Patient leaflet - Valtrex 500 mg film-coated tablets
1. WHAT VALTREX® IS AND WHAT IT IS USED FOR
Valtrex® belongs to a group of medicines called antivirals. It works by killing or stopping the growth of viruses called herpes simplex (HSV), varicella zoster (VZV) and cytomegalovirus (CMV).
Valtrex® can be used to:
- treat shingles (in adults)
treat HSV infections of the skin and genital herpes (in adults and adolescents over 12 years old). It is also used to help prevent these infections from returning.
- treat cold sores (in adults and adolescents over 12 years old)
- prevent infection with CMV after organ transplants (in adults and adolescents over 12 years old)
- treat and prevent HSV infections of the eye that continue to come back (in adults and adolescents over 12 years old)
2. WHAT YOU NEED TO KNOW BEFORE YOU TAKE VALTREX®
Do not take Valtrex®
- if you are allergic to valaciclovir or aciclovir or any of the other ingredients of this medicine (listed in Section 6).
➔Don’t take Valtrex® if the above applies to you. If you are not sure, talk to your doctor or pharmacist before taking Valtrex®.
Warnings and precautions
Talk to your doctor or pharmacist before taking Valtrex® if:
- you have ever developed a severe skin rash or skin peeling, blistering and/or mouth sores after taking valaciclovir or aciclovir
- you have kidney problems
- you have liver problems
- you are over 65 years of age
- your immune system is weak
If you are not sure if the above apply to you, talk to your doctor or pharmacist before taking Valtrex®.
Take special care with Valtrex® – Important Information:
Valtrex® can cause severe skin reactions. Stop using Valtrex® and seek medical attention immediately if you notice any of the symptoms of severe skin reactions described in section 4.
Prevent passing genital herpes on to others
If you are taking Valtrex® to treat or prevent genital herpes, or you have had genital herpes in the past, you should still practice safe sex, including the use of condoms. This is important to prevent you passing the infection on to others. You should not have sex if you have genital sores or blisters.
Other medicines and Valtrex®
Tell your doctor or pharmacist if you are taking or have recently taken any other medicines. This includes medicines obtained without a prescription, including herbal medicines.
Tell your doctor or pharmacist if you are taking any other medicines that affect the kidneys. These include: aminoglycosides, organoplatinum compounds, iodinated contrast media, methotrexate, pentamidine, foscarnet, ciclosporin, tacrolimus, cimetidine and probenecid. Always tell your doctor or pharmacist about other medicines if you are taking Valtrex® for treatment of shingles or after having an organ transplant.
Pregnancy and breast-feeding
Valtrex® is not usually recommended for use during pregnancy. If you are pregnant, or think you could be, or if you are planning to become pregnant, don’t take Valtrex® without checking with your doctor. Your doctor will weigh up the benefit to you against the risk to your baby of taking Valtrex® while you’re pregnant or breastfeeding.
Driving and using machines
Valtrex® can cause side effects that affect your ability to drive. ➔Don’t drive or use machines unless you are sure you’re not affected.
3. HOW TO TAKE VALTREX®
Always take this medicine exactly as your doctor has told you. You should check with your doctor or pharmacist if you are not sure. The dose that you should take will depend on why your doctor has prescribed Valtrex® for you. Your doctor will discuss this with you. Treatment of shingles
- The usual dose is 1000 mg (one 1000 mg tablet or two 500 mg tablets) three times a day.
- You should take Valtrex® for seven days.
Treatment of cold sores
- The usual dose is 2000 mg (two 1000 mg tablets or four 500 mg tablets) twice a day.
- The second dose should be taken 12 hours (no sooner than 6 hours) after the first dose.
- You should take Valtrex® for one day (two doses) only. Treatment of HSV infections of the skin and genital herpes
- The usual dose is 500 mg (one 500 mg tablet or two 250 mg tablets) twice a day.
- For the first infection you should take Valtrex® for five days or for up to ten days if your doctor tells you to. For recurrent infection the duration of treatment is normally 3-5 days.
Helping to prevent HSV infections from returning after you have had them
- The usual dose is one 500 mg tablet once a day.
- Some people with frequent recurrences may benefit from taking one 250 mg tablet twice a day.
- You should take Valtrex® until your doctor tells you to stop. To stop you being infected with CMV (Cytomegalovirus)
- The usual dose is 2000 mg (two 1000 mg tablets or four 500 mg tablets) four times a day.
- You should take each dose about 6 hours apart.
- You will usually start taking Valtrex® as soon as possible after your surgery.
- You should take Valtrex® for around 90 days after your surgery, until your doctor tells you to stop.
Your doctor may adjust the dose of Valtrex® if:
- you are over 65 years of age
- you have a weak immune system
- you have kidney problems.
➔Talk to your doctor before taking Valtrex® if any of the above apply.
Taking this medicine
- Take this medicine by mouth.
- Swallow the tablets whole with a drink of water.
- Take Valtrex® at the same time each day.
- Take Valtrex® according to instructions from your doctor or pharmacist.
People over 65 years of age or with kidney problems
It is very important while you are taking Valtrex® that you drink water regularly during the day. This will help to reduce side effects that can affect the kidney or nervous system. Your doctor will closely monitor you for signs of these. Nervous system side effects might include feeling confused or agitated, or feeling unusually sleepy or drowsy.
