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Valacyclovir (By mouth)

Valacyclovir (val-ay-SYE-kloe-vir)

Treats herpes virus infections, including shingles (herpes zoster), cold sores (herpes labialis), and genital herpes (herpes simplex) in adults. Also treats cold sores and chicken pox in children. This medicine will not cure herpes, but may prevent a breakout of herpes sores or blisters.

Brand Name(s):

Valtrex

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You or your child should not use this medicine if you have had an allergic reaction to valacyclovir or acyclovir (Zovirax®).

How to Use This Medicine:

Tablet

  • Take your medicine as directed.
  • You may take this medicine with or without food.
  • Take this medicine at the first sign of a herpes breakout or as soon as possible. The medicine might not work as well if you start using it too late.
  • Drink extra fluids so you will urinate more often and help prevent kidney problems.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you or your child are using medicines that weaken your immune system, such as a steroid or cancer medicine. Some examples of steroids are dexamethasone, prednisolone, prednisone, and Medrol®.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you or your child are pregnant or breastfeeding, or if you have kidney disease or a weak immune system. Some things that cause a weak immune system are cancer medicines, HIV/AIDS, a recent infection, or a recent bone marrow or kidney transplant.
  • Valacyclovir will not stop the spread of herpes during sex. Avoid having sex while you have herpes sores.
  • Even if you have no signs of a herpes infection, it is still possible to spread the virus to others during sex. Talk with your doctor about ways to keep from spreading the virus.
  • Call your doctor if your symptoms do not improve or if they get worse.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
  • Do not stop using this medicine suddenly, or change how you take it, without talking to your doctor.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blood in your urine or stools.
  • Confusion, agitation, depression, or other behavior changes.
  • Decrease in how much or how often you urinate.
  • Dry mouth, increased thirst, or muscle cramps.
  • Fainting or extreme weakness.
  • Fast heartbeat.
  • Fever, chills, cough, sore throat, runny or stuffy nose, and body aches.
  • Pinpoint red spots on your skin.
  • Problems with walking, speaking, or coordination.
  • Seeing, hearing, or feeling things that are not really there.
  • Seizures (convulsions) or tremors.
  • Unusual bleeding or bruising.
  • Yellowing of your skin or the whites of your eyes.

If you notice these less serious side effects, talk with your doctor:

  • Headache or dizziness.
  • Joint pain.
  • Menstrual cramps.
  • Nausea, vomiting, diarrhea, or stomach pain.
  • Problems with vision.
  • Skin rash.
  • Tiredness.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 4/4/2014

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