Valtrex

Generic name: valacyclovir
Drug class: Purine nucleosides

Medically reviewed by A Ras MD.

What is Valtrex?

Valtrex is a prescription antiviral medicine. Valtrex lowers the ability of herpes viruses to multiply in your body.

Valtrex is used in adults: to treat cold sores (also called fever blisters or herpes labialis), shingles (also called herpes zoster), genital herpes outbreaks in adults with normal immune systems, to control genital herpes outbreaks in adults infected with the human immunodeficiency virus (HIV-1) with CD4+ cell count greater than 100 cells/mm3, with safer sex practices to lower the chances of spreading genital herpes to others. Even with safer sex practices, it is still possible to spread genital herpes.

Valtrex used daily with the following safer sex practices can lower the chances of passing genital herpes to your partner.

Do not have sexual contact with your partner when you have any symptom or outbreak of genital herpes.

Use a condom made of latex or polyurethane whenever you have sexual contact.

Valtrex is used in children to treat cold sores (for children aged greater than or equal to 12 years), to treat chickenpox (for children aged 2 to less than 18 years). Valtrex does not cure herpes infections (cold sores, chickenpox, shingles, or genital herpes). The efficacy of Valtrex has not been studied in children who have not reached puberty.

Description

VALTREX (valacyclovir hydrochloride) is the hydrochloride salt of the L‑valyl ester of the antiviral drug acyclovir.

VALTREX tablets are for oral administration. Each tablet contains 556.2 mg or 1.112 grams of valacyclovir hydrochloride equivalent to 500 mg or 1 gram of valacyclovir, respectively, and the inactive ingredients carnauba wax, colloidal silicon dioxide, crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, and titanium dioxide. The blue, film‑coated tablets are printed with edible white ink.

The chemical name of valacyclovir hydrochloride is L-valine, 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy]ethyl ester, monohydrochloride. It has the following structural formula:

valacyclovir hydrochloride chemical structure

Valacyclovir hydrochloride is a white to off-white powder with the molecular formula C13H20N6O4•HCl and a molecular weight of 360.80. The maximum solubility in water at 25°C is 174 mg/mL. The pkas for valacyclovir hydrochloride are 1.90, 7.47, and 9.43.

What are cold sores, chickenpox, shingles, and genital herpes?

Cold sores are caused by a herpes virus that may be spread by kissing or other physical contact with the infected area of the skin. They are small, painful ulcers that you get in or around your mouth. It is not known if Valtrex can stop the spread of cold sores to others.

Chickenpox is caused by a herpes virus. It causes an itchy rash of multiple small, red bumps that look like pimples or insect bites usually appearing first on the abdomen or back and face. It can spread to almost everywhere else on the body and may be accompanied by flu-like symptoms.

Shingles is caused by the same herpes virus that causes chickenpox. It causes small, painful blisters that happen on your skin. Shingles occurs in people who have already had chickenpox. Shingles can be spread to people who have not had chickenpox or the chickenpox vaccine by contact with the infected areas of the skin. It is not known if Valtrex can stop the spread of shingles to others.

Genital herpes is a sexually transmitted disease. It causes small, painful blisters on your genital area. You can spread genital herpes to others, even when you have no symptoms. If you are sexually active, you can still pass herpes to your partner, even if you are taking Valtrex. Valtrex, taken every day as prescribed and used with the following safer sex practices, can lower the chances of passing genital herpes to your partner.

Do not have sexual contact with your partner when you have any symptom or outbreak of genital herpes.
Use a condom made of latex or polyurethane whenever you have sexual contact.

Ask your healthcare provider for more information about safer sex practices.

Who should not take Valtrex?

Do not take Valtrex if you are allergic to any of its ingredients or to acyclovir. The active ingredient is valacyclovir. See the end of this leaflet for a complete list of ingredients in Valtrex.

What should I tell my healthcare provider before taking Valtrex?

