Valaciclovir is used to treat shingles, susceptible viral infections of the skin and genitals, cold sores, prevent viral infections after organ transplants, treat and prevent viral infections of the eye. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.

This medication is also known as “valacyclovir“

What is this medication for?

It is an antiviral medication used to treat shingles, susceptible viral infections of the skin and genitals, cold sores, prevent viral infections after organ transplants, treat and prevent viral infections of the eye. The medication works by killing or stopping the growth of the viruses.

How should I take/use this medication?

  • Do not stop taking your medication without checking with your healthcare professional.
  • You may take this medication with or without food.
  • Swallow the tablets whole with a drink of water
  • It is very important that you drink water regularly while you are taking the medication

What should I do if I forget to take/use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take?

Inform your healthcare professional if:

  • You are allergic to this medication or any of the other ingredients of this medication
  • You are pregnant, planning to become pregnant, or breastfeeding (remove if not needed)
  • Do not drive, use machinery or do anything else that could be dangerous if you are dizzy or are not alert

What are some common side-effects of this medication?

  • Headache
  • Rash, skin itchiness
  • Nausea, vomiting, diarrhoea, abdominal pain
  • Skin reaction after exposure to sunlight
  • Feeling unwell
  • Dizziness

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

Some of these side effects include:

  • Kidney problem: Unable to pass urine, change in urine volume, blood in urine
  • Feeling confused, change in behaviour, mood changes
  • Seeing or hearing things that are not present
  • Slow, slurred speech
  • Seizures, tremors
  • Unsteadiness when walking and lack of coordination

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately

What food or medication should I avoid when I take this medication?

This medication may reduce the effects of certain vaccines and should be avoided. Other medications may increase the risks of this medication’s kidney-related side effects. You should therefore avoid taking these medications together. Consult your healthcare professionals for advice on the suitability of this medication with your other medications

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How should I throw away this medication safely?

Pack the medication into a bag and bring it back to the pharmacy where you received the medication from.



Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on April 2024

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