Valacyclovir
Valtrex (valacyclovir) is an antiviral prescription medication used to treat infections caused by herpes viruses, including cold sores, genital herpes, and shingles. It works by stopping the virus from multiplying, which helps reduce symptoms and speeds healing of outbreaks. This medication can be used for both initial outbreaks and to suppress recurrent episodes.
Valtrex is an antiviral medication that treats herpes infections like cold sores, genital herpes, and shingles by stopping the virus from spreading.
Key facts at a glance
- RxNorm
- 152490
- Generic
- Valtrex
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Valtrex is FDA-approved to treat cold sores (herpes labialis) in adults and children, genital herpes outbreaks in adults, and shingles (herpes zoster). It is also used off-label for chickenpox in certain cases and may be prescribed for suppression of recurrent genital herpes episodes.
Valtrex contains valacyclovir, which converts to acyclovir in the body. Acyclovir inhibits viral DNA replication by blocking the viral DNA polymerase enzyme, preventing the herpes virus from multiplying and spreading to healthy cells.
Valtrex is most effective when started at the first sign of an outbreak. It does not cure herpes infections but helps manage symptoms and reduce the frequency of outbreaks. Common side effects include headache, nausea, and abdominal pain. Patients with kidney problems or weakened immune systems should use caution and be monitored by their healthcare provider.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 26, 2026. · Read our editorial policy