Valtrex Uses, Side Effects and Dosage

Valtrex Uses, SIde Effects and Dosage

What is Valtrex (Valacyclovir)?

Valtrex  and Zelitrex are the brand names of an oral medication in the antiviral drug class. Their generic counterpart is valcivir. Each Valtrex caplet’s active ingredient is valacyclovir. The drug is primarily used to treat various strains of herpes, including cold sores (herpes labialis).  Valtrex is manufactured by GlaxoSmithKline.

What is this medication used for?

Valtrex is not only used to treat cold sores, but genital herpes. It treats initial and recurrent herpes episodes in immunocompetent adults, and it is also used as part of chronic suppressive therapy in HIV-infected adults. Its primary goal is to help supress and reduce the transmission of genital herpes beyond a year in immunocompetent adults and for 6 months in HIV-1-infected patients. Valacyclovir is also used to treat herpes zoster (shingles) chickenpox in children aged 2 and above.

How to take Valacyclovir

Valacyclovir is available in both caplet and oral suspension liquid form. The medication can be taken with or without food. Its dosage amounts change depending on what it condition it is being used to treat. Valtrex is a treatment and not a cure for genital herpes. All dosages should be given at the first sign of infection.


  • Adult cold sores: 2 grams twice daily at 12-hour intervals
  • Initial episode: 1 gram twice daily for 10 days
  • Recurrent episodes: 500 mg twice daily for 10 days
  • Suppressive therapy: 1 gram once a day for patients with normal immune systems, or 500mg twice daily for patients with HIV-1 that have a CD4+ cell count that is equal to or greater than 100 cells/
  • Transmission reduction: 500 mg once a day for the credit partner in patients with 9 or less recurrences per year
  • Pediatric cold sores: 2 grams twice daily with meals for kids over 1 month old and based on body surface.
  • Chicken pox: (ages 2-17) 20mg/kg 3 times a day for 5 days. Cannot give more than 1 gram 3 times a day.
  • Valtrex oral suspension: 500 mg caplets, or 25mg/mL prepared in lots of 100mL.

Warnings and Precautions

Patients taking Zelitrex may experience the following:

  • Potentially fatal Thrombotic Thrombocytopenic Purpura/Hemolytic Uremic Syndrome (TTP/HUS), particularly in patients with HIV-1, as well as patients that have had bone marrow and renal transplants.
  • Acute renal failure in elderly patients, patients with renal disease, those receiving nephrotoxic drugs, and dehydrated patients.
  • Adverse central nervous system reactions in patients with renal disease. Elderly patients are more likely to suffer from these reactions than adults or children.

Valacyclovir is contraindicated in the following:

  • Pregnant and nursing women
  • Elderly patients
  • Patients with renal impairment
  • Patients with hypersensitivity to or allergic reactions to valacyclovir or any of its ingredients

Valtrex side effects

Common side effects

  • Nauseae
  • Vomiting
  • Stomach pain
  • Dizziness
  • Tiredness
  • Rash
  • Headache

Serious side effects

  • Irregular menstrual bleeding
  • Joint pain
  • Depression
  • Low blood cell counts
  • Changes in test given to measure liver or kidney function
  • Signs of overactive thyroid such as: irritability, trouble breathing, cough, skin sores that don’t heal

See your doctor immediately if you experience the following:

  • Nervous system problems

For more information on adverse reactions, warnings and contraindications, please refer to the package insert.

Disclaimer: Please note that the contents of this article are for informational purposes only and should not be considered medical advice. This article, and other AIDS and HIV Information articles on AIDS Drugs Online, are not written by AIDS Drugs Online or reviewed by its staff for medical validity. All views and opinions expressed by the third-party authors are not endorsed by AIDS Drugs Online or its staff. Always consult a medical professional for medical advice.


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