What is Valacyclovir Hcl: Uses, Warnings & Interactions

Updated Feb 8, 2024  •  Published Dec 30, 2020

Valacyclovir Hcl overview

BRAND NAMES:

  • Valtrex

Generic Names:

  • Valacyclovir HCI

Uses:

  • Treats herpes virus infections, including shingles, cold sores, chickenpox, and genital herpes.

Therapeutic Classes:

  • Antiviral

Forms:

  • Tablet

How it’s taken:

  • By mouth

What is Valacyclovir Hcl used for?

The FDA has approved valacyclovir to treat herpes infections including genital herpes, cold sores, chickenpox, and shingles. Valacyclovir does not cure herpes. Instead, it’s used to more quickly resolve symptomatic flare-ups or prevent outbreaks when there are no symptoms.

What form(s) does Valacyclovir Hcl come in

  • Tablet

    • 500 mg

    • 1,000 mg

What are common Valacyclovir Hcl doses?

  • For cold sores in adults and adolescents: 2,000 mg taken orally every 12 hours for 1 day

  • For genital herpes in adults: 1,000 mg taken orally every 12 hours for 7–10 days for the initial episode, 500 mg taken orally every 12 hours for 3 days for recurrent episodes, 1,000 mg taken orally once per day to suppress genital herpes

  • For shingles in adults: 1,000 mg taken every 8 hours for 7 days

  • For chickenpox in children 2 years of age and older: 20 mg/kg dose taken by mouth every 8 hours for 5 days

  • Dosages will be different for people with weakened immune systems or who are also infected with HIV. For more details, read more about valayclovir dosages, forms, and strengths page here.

Common Valacyclovir Hcl prescriptions

  • valACYclovir HCl
    1gm tablet

  • valACYclovir HCl
    500mg tablet

How to take Valacyclovir Hcl

  • Your doctor will tell you how much medicine to use. Do not use more than directed.

  • This medicine works best when you take it at the first sign of a herpes breakout.

  • Valtrex tablets can be taken with or without food.

  • Drink extra fluids so you will urinate more often and help prevent kidney problems.

  • A pharmacist can prepare a valacyclovir oral suspension (liquid) for easier dosing. The pharmacist will supply you with dosing and storage instructions. 

  • Store valacyclovir in a closed container at room temperature protected from moisture.

What to do if you miss a dose of Valacyclovir Hcl

  • 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.

Valacyclovir Hcl contraindications

  • This medicine is not right for everyone. 

  • Do not use it if you have had an allergic reaction to valacyclovir or acyclovir.

Valacyclovir Hcl warnings

  • Tell any doctor or other healthcare provider who treats you that you are using this medicine.

  • Tell your doctor if:

    • You have HIV or AIDS

    • You have had a bone marrow or kidney transplant

    • If you are pregnant or breastfeeding

  • This medicine may cause the following problems: 

    • Kidney problems or kidney failure

    • Nervous system problems such as agitation, hallucinations, confusion, and delirium

  • People with an HIV infection or a recent bone marrow or kidney transplant who take valacyclovir could experience a potentially fatal side effect called thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS).

  • Do not have sex while you have herpes sores. Valacyclovir will not stop the spread of herpes during sex.

  • Even if you have no signs of a herpes infection, it is still possible to spread the virus to others. Always use condoms made from latex or polyurethane when you have sexual contact.

  • Call your doctor if your symptoms do not improve or if they get worse.

  • Do not stop using this medicine suddenly, or change how you take it, without talking to your doctor.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Valacyclovir Hcl interactions

  • To avoid potentially hazardous drug interactions, tell the prescribing healthcare provider about all prescription drugs, over-the-counter medicines, and supplements you are using before taking valacyclovir.

  • Tell other healthcare providers you are using this medicine before they prescribe new medications.

Valacyclovir Hcl side effects

Serious side effects

Talk to a doctor if you notice any signs or symptoms of a possible serious side effect including:

  • Symptoms of TTP/HUS: 

    • Pinpoint red spots on your skin, unusual bleeding or bruising, blood in your urine or stools

    • Headache, confusion, fever

    • Fast heartbeat, fainting, or extreme weakness

    • Pale or yellow skin 

  • Decrease in how much or how often you urinate

  • Problems with walking, speaking, or coordination, seeing or hearing things that are not there

  • Seizures or tremors

  • Confusion, agitation, depression, hallucinations, delirium, or similar mental changes

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

Less serious side effects

  • Headache

  • Nausea

  • Stomach pain

Sources: