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Valacyclovir

Pronounced

"val-uh-SYE-klo-veer"

Common brand names:

Valtrex

Uses

Valacyclovir is used to treat infections caused by certain types of viruses. In children, it is used to treat cold sores around the mouth (caused by herpes simplex) and chickenpox (caused by varicella zoster). In adults, it is used to treat shingles (caused by herpes zoster) and cold sores around the mouth.

Valacyclovir is also used to treat outbreaks of genital herpes. In people with frequent outbreaks, this medication is used to reduce the number of future episodes.

Valacyclovir is an antiviral drug. It stops the growth of certain viruses. However, it is not a cure for these infections. The viruses that cause these infections continue to live in the body even between outbreaks. Valacyclovir decreases the severity and length of these outbreaks. It helps the sores heal faster, keeps new sores from forming, and decreases pain/itching. This medication may also help reduce how long pain remains after the sores heal.

Other Uses

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used to reduce the risk of another type of viral infection (cytomegalovirus) in some people.

How to Use This Medication

Read the Patient Information Leaflet if available from your pharmacist before you start taking valacyclovir and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take valacyclovir by mouth with or without food as directed by your doctor. Drink plenty of fluids while taking this medication to lower the chance of side effects.

The dosage and length of treatment are based on your medical condition and response to treatment. Children's dosage may also be based on weight.

This medication works best when started at the first sign of an outbreak, as directed by your doctor. It may not work as well if you delay treatment. For shingles or chickenpox, start taking valacyclovir at the first symptom or as soon as possible after the rash appears. For cold sores or genital herpes, start taking this medication at the first sign or as soon as you feel tingling, itching, or burning.

Valacyclovir works best when the amount of medicine in your body is kept at a constant level. Take this drug at evenly spaced intervals. To help you remember, take it at the same time(s) each day.

Continue to take this medication until the full prescribed amount is finished. Do not change your dose, skip any doses, or stop this medication early without your doctor's approval.

Tell your doctor if your condition lasts or gets worse.

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Drug information is selected from data included with permission and copyrighted by First DataBank, Inc. This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your healthcare professional. Always seek the advice of your healthcare professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your healthcare professional. This information does not contain any assurances that this product is safe, effective or appropriate for you.

This information is intended only for residents of the United States. Products sold under the same brand names in other countries may contain different ingredients.

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Information expires December 2025.