AntiviralPrescription only
Valaciclovir
Tablet
Quick Summary
Valaciclovir is absorbed better than aciclovir, so it's taken fewer times a day.
Shingles
Genital herpes
Cold sores
Medical Uses
Shingles: Started early.
Genital herpes: Outbreaks and suppression.
Cold sores: Short courses.
How it's taken
Take it as prescribed with plenty of water.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Headache
Common.
Nausea
Sometimes.
Kidney effects
Stay hydrated.
Interactions
Kidney-affecting medicines
Increase risk.
Critical Warnings
Kidney problems
Dose adjustment may be needed.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Valacyclovir: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine