valacyclovir (Rx)

Brand and Other Names:Valtrex
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Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

tablet

  • 500mg
  • 1g

Herpes Labialis

2 g PO q12hr for 1 day

Herpes Zoster

1 g PO q8hr for 7 days (no data on efficacy if started 72 hours after rash)

Genital Herpes

Initial episode: 1 g PO q12hr for 10 days

Recurrent episodes: 500 mg PO q12hr for 3 days (no data on efficacy if started >24 hours after lesion onset)

Suppressive therapy (immunocompetent patients): 1 g/day PO

Suppressive therapy (immunocompetent patients with ≤9 recurrences annually): 500 mg/day PO; transmission reduction for source partner, 500 mg/day PO

Suppressive therapy (HIV-infected patients): 500 mg PO q12hr

Dosing Modifications

Herpes labialis

  • CrCl 30-49 mL/min: 1 g PO q12hr for 1 day
  • CrCl 10-29 mL/min: 500 mg PO q12hr for 1 day
  • CrCl <10 mL/min: 500 mg PO once

Herpes zoster

  • CrCl 30-49 mL/min: 1 g PO q12hr
  • CrCl 10-29 mL/min: 1 g/day PO
  • CrCl <10 mL/min: 500 mg/day PO

Genital herpes (initial episode)

  • CrCl 10-29 mL/min: 1 g/day PO
  • CrCl <10 mL/min: 500 mg/day PO qDay

Genital herpes (recurrent episodes)

  • CrCl ≤29 mL/min: 500 mg/day PO

Genital herpes (suppressive therapy, immunocompetent patients)

  • CrCl ≤29 mL/min: 500 mg/day PO

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

  • CrCl ≤29 mL/min: 500 mg PO q48hr

Genital herpes (suppressive therapy, HIV-infected patients)

  • CrCl ≤29 mL/min: 500 mg/day PO

Dosage Forms & Strengths

tablet

  • 500mg
  • 1g

Chickenpox

<2 years: Safety and efficacy not established

>2 years: 20 mg/kg PO q8hr for 5 days; not to exceed 1 g PO q8hr  

Herpes Labialis

<12 years: Safety and efficacy not established

>12 years: 2 g PO q12hr for 1 day

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

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Interactions

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            Adverse Effects

            >10%

            Headache (14-35%)

            Neutropenia (<18%)

            Elevated aspartate transaminase (AST) (2-16%)

            Nasopharyngitis (<16%)

            Nausea (6-15%)

            Elevated alanine transaminase (ALT) (<14%)

            Abdominal pain (2-11%)

            1-10%

            Dysmenorrhea (1-8%)

            Depression (<7%)

            Arthralgia (<1-6%)

            Vomiting (<1-6%)

            Dizziness (2-4%)

            Rash (≤8%)

            Rhinorrhea (<2%)

            Thrombocytopenia (<3%)

            Leukopenia (≤1%)

            <1%

            Agitation

            Aggression

            Alopecia

            Confusion

            Erythema multiforme

            Hypertension

            Tachycardia

            Tremor

            Visual disturbances

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            Warnings

            Contraindications

            Hypersensitivity to valacyclovir or acyclovir

            Cautions

            Thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) reported in patients with advanced HIV disease and in allogenic bone marrow transplant and renal transplant recipients

            Acute renal failure (ARF) may occur, especially in elderly patients or those with underlying renal impairment receiving higher than recommended doses; use with caution in patients with renal impairment, the elderly, and/or patients receiving nephrotoxic drugs

            Treatment should begin with the earliest symptom (tingling, burning, itching) in cold sores; for genital herpes, it should begin at the first signs and symptoms (within 72 hours of onset of first diagnosis or 24 hours of onset of recurrent episodes); for herpes zoster, it should begin within 72 hours of onset of rash; for chicken pox, it should begin with the earliest sign or symptom

            Central nervous system (CNS) effects may occur (eg, agitation, hallucinations, confusion, encephalopathy); risk of CNS adverse effects is higher in elderly patients

            Adequately hydrate patient; decreased precipitation in renal tubules may occur

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            Pregnancy & Lactation

            Pregnancy

            Clinical data over several decades with valacyclovir and its metabolite, acyclovir, in pregnant women, have not identified a drug associated risk of major birth defects; there are insufficient data on use of valacyclovir regarding miscarriage or adverse maternal or fetal outcomes; there are risks to fetus associated with untreated herpes simplex during pregnancy

            Risk of neonatal HSV infection varies from 30% to 50% for genital HSV acquired in late pregnancy (third trimester), whereas with HSV acquisition in early pregnancy, risk of neonatal infection is about 1%; a primary herpes occurrence during first trimester of pregnancy has been associated with neonatal chorioretinitis, microcephaly, and, in rare cases, skin lesions; in very rare cases, transplacental transmission can occur resulting in congenital infection, including microcephaly, hepatosplenomegaly, intrauterine growth restriction, and stillbirth

            Co-infection with HSV increases risk of perinatal HIV transmission in women who had a clinical diagnosis of genital herpes during pregnancy

            Animal data

            • In animal reproduction studies, no evidence of adverse developmental outcomes was observed with valacyclovir when administered to pregnant rats and rabbits at system exposures (AUC) 4 (rats) and 7 (rabbits) times human exposure at maximum recommended human dose (MRHD)

