• Valaciclovir is used to treat viral infections.
  • Complete the full course of valaciclovir prescribed, otherwise your infection may re-occur.
  • Drink plenty of fluids while taking valaciclovir. It is important not to become dehydrated.

About valaciclovir

Type of medicine Antiviral
Used for Herpes zoster (causes shingles)
Herpes simplex (causes cold sores, genital herpes)
Prevention of cytomegalovirus disease following renal transplant
Also called Valtrex®
Available as Tablets

Valaciclovir is known as a pro-drug. Once inside the body it is broken down into the active ingredient aciclovir. Aciclovir works by preventing the herpes viruses from multiplying. This stops the growth of the virus.

Before taking valaciclovir

Before taking valaciclovir make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have liver or kidney problems.
  • If you are over 65 years of age.
  • If you are taking other medicines, including those available to buy without a prescription, herbal or complementary medicines.
  • If you have ever had an allergic reaction to this or to any other medicine.

How to take valaciclovir

  • Before beginning treatment, read the manufacturer's printed information leaflet.
  • Take valaciclovir exactly as directed by your doctor. Swallow the tablets whole with a drink of water. They can be taken before or after food.
  • Try to take valaciclovir at the same time(s) each day to avoid missing any doses. If you are taking more than one dose each day, spread your doses out evenly during the day.
  • If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a missed dose.
  • You must complete the prescribed course of valaciclovir, otherwise your infection may re-occur.

Getting the most from your treatment

  • You must drink plenty while taking valaciclovir. Do not let yourself become dehydrated.
  • Valaciclovir may cause your skin to become more sensitive to sunlight than it is usually. Try to avoid sunlight or use a suncream with a sun protection factor (SPF) of 15 or higher until you know how your skin reacts. Do not use sunbeds.
  • If you have been prescribed valaciclovir for genital herpes (a sexually transmitted disease), it is recommended that you wear a condom during sexual contact to prevent spreading the infection, even if treatment with valaciclovir has begun. You should not have sex however, if you have sores or blisters.
  • If you are having any treatment like an operation or dental treatment, tell the person carrying out the treatment that you are taking valaciclovir.
  • If you buy any medicines, check with a pharmacist that they are safe to take with valaciclovir.

Can valaciclovir cause problems?

Along with their useful effects, all medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Possible valaciclovir side-effects What can I do if I experience this?
Headache Ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor
Feeling or being sick, stomach ache Eat little and often. Stick to simple foods
Dizziness, tiredness Make sure your reactions are normal before driving, operating machinery or doing any other jobs which could be dangerous if you were not fully alert
Diarrhoea Drink plenty of water to replace lost fluids
Rash, itching If troublesome, let your doctor know

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store valaciclovir

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.