Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on January 4th, 2026.
Valtrex, known generically as valacyclovir, is a widely prescribed antiviral medication. It’s primarily used to manage viral infections caused by herpes viruses, including genital herpes, cold sores (herpes labialis), and shingles (herpes zoster). Understanding the correct dosage is crucial to effectively control symptoms, speed recovery, and reduce the risk of transmission.
Valtrex works by inhibiting the replication of the herpes virus, thereby reducing the severity and duration of outbreaks. This mechanism of action is particularly beneficial for individuals who experience frequent recurrences of herpes simplex virus infections. In addition to its primary uses, Valtrex has shown effectiveness in preventing the transmission of genital herpes to uninfected partners when taken consistently, which can significantly improve the quality of life for those affected by this condition.
Engaging in open conversations about medication management and side effects can empower patients to take control of their health while ensuring they receive the most effective treatment possible.
This guide breaks down typical dosages, how to adjust doses for different conditions, and what to do if a dose is missed. Whether you are new to Valtrex or looking for a refresher, this information will help you use the medication safely and effectively.
Form |
Strength |
Typical Adult Dose |
Typical Children’s Dose |
Frequency |
Route |
Maximum Daily Dose |
|---|---|---|---|---|---|---|
Tablet |
500 mg |
500 mg to 1 g |
Weight-based, varies |
Once to three times daily |
Oral |
3 g/day |
For initial episodes of genital herpes, adults typically take 1 gram twice daily for 10 days. For recurrent outbreaks, the dose is usually 500 mg twice daily for 3 to 5 days. Suppressive therapy, which reduces the frequency of outbreaks, often involves 500 mg to 1 gram once daily.
Adults usually take 2 grams twice a day (taken 12 hours apart) at the first sign of a cold sore. This short course helps reduce symptom duration and severity.
The typical adult dose for shingles is 1 gram three times daily for 7 days. Early treatment is essential to minimize nerve pain and speed healing.
For children aged 2 years and older, the dose is weight-based, generally 20 mg/kg up to 1 gram, three times daily for 5 days.
Adult dosages depend heavily on the condition being treated. For many herpes infections, doses range between 500 mg and 1 gram, taken one to three times daily. The exact dose and duration are tailored to the severity of the infection and whether the treatment is for an initial outbreak, recurrent episode, or suppressive therapy.
It’s essential to follow the prescribed schedule closely. Taking Valtrex at evenly spaced intervals helps maintain adequate drug levels in the body.
Valtrex dosing in children is based on body weight and the specific infection. For chickenpox, the most common pediatric use, the dose is 20 mg/kg up to 1 gram, taken three times daily for 5 days. For other herpes infections, pediatric dosing should always be confirmed by a healthcare provider.
If a dose is missed, take it as soon as you remember. However, if it’s almost time for your next dose, skip the missed dose to avoid doubling up. Never take two doses at once. Maintaining consistent dosing is key to the medication’s effectiveness.
Valtrex is eliminated primarily through the kidneys. Patients with kidney problems may need dose adjustments to prevent accumulation and toxicity. Your healthcare provider will determine the appropriate dose based on kidney function tests.
While kidney function is the main factor affecting dose adjustments, always inform your doctor about other health conditions and medications to avoid interactions.
An overdose of Valtrex can cause symptoms such as nausea, vomiting, confusion, hallucinations, or seizures. If an overdose is suspected, seek emergency medical attention immediately. Always store medications safely and follow dosing instructions closely.
Valtrex should be used with caution in patients with kidney disease, and those who are pregnant or breastfeeding should consult their healthcare provider before use.
Take Valtrex with or without food, but drink plenty of fluids to stay hydrated.
Do not stop taking the medication early, even if symptoms improve.
Inform your healthcare provider about all other medications and supplements you are taking.
Use reliable telehealth services like Doctronic.ai to get personalized advice and connect with doctors if you have questions about your dosage or side effects.
Doctronic is a leading AI-powered healthcare platform that offers personalized medical guidance and telehealth visits with licensed doctors across all 50 states. If you need tailored advice on Valtrex dosing or want to discuss your symptoms and treatment options, Doctronic.ai provides fast, affordable, and convenient video visits 24/7. Their AI doctor remembers your medical history and synthesizes the latest peer-reviewed research to give you the most accurate information possible.
Yes, Valtrex can be taken with or without food. Staying hydrated is recommended while on the medication.
For best results, start taking Valtrex as soon as you notice symptoms or a suspected outbreak.
Daily suppressive therapy is standard for frequent herpes outbreaks, but should only be done under medical supervision.
Your doctor will adjust your dose based on kidney function to ensure safety.
Absolutely. Doctronic.ai offers AI-powered personalized medical advice and connects you with doctors for telehealth visits to answer your questions about Valtrex and other medications.
Valtrex is a powerful antiviral that requires careful dosing to be effective and safe. The right dose depends on your condition, age, and kidney function. Always follow your healthcare provider’s instructions and never hesitate to seek expert advice if you’re unsure about your medication. Doctronic.ai makes it easier than ever to get personalized care without leaving your home.
Understanding Valtrex Uses and DosagesValtrex, known generically as valacyclovir, is a widely prescribed antiviral medication. It’s primarily used to manage viral infections [...]
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