Valtrex (valacyclovir) is an antiviral drug. It slows the growth and spread of the herpes virus to help the body fight the infection.

Valtrex is used to treat infections caused by herpes viruses, including genital herpes, cold sores, and shingles (herpes zoster) in adults.

Valtrex is used to treat cold sores in children who are at least 12 years old, or chickenpox in children who are at least 2 years old.

Valtrex will not cure herpes and will not prevent you from spreading the virus to other people. However, this medicine can lessen the symptoms of an infection.

Valtrex may also be used for purposes not listed in this medication guide.

Take Valtrex exactly as it was prescribed for you. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Start taking Valtrex as soon as possible after the first appearance of symptoms (such as tingling, burning, blisters). This medicine might not be as effective if you first start taking it 1 or 2 days after the start of your symptoms.

Some herpes infections need to be treated for longer than others. Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may increase the risk of your virus becoming resistant to antiviral medicine.

You may take Valtrex with or without food.

Drink plenty of water while you are taking Valtrex to keep your kidneys working properly.

If you or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.

The areas affected by genital herpes, chickenpox, or shingles should be kept as clean and dry as possible. Also, wear loose-fitting clothing to avoid irritating the sores (blisters).

It is important to remember that this medicine will not keep you from spreading herpes to others.

Herpes infection of the genitals can be caught from or spread to your partner during any sexual activity. Even though you may get herpes if your partner has no symptoms, the infection is more likely to be spread if sores are present. This is true until the sores are completely healed and the scabs have fallen off. Therefore, it is best to avoid any sexual activity if either you or your sexual partner has any symptoms of herpes. The use of a latex condom (“rubber") may help prevent the spread of herpes. However, spermicidal (sperm-killing) jelly or a diaphragm will probably not help.

Get emergency medical help if you have signs of an allergic reaction to Valtrex: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

Confusion, aggression, or you feel shaky or unsteady;

Hallucinations (seeing or hearing things that are not real);

Problems with speech;

A seizure (convulsions); or

Kidney problems--little or no urination, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath.

What is this medicine?

Valtrex (Valacyclovir) is an antiviral medicine. It is used to treat or prevent infections caused by certain kinds of viruses. Examples of these infections include herpes and shingles. This medicine will not cure herpes.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature between 15 and 25 degrees C (59 and 77 degrees F). Keep container tightly closed. Throw away any unused medicine after the expiration date .