VALTREX®
(valacyclovir hydrochloride)
Caplets

VALTREX (valacyclovir hydrochloride) is the hydrochloride salt of L-valyl ester of the antiviral drug acyclovir (ZOVIRAX^® Brand, GlaxoSmithKline).

VALTREX Caplets are for oral administration. Each caplet contains valacyclovir hydrochloride equivalent to 500 mg or 1 gram valacyclovir and the inactive ingredients carnauba wax, colloidal silicon dioxide, crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, and titanium dioxide. The blue, film-coated caplets are printed with edible white ink.

The chemical name of valacyclovir hydrochloride is L-valine, 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy]ethyl ester, monohydrochloride. It has the following structural formula:

Valacyclovir hydrochloride is a white to off-white powder with the molecular formula C₁₃H₂₀N₆O₄•HCl and a molecular weight of 360.80. The maximum solubility in water at 25°C is 174 mg/mL. The pk_a’s for valacyclovir hydrochloride are 1.90, 7.47, and 9.43.

Valacyclovir hydrochloride is rapidly converted to acyclovir which has demonstrated antiviral activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) and varicella-zoster virus (VZV) both in vitro and in vivo.

The inhibitory activity of acyclovir is highly selective due to its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV. This viral enzyme converts acyclovir into acyclovir monophosphate,a nucleotide analogue. The monophosphate is further converted into diphosphate by cellular guanylate kinase and into triphosphate by a number of cellular enzymes. In vitro, acyclovir triphosphate stops replication of herpes viral DNA. This is accomplished in 3 ways: 1) competitive inhibition of viral DNA polymerase, 2) incorporation and termination of the growing viral DNA chain, and 3) inactivation of the viral DNA polymerase. The greater antiviral activity of acyclovir against HSV compared to VZV is due to its more efficient phosphorylation by the viral TK.

The quantitative relationship between the in vitro susceptibility of herpesviruses to antivirals and the clinical response to therapy has not been established in humans, and virus sensitivity testing has not been standardized. Sensitivity testing results, expressed as the concentration of drug required to inhibit by 50% the growth of virus in cell culture (IC₅₀), vary greatly depending upon a number of factors. Using plaque-reduction assays, the IC₅₀ against herpes simplex virus isolates ranges from 0.02 to 13.5 mcg/mL for HSV-1 and from 0.01 to 9.9 mcg/mL for HSV-2. The IC₅₀ for acyclovir against most laboratory strains and clinical isolates of VZV ranges from 0.12 to 10.8 mcg/mL. Acyclovir also demonstrates activity against the Oka vaccine strain of VZV with a mean IC₅₀ of 1.35 mcg/mL.

Resistance of HSV and VZV to acyclovir can result from qualitative and quantitative changes in the viral TK and/or DNA polymerase. Clinical isolates of VZV with reduced susceptibility to acyclovir have been recovered from patients with AIDS. In these cases, TK-deficient mutants of VZV have been recovered.

Resistance of HSV and VZV to acyclovir occurs by the same mechanisms. While most of the acyclovir-resistant mutants isolated thus far from immunocompromised patients have been found to be TK-deficient mutants, other mutants involving the viral TK gene (TK partial and TK altered) and DNA polymerase have also been isolated. TK-negative mutants may cause severe disease in immunocompromised patients. The possibility of viral resistance to valacyclovir (and therefore, to acyclovir) should be considered in patients who show poor clinical response during therapy.

After oral administration, valacyclovir hydrochloride is rapidly absorbed from the gastrointestinal tract and nearly completely converted to acyclovir and L-valine by first-pass intestinal and/or hepatic metabolism.

The pharmacokinetics of valacyclovir and acyclovir after oral administration of VALTREX have been investigated in 14 volunteer studies involving 283 adults.

Two randomized double-blind clinical trials in immunocompetent adults with localized herpes zoster were conducted. VALTREX was compared to placebo in patients less than 50 years of age, and to ZOVIRAX in patients greater than 50 years of age. All patients were treated within 72 hours of appearance of zoster rash. In patients less than 50 years of age, the median time to cessation of new lesion formation was 2 days for those treated with VALTREX compared to 3 days for those treated with placebo. In patients greater than 50 years of age, the median time to cessation of new lesions was 3 days in patients treated with either VALTREX or ZOVIRAX. In patients less than 50 years of age, no difference was found with respect to the duration of pain after healing (post-herpetic neuralgia) between the recipients of VALTREX and placebo. In patients greater than 50 years of age, among the 83% who reported pain after healing (post-herpetic neuralgia), the median duration of pain after healing [95% confidence interval] in days was: 40 [31, 51], 43 [36, 55], and 59 [41, 77] for 7-day VALTREX, 14-day VALTREX, and 7-day ZOVIRAX, respectively.