If you take more Valtrex® than you should
Valtrex® is not usually harmful, unless you take too much over several days. If you take too many tablets you may feel sick, vomit, get kidney problems, may be confused, agitated, feel less aware, see things that aren’t there, or become unconscious. Talk to your doctor or pharmacist if you take too much Valtrex®. Take the medicine pack with you.
If you forget to take Valtrex®
- If you forget to take Valtrex®, take it as soon as you remember. However, if it is nearly time for your next dose, skip the missed dose. Do not take a double dose to make up for a forgotten dose.
4. POSSIBLE SIDE EFFECTS
Like all medicines, this medicine can cause side effects, although not everybody gets them.
Conditions you need to look out for:
➔Stop using Valtrex® and seek medical attention immediately if you notice any of the following symptoms:
Severe allergic reactions (anaphylaxis). These are rare in people taking Valtrex®. Rapid development of symptoms including:
- flushing, itchy skin rash
- swelling of the lips, face, neck and throat, causing difficulty in breathing (angiodema)
- fall in blood pressure leading to collapse.
Serious skin reactions.
These are very rare in people taking Valtrex®. Signs include:
- widespread rash, high body temperature and enlarged lymph nodes (DRESS syndrome or drug hypersensitivity syndrome).
- a red, scaly widespread rash with bumps under the skin and blisters accompanied by fever. The symptoms usually appear at the initiation of treatment [acute generalised exanthematous pustulosis (AGEP)].
These frequencies are not known, signs include:
- reddish non-elevated, target-like or circular patches on the trunk, often with central blisters, skin peeling, ulcers of mouth, throat, nose, genitals and eyes. These serious skin rashes can be preceded by fever and flu-like symptoms [Stevens-Johnson syndrome (SJS)/ toxic epidermal necrolysis (TEN)].
The following side effects may also happen with this medicine:
Very Common (may affect more than 1 in 10 people):
- headache
Common (may affect up to 1 in 10 people)
- feeling sick
- dizziness
- vomiting
- diarrhoea
- skin reaction after exposure to sunlight (photosensitivity).
- rash
- itching (pruritus)
Uncommon (may affect up to 1 in 100 people)
- feeling confused
- seeing or hearing things that aren’t there (hallucinations)
- feeling very drowsy
- tremors
- feeling agitated
These nervous system side effects usually occur in people with kidney problems, the elderly or in organ transplant patients taking high doses of 8 grams or more of Valtrex® a day. They usually get better when Valtrex® is stopped or the dose reduced.
Other uncommon side effects:
- shortness of breath (dyspnoea)
stomach discomfort
- rash, sometimes itchy, hive-like rash (urticaria)
- low back pain (kidney pain)
- blood in urine (haematuria)
Uncommon side effects that may show up in blood tests:
- reduction in the number of white blood cells (leucopenia)
- reduction in the number of blood platelets which are cells that help blood to clot (thrombocytopenia)
- increase in substances produced by the liver.
Rare (may affect up to 1 in 1,000 people)
- unsteadiness when walking and lack of coordination (ataxia)
- slow, slurred speech (dysarthria)
- fits (convulsions)
- altered brain function (encephalopathy)
- unconsciousness (coma)
- confused or disturbed thoughts (delirium)
These nervous system side effects usually occur in people with kidney problems, the elderly or in organ transplant patients taking high doses of 8 grams or more of Valtrex® a day. They usually get better when Valtrex® is stopped or the dose reduced.
Other rare side effects:
- kidney problems where you pass little or no urine.
Frequency Not Known (cannot be estimated from the available data)
- an inflammation of the kidneys (tubulointerstitial nephritis)
Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.
5. HOW TO STORE VALTREX®
- Keep out of the sight and reach of children.
- Do not use this medicine after the expiry date which is stated on the label after EXP. The expiry date refers to the last day of that month.
- Do not store above 30°C.
- If the tablets become discoloured or show any other signs of deterioration, you should seek the advice of your pharmacist who will tell you what to do.
- Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help to protect the environment.
6. CONTENTS OF THE PACK AND OTHER INFORMATION
The active substance is valaciclovir. Each tablet contains 500 mg of valaciclovir (as valaciclovir hydrochloride).
The other ingredients are:
Tablet core
Microcrystalline cellulose, crospovidone, povidone K90, magnesium stearate, silica colloidal anhydrous.
Film coat
Hypromellose, titanium dioxide, macrogol 400, polysorbate 80, carnauba wax.
What Valtrex® look like and contents of the pack
Valtrex® tablets are contained in polyvinyl chloride/aluminium foil blister packs.
Valtrex® is supplied in cartons containing 10 film-coated tablets. They are white and marked with “GX CF1” on one side.
Manufactured by Glaxo Wellcome S.A., Avenida de Extremadura 3, 09400, Aranda de Duero, Burgos, Spain.
Procured from within the EU and repackaged by the Product Licence Holder Beachcourse Ltd., Unit 2-3, Townsend Industrial Estate, Waxlow Road, London, NW10 7NU.
Revision date: 02.07.2026
PL 16378/1274 POM
Valtrex® is a registered trademark of Glaxo Group Limited.
Blind or partially sighted? Is this leaflet hard to see or read? Phone Beachcourse, Tel: 020 8896 9054 for help. Ref. number: 1274/V1