Before taking Valtrex, tell your healthcare provider about all of your medical conditions, including:

if you have had a bone marrow transplant or kidney transplant, or if you have advanced HIV-1 disease or “AIDS”. Patients with these conditions may have a higher chance for getting a blood disorder called thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS). TTP/HUS can result in death.
if you have kidney problems. Patients with kidney problems may have a higher chance for getting side effects or more kidney problems with Valtrex. Your healthcare provider may give you a lower dose of Valtrex.
if you are aged 65 years or older. Elderly patients have a higher chance of certain side effects. Also, elderly patients are more likely to have kidney problems. Your healthcare provider may give you a lower dose of Valtrex.
if you are pregnant or planning to become pregnant. Talk with your healthcare provider about the risks and benefits of taking prescription drugs (including Valtrex) during pregnancy.
if you are breastfeeding. Valtrex may pass into your milk and it may harm your baby. Talk with your healthcare provider about the best way to feed your baby if you are taking Valtrex.
about all the medicines you take, including prescription and non─prescription medicines, vitamins, and herbal supplements. Valtrex may affect other medicines, and other medicines may affect Valtrex. It is a good idea to keep a complete list of all the medicines you take. Show this list to your healthcare provider and pharmacist any time you get a new medicine.

How should I take Valtrex?

Take Valtrex exactly as prescribed by your healthcare provider. Your dose of Valtrex and length of treatment will depend on the type of herpes infection that you have and any other medical problems that you have.

Do not stop Valtrex or change your treatment without talking to your healthcare provider.
Valtrex can be taken with or without food.
If you are taking Valtrex to treat cold sores, chickenpox, shingles, or genital herpes, you should start treatment as soon as possible after your symptoms start. Valtrex may not help you if you start treatment too late.
If you miss a dose of Valtrex, take it as soon as you remember and then take your next dose at its regular time. However, if it is almost time for your next dose, do not take the missed dose. Wait and take the next dose at the regular time.
Do not take more than the prescribed number of Valtrex Caplets each day. Call your healthcare provider right away if you take too much Valtrex.

What are the possible side effects of Valtrex?

Kidney failure and nervous system problems are not common, but can be serious in some patients taking Valtrex. Nervous system problems include aggressive behavior, unsteady movement, shaky movements, confusion, speech problems, hallucinations (seeing or hearing things that are really not there), seizures, and coma. Kidney failure and nervous system problems have happened in patients who already have kidney disease and in elderly patients whose kidneys do not work well due to age. Always tell your healthcare provider if you have kidney problems before taking Valtrex. Call you doctor right away if you get a nervous system problem while you are taking Valtrex.

Common side effects of Valtrex in adults include:

headache
nausea
stomach pain
vomiting
dizziness.

Side effects in HIV-1-infected adults include headache, tiredness, and rash. These side effects usually are mild and do not cause patients to stop taking Valtrex.

Other less common side effects in adults include painful periods in women, joint pain, depression, low blood cell counts, and changes in tests that measure how well the liver and kidneys work.

The most common side effect seen in children aged less than 18 years was headache.

Talk to your healthcare provider if you develop any side effects that concern you.

These are not all the side effects of Valtrex. For more information ask your healthcare provider or pharmacist.

General information about Valtrex

Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not use Valtrex for a condition for which it was not prescribed. Do not give Valtrex to other people, even if they have the same symptoms you have. It may harm them.

This guide summarizes the most important information about Valtrex. If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about Valtrex that is written for health professionals.

How should I store Valtrex?

Store Valtrex Caplets at room temperature, 59° to 77°F (15° to 25°C).
Store Valtrex suspension between 2° to 8°C (36° to 46°F) in a refrigerator. Discard after 28 days.
Keep Valtrex in a tightly closed container.
Do not keep medicine that is out of date or that you no longer need.
Keep Valtrex and all medicines out of the reach of children.

What are the ingredients in Valtrex?

Active Ingredient: valacyclovir hydrochloride

Inactive Ingredients: carnauba wax, colloidal silicon dioxide, crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, and titanium dioxide.