Two double-blind, placebo-controlled clinical trials were conducted in 1,856 healthy adults and adolescents (≥12 years old) with a history of recurrent cold sores. Patients self-initiated therapy at the earliest symptoms and prior to any signs of a cold sore. The majority of patients initiated treatment within 2 hours of onset of symptoms. Patients were randomized to VALTREX 2 grams twice daily on Day 1 followed by placebo on Day 2, VALTREX 2 grams twice daily on Day 1 followed by 1 gram twice daily on Day 2, or placebo on Days 1 and 2.

The mean duration of cold sore episodes was about 1 day shorter in treated subjects as compared to placebo. The 2-day regimen did not offer additional benefit over the 1-day regimen.

No significant difference was observed between subjects receiving VALTREX or placebo in the prevention of progression of cold sore lesions beyond the papular stage.

VALTREX is indicated for the treatment of herpes zoster (shingles).

VALTREX is indicated for the treatment or suppression of genital herpes in immunocompetent individuals and for the suppression of recurrent genital herpes in HIV-infected individuals.

When VALTREX is used as suppressive therapy in immunocompetent individuals with genital herpes, the risk of heterosexual transmission to susceptible partners is reduced. Safer sex practices should be used with suppressive therapy (see current Centers for Disease Control and Prevention (CDC) Sexually Transmitted Diseases Treatment Guidelines).

VALTREX is indicated for the treatment of cold sores (herpes labialis).

VALTREX is contraindicated in patients with a known hypersensitivity or intolerance to valacyclovir, acyclovir, or any component of the formulation.

Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), in some cases resulting in death, has occurred in patients with advanced HIV disease and also in allogeneic bone marrow transplant and renal transplant recipients participating in clinical trials of VALTREX at doses of 8 grams per day.

Dosage reduction is recommended when administering VALTREX to patients with renal impairment (see DOSAGE AND ADMINISTRATION). Acute renal failure and central nervous system symptoms have been reported in patients with underlying renal disease who have received inappropriately high doses of VALTREX for their level of renal function. Similar caution should be exercised when administering VALTREX to geriatric patients (see Geriatric Use) and patients receiving potentially nephrotoxic agents.

Given the dosage recommendations for treatment of cold sores, special attention should be paid when prescribing VALTREX for cold sores in patients who are elderly or who have impaired renal function (see DOSAGE AND ADMINISTRATION and Geriatric Use). Treatment should not exceed 1 day (2 doses of 2 grams in 24 hours). Therapy beyond 1 day does not provide additional clinical benefit.

Precipitation of acyclovir in renal tubules may occur when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid. Adequate hydration should be maintained. In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored (see DOSAGE AND ADMINISTRATION).

The safety and efficacy of VALTREX have not been established in immunocompromised patients other than for the suppression of genital herpes in HIV-infected patients. The safety and efficacy of VALTREX for suppression of recurrent genital herpes in patients with advanced HIV disease (CD4 cell count <100 cells/mm³) have not been established. The efficacy of VALTREX for the treatment of genital herpes in HIV-infected patients has not been established. The safety and efficacy of VALTREX have not been established for the treatment of disseminated herpes zoster.

The efficacy of VALTREX for reducing transmission of genital herpes has not been established in individuals with multiple partners and non-heterosexual couples.

Patients should be advised to maintain adequate hydration.

See CLINICAL PHARMACOLOGY: Pharmacokinetics.

The data presented below include references to the steady-state acyclovir AUC observed in humans treated with 1 gram VALTREX given orally 3 times a day to treat herpes zoster. Plasma drug concentrations in animal studies are expressed as multiples of human exposure to acyclovir (see CLINICAL PHARMACOLOGY: Pharmacokinetics).

Valacyclovir was noncarcinogenic in lifetime carcinogenicity bioassays at single daily doses (gavage) of valacyclovir giving plasma acyclovir concentrations equivalent to human levels in the mouse bioassay and 1.4 to 2.3 times human levels in the rat bioassay. There was no significant difference in the incidence of tumors between treated and control animals, nor did valacyclovir shorten the latency of tumors.

Valacyclovir was tested in 5 genetic toxicity assays. An Ames assay was negative in the absence or presence of metabolic activation. Also negative were an in vitro cytogenetic study with human lymphocytes and a rat cytogenetic study.

In the mouse lymphoma assay, valacyclovir was not mutagenic in the absence of metabolic activation. In the presence of metabolic activation (76% to 88% conversion to acyclovir), valacyclovir was mutagenic.

