are headache, nausea, stomach pain, and sometimes dizziness. Serious problems are rare but include reduced kidney function and confusion, especially in older adults or people with kidney disease.

Key safety points: check kidney function if you have chronic kidney disease, are elderly, or take other drugs cleared by the kidneys. Combining valacyclovir with drugs that affect kidney filtration can raise blood levels — tell your doctor about NSAIDs, gentle diuretics, or probenecid.

If you notice rash, swelling, sudden changes in urination, severe headache, hallucinations, or confusion, stop the drug and contact a healthcare provider right away.

Valacyclovir won’t cure herpes — the virus stays in your body. But it lowers how long outbreaks last, reduces pain, and can lower transmission risk when used as suppressive therapy. For people with frequent or severe outbreaks, daily suppressive therapy often makes life easier.

Buying online? Use licensed pharmacies and get a real prescription. If something seems unusually cheap or the site won’t verify a prescription, walk away. Your safety matters more than a small discount.

If you’re unsure whether valacyclovir is right for you, talk to your doctor or pharmacist. They’ll consider your kidney function, other meds, pregnancy or breastfeeding status, and how often you get outbreaks. With the right dose and simple precautions, valacyclovir is a practical, effective tool for managing herpes-related conditions.