Valacyclovir
Valacyclovir is an antiviral medication used to treat infections caused by herpes viruses, including cold sores, genital herpes, and shingles. It works by stopping the growth and spread of the virus, helping to reduce symptoms and speed healing. It can also be used long-term to prevent recurring outbreaks.
An antiviral medication for treating and preventing herpes virus infections like cold sores, genital herpes, and shingles.
Key facts at a glance
- ATC
- J05AB11
- RxNorm
- 73645
- Generic
- Valacyclovir
- Class
- atc-j05
- Brands
- Valtrex
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- 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.
Treats cold sores (herpes labialis), genital herpes (initial and recurrent episodes), and shingles (herpes zoster). Also used for suppression of recurrent genital herpes and prevention of CMV disease in transplant patients.
Valacyclovir is a prodrug that converts to acyclovir in the body. It inhibits viral DNA replication by targeting the viral DNA polymerase enzyme, preventing the virus from multiplying and spreading to healthy cells.
Most effective when started at the first sign of an outbreak. Should stay hydrated while taking this medication. Not a cure for herpes—virus remains dormant in the body. Inform your doctor if you have kidney problems or a weakened immune system before use.
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 July 26, 2026. · Read our editorial policy