Valacyclovir was mutagenic in a mouse micronucleus assay.

Valacyclovir did not impair fertility or reproduction in rats at 6 times human plasma levels.

Following oral administration of a 500-mg dose of VALTREX to 5 nursing mothers, peak acyclovir concentrations (C_max) in breast milk ranged from 0.5 to 2.3 times (median 1.4) the corresponding maternal acyclovir serum concentrations. The acyclovir breast milk AUC ranged from 1.4 to 2.6 times (median 2.2) maternal serum AUC. A 500-mg maternal dosage of VALTREX twice daily would provide a nursing infant with an oral acyclovir dosage of approximately 0.6 mg/kg/day. This would result in less than 2% of the exposure obtained after administration of a standard neonatal dose of 30 mg/kg/day of intravenous acyclovir to the nursing infant. Unchanged valacyclovir was not detected in maternal serum, breast milk, or infant urine. VALTREX should be administered to a nursing mother with caution and only when indicated.

Safety and effectiveness of VALTREX in pre-pubertal pediatric patients have not been established.

Of the total number of subjects in clinical studies of VALTREX, 906 were 65 and over, and 352 were 75 and over. In a clinical study of herpes zoster, the duration of pain after healing (post-herpetic neuralgia) was longer in patients 65 and older compared with younger adults. Elderly patients are more likely to have reduced renal function and require dose reduction. Elderly patients are also more likely to have renal or CNS adverse events. With respect to CNS adverse events observed during clinical practice, agitation, hallucinations, confusion, delirium, and encephalopathy were reported more frequently in elderly patients (see CLINICAL PHARMACOLOGY, ADVERSE REACTIONS: Observed During Clinical Practice, and DOSAGE AND ADMINISTRATION).

Frequently reported adverse events in clinical trials of VALTREX in healthy patients are uled in Tables 4 and 5.

Laboratory abnormalities reported in clinical trials of VALTREX in otherwise healthy patientsare uled in Table 6.

*Data were not collected prospectively.

LLN = Lower limit of normal.

ULN = Upper limit of normal.

In HIV-infected patients, frequently reported adverse events for VALTREX (500 mg twice daily; n = 194, median days on therapy = 172) and placebo (n = 99, median days on therapy = 59), respectively, included headache (13% vs. 8%), fatigue (8% vs. 5%), and rash (8% vs. 1%). Post-randomization laboratory abnormalities that were reported more frequently in valacyclovir subjects versus placebo included elevated alkaline phosphatase (4% vs. 2%), elevated ALT (14% vs. 10%), elevated AST (16% vs. 11%), decreased neutrophil counts (18% vs. 10%), and decreased platelet counts (3% vs. 0%).

In a clinical study for the reduction of transmission of genital herpes, the adverse events reported by patients receiving VALTREX 500 mg once daily (n = 743) or placebo once daily (n = 741) included headache (VALTREX 29%, placebo 26%), nasopharyngitis (VALTREX 16%, placebo 15%), and upper respiratory tract infection (VALTREX 9%, placebo 10%). In this 8-month study, there were no clinically significant changes from baseline laboratory parameters in subjects receiving VALTREX compared with placebo.

In clinical studies for the treatment of cold sores, the adverse events reported by patients receiving VALTREX (n = 609) or placebo (n = 609) included headache (VALTREX 14%, placebo 10%) and dizziness (VALTREX 2%, placebo 1%). The frequencies of abnormal ALT (>2 x ULN) were 1.8% for patients receiving VALTREX compared with 0.8% for placebo. Other laboratory abnormalities (hemoglobin, white blood cells, alkaline phosphatase, and serum creatinine) occurred with similar frequencies in the 2 groups.

The following events have been identified during post-approval use of VALTREX in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to either their seriousness, frequency of reporting, causal connection to VALTREX, or a combination of these factors.

Renal failure and CNS symptoms have been reported in patients with renal impairment who received VALTREX or acyclovir at greater than the recommended dose. Dose reduction is recommended in this patient population (see DOSAGE AND ADMINISTRATION).

Caution should be exercised to prevent inadvertent overdose (see PRECAUTIONS). Precipitation of acyclovir in renal tubules may occur when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid. In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored (see DOSAGE AND ADMINISTRATION).

VALTREX Caplets may be given without regard to meals.

The recommended dosage of VALTREX for the treatment of herpes zoster is 1 gram orally 3 times daily for 7 days. Therapy should be initiated at the earliest sign or symptom of herpes zoster and is most effective when started within 48 hours of the onset of zoster rash. No data are available on efficacy of treatment started greater than 72 hours after rash onset.