            Lactation

            Although there is no information on presence of drug in human milk, its metabolite, acyclovir, is present in human milk following oral administration of drug; based on published data, a 500-mg maternal dose twice daily would provide a breastfed child with an oral acyclovir dosage of approximately 0.6 mg/kg/day; there is no data on effects of drug on breastfed child or on milk production

            Consider developmental and health benefits of breastfeeding along with mother’s clinical need for therapy and any potential adverse effects on breastfed child from drug or from underlying maternal condition

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Converted to acyclovir by intestinal and hepatic metabolism

            Competes with deoxyguanosine triphosphate for viral DNA polymerase to inhibit DNA synthesis and viral replication

            Absorption

            Rapidly absorbed

            Bioavailability: ~55% (after conversion to acyclovir)

            Distribution

            Acyclovir (active drug) is widely distributed throughout the body, including brain, kidney, muscle, uterus, lungs, liver, spleen, vagina, and cerebrospoinal fluid (CSF)

            Protein bound: 13.5-17.9%

            Metabolism

            Metabolized by liver; valacyclovir is rapidly and nearly completely converted to acyclovir and L-valine via first-pass effect; acyclovir is hepatically metabolized to a very small extent by aldehyde oxidase and by alcohol and aldehyde dehydrogenase (inactive metabolites)

            Elimination

            Half-life (normal renal function, adults): Acyclovir, 2.5-3.3 hr; valacyclovir, ~30 min

            Half-life (end-stage renal disease): Acyclovir, 14-20 hr

            Excretion: Urine (89%), feces (minimal)

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            Valtrex oral
            -
            500 mg tablet
            Valtrex oral
            -
            1 gram tablet
            valacyclovir oral
            -
            1 gram tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            1 gram tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            1 gram tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            1 gram tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            1 gram tablet
            valacyclovir oral
            -
            500 mg tablet
            valacyclovir oral
            -
            1 gram tablet
            valacyclovir oral
            -
            1 gram tablet

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

            Patient Education
            valacyclovir oral

            VALACYCLOVIR - ORAL

            (val-uh-SYE-klo-veer)

            COMMON BRAND NAME(S): Valtrex

            USES: 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.

            HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start taking valacyclovir and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take valacyclovir by mouth, with or without food, as directed by your doctor. Drink plenty of fluids while taking this medication to lower the chance of side effects.The dosage and length of treatment are based on your type of infection, medical condition, and response to treatment. For treating chickenpox in children, the dosage is also based on weight.This medication works best when started at the first sign of an outbreak, as directed by your doctor. It may not work as well if you delay treatment. For shingles or chickenpox, start taking valacyclovir at the first symptom or as soon as possible after the rash appears. For cold sores or genital herpes, start taking this medication at the first sign or as soon as you feel tingling, itching, or burning.Valacyclovir works best when the amount of medicine in your body is kept at a constant level. Take this drug at evenly spaced intervals. To help you remember, take it at the same time(s) each day.Continue to take this medication until the full prescribed amount is finished. Do not change your dose, skip any doses, or stop this medication early without your doctor's approval.Tell your doctor if your condition lasts or gets worse.

            SIDE EFFECTS: Nausea, stomach pain, headache, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as agitation, confusion, hallucinations), trouble speaking, shaky/unsteady movements, signs of kidney problems (such as change in the amount of urine).This medication may rarely cause a life-threatening disorder that affects the blood cells, kidneys, and other parts of the body. This disorder is more likely to occur if you have conditions related to a weakened immune system (such as HIV disease, bone marrow transplant, kidney transplant). Get medical help right away if you have any serious side effects, including: extreme tiredness, slow/fast/irregular heartbeat, easy bruising/bleeding, new fever, bloody/dark urine, severe stomach/abdominal pain, yellowing eyes/skin, sudden vision changes, loss of consciousness, seizures.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

            PRECAUTIONS: See also Side Effects section.Before taking valacyclovir, tell your doctor or pharmacist if you are allergic to it; or to acyclovir; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems.This drug may rarely make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Do not have certain immunizations/vaccinations (such as vaccines against the varicella virus) without the consent of your doctor.Older adults may be more sensitive to the side effects of this drug, especially mental/mood changes (such as confusion, agitation) and kidney problems (such as a change in the amount of urine).Cold sores can spread easily. Avoid close physical contact with others (such as kissing) during an outbreak until the cold sores have completely healed. Try not to touch the cold sore. If you do, wash your hands afterward.Valacyclovir does not prevent the spread of herpes. To lower the chance of giving genital herpes to your partner, do not have sexual contact during an outbreak or if you have symptoms. You can spread genital herpes even if you do not have symptoms. Always use an effective barrier method (latex or polyurethane condoms/dental dams) during all sexual activity. Consult your doctor or pharmacist for more details.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This medication passes into breast milk, but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: other drugs that may cause kidney problems (including nonsteroidal anti-inflammatory drugs-NSAIDs such as ibuprofen, naproxen).Valacyclovir is very similar to acyclovir. Do not use medications containing acyclovir while using valacyclovir.

            OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: change in the amount of urine, extreme tiredness, mental/mood changes, loss of consciousness, seizures.

            NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.

            MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

            STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

            Information last revised March 2022. Copyright(c) 2022 First Databank, Inc.

            IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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            Formulary

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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.