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Valacyclovir

Medical and Pharmacy Editor:

Brand Name: Valtrex

Generic Name: Valacyclovir

Drug Class: Antivirals

What Is Valacyclovir and How Does It Work?

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.

Valacyclovir may also be used to prevent another type of viral infection (cytomegalovirus) in some people.

Valacyclovir is available under the following different brand names: Valtrex.

Dosages of Valacyclovir :

Adult and Pediatric Dose Forms and Strengths

Capsule

  • 10 mg
  • 20 mg

Herpes Labialis

  • Adult: 2 g orally every 12 hours for 1 day
  • Children under 12 years: Safety and efficacy not established
  • Children over 12 years: 2 g orally every 12 hours for 1 day

Herpes Zoster

  • 1 g orally every 8 hours for 7 days (no data on efficacy if started 72 hours after rash)

Genital Herpes

  • Initial episode: 1 g orally every 12 hours for 10 days
  • Recurrent episodes: 500 mg orally every 12 hours for 3 days (no data on efficacy if started more than 24 hours after lesion onset)
  • Suppressive therapy (immunocompetent patients): 1 g/day orally
  • Suppressive therapy (immunocompetent patients with up to 9 recurrences annually): 500 mg/day orally; transmission reduction for source partner, 500 mg/day orally
  • Suppressive therapy (HIV-infected patients): 500 mg orally every 12 hours

Chickenpox, Pediatric

  • Children under 2 years: Safety and efficacy not established
  • Children over 2 years: 20 mg/kg orally every 8 hours for 5 days; not to exceed 1 g orally every 8 hours

Dosing Modifications

  • Geriatric: Monitor renal function; dosage may have to be adjusted, depending on renal status

Herpes labialis

  • CrCl 30-49 mL/min: 1 g orally every 12 hours for 1 day
  • CrCl 10-29 mL/min: 500 mg orally every 12 hours for 1 day
  • CrCl less than 10 mL/min: 500 mg orally once

Herpes zoster

  • CrCl 30-49 mL/min: 1 g orally every 12 hours
  • CrCl 10-29 mL/min: 1 g/day orally
  • CrCl less than 10 mL/min: 500 mg/day orally

Genital herpes (initial episode)

  • CrCl 10-29 mL/min: 1 g/day orally
  • CrCl less than 10 mL/min: 500 mg/day orally once/day

Genital herpes (recurrent episodes)

  • CrCl up to 29 mL/min: 500 mg/day orally

Genital herpes (suppressive therapy, immunocompetent patients)

  • CrCl up to 29 mL/min: 500 mg/day orally

Genital herpes (suppressive therapy, immunocompetent patients with up to 9 recurrences annually)

  • CrCl up to 29 mL/min: 500 mg orally every 48 hours

Genital herpes (suppressive therapy, HIV-infected patients)

  • CrCl up to 29 mL/min: 500 mg/day orally

What Are Side Effects Associated with Using Valacyclovir ?

Side effects of valacyclovir include:

Less common side effects of valacyclovir include:

  • Aggression
  • Agitation
  • Confusion
  • Erythema multiforme
  • Fast heart rate
  • Hair loss
  • High blood pressure (hypertension)
  • Tremor
  • Visual disturbances
  • This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

    What Other Drugs Interact with Valacyclovir ?

    If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

    Valacyclovir has no known severe interactions with other drugs.

    Serious interactions of valacyclovir include:

    Moderate interactions of valacyclovir include:

    • cimetidine
    • elvitegravir/cobicistat/emtricitabine/tenofovir DF
    • emtricitabine
    • tenofovir DF

    Mild interactions of valacyclovir include:

    This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.

    What Are Warnings and Precautions for Valacyclovir ?

    Warnings

    This medication contains valacyclovir. Do not take Valtrex if you are allergic to valacyclovir or any ingredients contained in this drug.

    Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.

    Contraindications

    • Hypersensitivity to valacyclovir or acyclovir

    Effects of Drug Abuse

    • No information available

    Short-Term Effects

    • See "What Are Side Effects Associated with Using Valacyclovir?"

    Long-Term Effects

    • See "What Are Side Effects Associated with Using Valacyclovir?"

    Cautions

    Pregnancy and Lactation

    • Valacyclovir may be acceptable for use during pregnancy. Either animal studies show no risk but human studies are not available or animal studies showed minor risks and human studies were done and showed no risk.
    • Valacyclovir is excreted in breast milk; use with caution if breastfeeding.
    Reviewed on 5/18/2017

    Medscape. Valacyclovir.
    https://reference.medscape.com/drug/valtrex-valacyclovir-342631
    RxList. Valtrex Side Effects Center.
    https://www.rxlist.com/valtrex-side-effects-drug-center.htm

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