The recommended dosage of VALTREX for the treatment of cold sores is 2 grams twice daily for 1 day taken about 12 hours apart. Therapy should be initiated at the earliest symptom of a cold sore (e.g., tingling, itching, or burning). There are no data on the effectiveness of treatment initiated after the development of clinical signs of a cold sore (e.g., papule, vesicle, or ulcer).

In patients with reduced renal function, reduction in dosage is recommended (see Table 7).

During hemodialysis, the half-life of acyclovir after administration of VALTREX is approximately 4 hours. About one third of acyclovir in the body is removed by dialysis during a 4-hour hemodialysis session. Patients requiring hemodialysis should receive the recommended dose of VALTREX after hemodialysis.

There is no information specific to administration of VALTREX in patients receiving peritoneal dialysis. The effect of chronic ambulatory peritoneal dialysis (CAPD) and continuous arteriovenous hemofiltration/dialysis (CAVHD) on acyclovir pharmacokinetics has been studied. The removal of acyclovir after CAPD and CAVHD is less pronounced than with hemodialysis, and the pharmacokinetic parameters closely resemble those observed in patients with ESRD not receiving hemodialysis. Therefore, supplemental doses of VALTREX should not be required following CAPD or CAVHD.

VALTREX Caplets (blue, film-coated, capsule-shaped tablets) containing valacyclovir hydrochloride equivalent to 500 mg valacyclovir and printed with “VALTREX 500 mg.”

Bottle of 30 (NDC 0173-0933-08).

Bottle of 90 (NDC 0173-0933-010).

Unit dose pack of 100 (NDC 0173-0933-56).

VALTREX Caplets (blue, film-coated, capsule-shaped tablets, with a partial scorebar on both sides) containing valacyclovir hydrochloride equivalent to 1 gram valacyclovir and printed with “VALTREX 1 gram.”

Bottle of 30 (NDC 0173-0565-04).

Bottle of 90 (NDC 0173-0565-10).

Store at 15° to 25°C (59° to 77°F). Dispense in a well-closed container as defined in the USP.

Distributed by

GlaxoSmithKline

Research Triangle Park, NC 27709

Manufactured by:

GlaxoSmithKline

Research Triangle Park, NC 27709

or

DSM Pharmaceuticals, Inc.

Greenville, NC 27834

©2006, GlaxoSmithKline. All rights reserved.

PHARMACIST DETACH HERE AND GIVE INSTRUCTIONS TO PATIENT

VALTREX^® (VAL-trex)

(valacyclovir hydrochloride) Caplets

Read the Patient Information that comes with VALTREX before you start using it and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or treatment. Ask your healthcare provider or pharmacist if you have questions.

What is VALTREX?

VALTREX is a prescription antiviral medicine. VALTREX lowers the ability of herpes viruses to multiply in your body.

VALTREX is used:

• to treat cold sores (also called fever bulers or herpes labialis) in adults
• to treat shingles (also called herpes zoster) in adults
• to treat or control genital herpes outbreaks in adults with normal immune systems
• to control genital herpes outbreaks in adults infected with the human immunodeficiency virus (HIV) with CD4 cell count greater than 100 cells/mm³
• with safer sex practices to lower the chances of spreading genital herpes to others. Even with safer sex practices, it is still possible to spread genital herpes.

VALTREX used daily with the following safer sex practices can lower the chances of passing genital herpes to your partner.

• Do not have sexual contact with your partner when you have any symptom or outbreak of genital herpes.
• Use a condom made of latex or polyurethane whenever you have sexual contact.

VALTREX does not cure herpes infections (cold sores, shingles, or genital herpes).

VALTREX has not been studied in children who have not reached puberty.

What are cold sores, shingles, and genital herpes?

Cold sores are caused by a herpes virus that may be spread by kissing or other physical contact with the infected area of the skin. They are small, painful ulcers that you get in or around your mouth. It is not known if VALTREX can stop the spread of cold sores to others.

Shingles is caused by the same herpes virus that causes chickenpox. It causes small, painful bulers that happen on a certain area of your skin. Shingles occurs in people who have already had chickenpox. Shingles can be spread to people who have not had chickenpox or the chickenpox vaccine by contact with the infected areas of the skin. It is not known if VALTREX can stop the spread of shingles to others.

Genital herpes is a sexually transmitted disease. It causes small, painful bulers on your genital area. You can spread genital herpes to others, even when you have no symptoms. If you are sexually active, you can still pass herpes to your partner, even if you are taking VALTREX. VALTREX, taken every day as prescribed and used with the following safer sex practices, can lower the chances of passing genital herpes to your partner.

