What is valacyclovir?

Valacyclovir is an antiviral drug. It slows the growth and spread of the herpes virus so that the body can fight off the infection. Valacyclovir will not cure herpes, but it can lessen the symptoms of the infection.

Valacyclovir is used to treat infections caused by herpes viruses in adults and children. Illnesses caused by herpes viruses include genital herpes, cold sores, shingles, and chickenpox.

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

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

Precautions

Do not take this medicine if you are allergic to valacyclovir or acyclovir (Zovirax).

If you have certain conditions, you may need a dose adjustment or special tests to safely take this medication. Before taking valacyclovir, tell your doctor if you have:

  • HIV/AIDS, or other conditions that can weaken the immune system;
  • kidney disease (or if you are on dialysis); or
  • if you have had a kidney or bone marrow transplant.

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. However, herpes virus can be passed from an infected mother to her baby during childbirth. If you have genital herpes, it is very important to prevent herpes lesions during your pregnancy so that you do not have a genital lesion when your baby is born.

Valacyclovir passes into breast milk and may harm a nursing infant. Do not take this medication without telling your doctor if you are breast-feeding a baby.

Do not give valacyclovir to a child unless it has been prescribed by a doctor.

Older adults may be more likely to have harmful side effects while taking valacyclovir. Talk to your doctor about your specific risk.

Valacyclovir will not prevent the spread of genital herpes. Herpes infections are contagious and you can infect other people even while you are taking with valacyclovir.

Avoid sexual intercourse or use a latex condom to prevent spreading the virus to others. Avoid letting infected areas come into contact with other people. Avoid touching an infected area and then touching your eyes. Wash your hands frequently to prevent passing the infection to others.

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Instructions

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include urinating less than usual or not at all.

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

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Side Effects

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

Stop taking valacyclovir and call your doctor right away if you have any of the following signs of a serious side effect that can harm red blood cells:

  • fever, easy bruising or bleeding;
  • red spots on the skin (not related to herpes or chickenpox);
  • bloody diarrhea, vomiting;
  • pale or yellowed skin;
  • weakness or fainting; or
  • urinating less than usual or not at all.

Call your doctor at once if you have any of these other serious side effects:

  • pain in your lower back;
  • drowsiness, mood changes, increased thirst, loss of appetite, nausea and vomiting;
  • swelling, weight gain, feeling short of breath;
  • confusion, agitation, aggression, hallucinations, trouble concentrating;
  • feeling shaky or unsteady;
  • problems with speech or vision; or
  • seizure (convulsions).

Less serious side effects may include:

  • nausea, stomach pain;
  • headache, dizziness, tired feeling, depression;
  • joint pain;
  • menstrual pain;
  • mild skin rash; or
  • stuffy nose, sore throat.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

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Interactions

Valacyclovir can be harmful to the kidneys, and these effects are increased when it is used together with other medicines that can harm the kidneys. Before taking valacyclovir, tell your doctor if you are also using:

  • lithium (Eskalith, Lithobid);
  • methotrexate (Rheumatrex, Trexal);
  • pain or arthritis medicines such as aspirin (Anacin, Excedrin), acetaminophen (Tylenol), diclofenac (Voltaren), etodolac (Lodine), ibuprofen (Advil, Motrin), indomethacin (Indocin), naproxen (Aleve, Naprosyn), and others;
  • medicines used to treat ulcerative colitis, such as mesalamine (Pentasa) or sulfasalazine (Azulfidine);
  • medicines used to prevent organ transplant rejection, such as sirolimus (Rapamune) or tacrolimus (Prograf);
  • IV antibiotics such as amphotericin B (Fungizone, AmBisome, Amphotec, Abelcet), amikacin (Amikin), bacitracin (Baci-IM), capreomycin (Capastat), gentamicin (Garamycin), kanamycin (Kantrex), streptomycin, or vancomycin (Vancocin, Vancoled);
  • antiviral medicines such as adefovir (Hepsera), cidofovir (Vistide), or foscarnet (Foscavir); or
  • cancer medicine such as aldesleukin (Proleukin), carmustine (BiCNU, Gliadel), cisplatin (Platinol), ifosfamide (Ifex), oxaliplatin (Eloxatin), plicamycin (Mithracin), streptozocin (Zanosar), or tretinoin (Vesanoid).

This list is not complete and there may be other drugs that can interact with valacyclovir. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

Other Names

Valtrex and valacyclovir

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Disclaimer

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2004 Cerner Multum, Inc. Version 2.05. Revision date 8/23/04

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