Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on January 4th, 2026.
Valacyclovir is a prescription antiviral drug designed to combat infections caused by herpes viruses. It’s commonly prescribed for conditions such as cold sores (herpes labialis), genital herpes, and shingles (herpes zoster). The medication works by slowing the growth and spread of the virus, helping the body fight the infection more effectively.
Because valacyclovir targets viral replication, it’s most effective when taken early in the course of an outbreak. However, it’s also used as a suppressive therapy to reduce the frequency of recurrent outbreaks in chronic cases. Understanding the correct dosage and timing is crucial to maximizing benefits and minimizing side effects.
Form |
Strength |
Typical Adult Dose |
Typical Children’s Dose |
Frequency |
Route |
Maximum Daily Dose |
|---|---|---|---|---|---|---|
Tablet |
500 mg |
500 mg to 1 g |
20 mg/kg (up to 1 g) |
Once to three times daily |
Oral |
4 g/day |
For adults experiencing cold sores, the usual dose is 2 grams taken twice in one day, approximately 12 hours apart. This short course helps reduce healing time and discomfort. Children under 12 typically do not use valacyclovir for cold sores unless directed by a doctor.
Initial episodes of genital herpes require 1 gram twice daily for 10 days. For recurrent outbreaks, the dose is usually 500 mg twice daily for 3 days. Suppressive therapy to reduce outbreak frequency involves 500 mg to 1 gram once daily, depending on the severity and frequency of episodes.
Adults with shingles are generally prescribed 1 gram three times daily for 7 days. Early treatment is essential to reduce pain and speed recovery. Children’s dosing is less standard but typically adjusted by weight and prescribed by a healthcare provider.
Adult dosing depends heavily on the infection being treated. For most herpes-related conditions, doses range from 500 mg to 1 gram, taken one to three times daily. Your healthcare provider will determine the exact frequency and duration based on the severity of your infection and your overall health.
For example, a typical adult dose for genital herpes outbreaks is 1 gram twice daily for 10 days, while suppressive therapy might be 500 mg once daily. Shingles treatment usually requires a higher dose of 1 gram three times daily for a week.
Valacyclovir dosing in children is generally weight-based and less frequently prescribed than in adults. For children 12 years and older, doses often mirror adult dosing but are adjusted for weight and specific condition. For younger children, dosing and use should be strictly under medical supervision.
For example, in treating chickenpox (varicella), valacyclovir may be dosed at 20 mg/kg up to a maximum of 1 gram taken three times daily for 5 days. Always consult a healthcare professional for pediatric dosing.
If you miss a dose, take it as soon as you remember. If it’s almost time for your next dose, skip the missed one-do not double up. Taking more than the prescribed dose can increase the risk of side effects. Maintaining a consistent schedule helps keep the medication effective.
Valacyclovir is primarily eliminated through the kidneys. Patients with impaired kidney function require dosage adjustments to prevent drug accumulation and toxicity. Your doctor may reduce the dose or extend the interval between doses based on your kidney health.
While kidney function is the main factor affecting valacyclovir dosing, always inform your healthcare provider about other medical conditions or medications you are taking to avoid interactions or complications.
Taking too much valacyclovir can lead to serious side effects such as confusion, hallucinations, seizures, or kidney problems. Seek emergency medical attention if you suspect an overdose. Common side effects include headache, nausea, and abdominal pain, but severe reactions are rare when taken as prescribed.
Always follow your doctor’s instructions and never adjust your dose without consulting a healthcare professional. If you experience unusual symptoms, contact your provider immediately.
Take valacyclovir with or without food, but drink plenty of fluids to stay hydrated.
Complete the prescribed course in full, even if symptoms improve early.
Avoid sexual contact during active genital herpes outbreaks to prevent transmission.
Store the medication at room temperature away from moisture and heat.
Inform your doctor if you are pregnant, breastfeeding, or have other health conditions.
Personalizing your valacyclovir dosage can be complex, especially when factoring in your medical history and kidney function. Doctronic.ai offers an AI-powered doctor that synthesizes the latest medical research to provide tailored dosage information quickly and accurately. Over 10 million people have trusted Doctronic for their healthcare questions, enjoying fast, personal, and modern medical advice.
If you have questions about your valacyclovir dose or need a prescription or telehealth consultation, visit Doctronic.ai. Their licensed doctors are available 24/7 to help you get the proper treatment without the hassle of traditional appointments.
Valacyclovir can interact with some medications, especially those affecting kidney function. Always tell your doctor about all medications and supplements you are taking to avoid interactions.
Valacyclovir is generally considered safe during pregnancy but should only be used when clearly needed and prescribed by a healthcare provider.
For best results, start valacyclovir as soon as you notice symptoms or at the earliest sign of an outbreak.
No, valacyclovir does not cure herpes but helps control outbreaks and reduce symptoms.
Most side effects are mild. If you experience severe or unusual symptoms, contact your healthcare provider immediately.
Telehealth services like Doctronic.ai provide fast access to licensed doctors who can evaluate your condition and, when appropriate, prescribe valacyclovir.
Valacyclovir remains a cornerstone treatment for herpesvirus infections, with dosing tailored to the specific condition and patient needs. Following prescribed doses, understanding how to handle missed doses, and adjusting for kidney function are key to safe and effective treatment. When in doubt, personalized advice from healthcare professionals, primarily through convenient telehealth platforms like Doctronic.ai, can make all the difference in your care.
Understanding Valacyclovir Uses and DosagesValacyclovir is a prescription antiviral drug designed to combat infections caused by herpes viruses. It’s commonly prescribed for [...]
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