• Do not have sexual contact with your partner when you have any symptom or outbreak of genital herpes.
• Use a condom made of latex or polyurethane whenever you have sexual contact.

Ask your healthcare provider for more information about safer sex practices.

Who should not take VALTREX?

Do not take VALTREX if you are allergic to any of its ingredients or to acyclovir. The active ingredient is valacyclovir. See the end of this leaflet for a complete ul of ingredients in VALTREX.

Before taking VALTREX, tell your healthcare provider:

About all your medical conditions, including:

• if you have had a bone marrow transplant or kidney transplant, or if you have advanced HIV disease or "AIDS". Patients with these conditions may have a higher chance for getting a blood disorder called thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS). TTP/HUS can result in death.
• if you have kidney problems. Patients with kidney problems may have a higher chance for getting side effects or more kidney problems with VALTREX. Your healthcare provider may give you a lower dose of VALTREX.
• if you are 65 years of age or older. Elderly patients have a higher chance of certain side effects. Also, elderly patients are more likely to have kidney problems. Your healthcare provider may give you a lower dose of VALTREX.
• if you are pregnant or planning to become pregnant. Talk with your healthcare provider about the risks and benefits of taking prescription drugs (including VALTREX) during pregnancy.
• if you are breastfeeding. VALTREX may pass into your milk and it may harm your baby. Talk with your healthcare provider about the best way to feed your baby if you are taking VALTREX.
• about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. VALTREX may affect other medicines, and other medicines may affect VALTREX. This may happen if you have certain medical conditions such as kidney problems. It is a good idea to keep a complete ul of all the medicines you take. Show this ul to your healthcare provider and pharmacist any time you get a new medicine.

How should I take VALTREX?

Take VALTREX exactly as prescribed by your healthcare provider. Your dose of VALTREX and length of treatment will depend on the type of herpes infection that you have and any other medical problems that you have.

• Do not stop VALTREX or change your treatment without talking to your healthcare provider.
• VALTREX can be taken with or without food.
• If you are taking VALTREX to treat cold sores, shingles, or genital herpes, you should start treatment as soon as possible after your symptoms start. VALTREX may not help you if you start treatment too late.
• If you miss a dose of VALTREX, take it as soon as you remember and then take your next dose at its regular time. However, if it is almost time for your next dose, do not take the missed dose. Wait and take the next dose at the regular time.
• Do not take more than the prescribed number of VALTREX Caplets each day. Call your healthcare provider right away if you take too much VALTREX.

What are the possible side effects of VALTREX?

Kidney failure and nervous system problems are not common, but can be serious in some patients taking VALTREX. Nervous system problemsincludeaggressive behavior, unsteady movement, shaky movements, confusion, speech problems, hallucinations (seeing or hearing things that are really not there), seizures, and coma. Kidney failure and nervous system problems have happened in patients who already have kidney disease and in elderly patients whose kidneys do not work well due to age. Always tell your healthcare provider if you have kidney problems before taking VALTREX. Call your doctor right away if you get a nervous system problem while you are taking VALTREX.

Common side effects of VALTREX include headache, nausea, stomach pain, vomiting, and dizziness. Side effects in HIV-infected adults include headache, tiredness, and rash. These side effects are usually mild and usually do not cause patients to stop taking VALTREX.

Other less common side effects include painful periods in women, joint pain, depression, low blood cell counts, and changes in tests that measure how well the liver and kidneys work.

Talk to your healthcare provider if you develop any side effects that concern you.

These are not all the side effects of VALTREX. For more information ask your healthcare provider or pharmacist.

How should I store VALTREX?

• Store VALTREX at room temperature, 59° to 77°F (15° to 25°C).
• Keep VALTREX in a tightly closed container.
• Do not keep medicine that is out of date or that you no longer need.
• Keep VALTREX and all medicines out of the reach of children.

General information about VALTREX

Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not use VALTREX for a condition for which it was not prescribed. Do not give VALTREX to other people, even if they have the same symptoms you have. It may harm them.

This leaflet summarizes the most important information about VALTREX. If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about VALTREX that is written for health professionals. More information is available at www.VALTREX.com.

What are the ingredients in VALTREX?

Active Ingredient: valacyclovir hydrochloride

Inactive Ingredients: carnauba wax, colloidal silicon dioxide, crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, and titanium dioxide.

Rx Only

Distributed by

GlaxoSmithKline

Research Triangle Park, NC 27709

Manufactured by:

GlaxoSmithKline

Research Triangle Park, NC 27709

or

DSM Pharmaceuticals, Inc.

Greenville, NC 27834

©2006, GlaxoSmithKline. All rights reserved.