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ValACYclovir

Medically reviewed on Nov 15, 2018

Pronunciation

See also: Aubagio

(val ay SYE kloe veer)

Index Terms

  • Valacyclovir HCl
  • Valacyclovir Hydrochloride

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral:

Valtrex: 500 mg [contains fd&c blue #2 aluminum lake]

Valtrex: 1 g [scored; contains fd&c blue #2 aluminum lake]

Generic: 500 mg, 1 g

Brand Names: U.S.

  • Valtrex

Pharmacologic Category

  • Antiviral Agent
  • Antiviral Agent, Oral

Pharmacology

Valacyclovir is rapidly and nearly completely converted to acyclovir by intestinal and hepatic metabolism. Acyclovir is converted to acyclovir monophosphate by virus-specific thymidine kinase then further converted to acyclovir triphosphate by other cellular enzymes. Acyclovir triphosphate inhibits DNA synthesis and viral replication by competing with deoxyguanosine triphosphate for viral DNA polymerase and being incorporated into viral DNA.

Absorption

Rapid

Distribution

Acyclovir is widely distributed throughout the body including brain, kidney, lungs, liver, spleen, muscle, uterus, vagina, and CSF

Metabolism

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

Excretion

Urine, primarily as acyclovir (89%); Note: Following oral administration of radiolabeled valacyclovir, 46% of the label is eliminated in the feces (corresponding to nonabsorbed drug), while 47% of the radiolabel is eliminated in the urine.

Time to Peak

Children: 1.4 to 2.6 hours; Adults: 1.5 hours

Half-Life Elimination

Normal renal function: Children: 1.3 to 2.5 hours, slower clearance with increased age; Adults: 2.5 to 3.3 hours (acyclovir), ~30 minutes (valacyclovir); End-stage renal disease: 14 to 20 hours (acyclovir); During hemodialysis: 4 hours

Protein Binding

~14% to 18%

Special Populations: Children

Cmax ~4.2 mcg/mL in children 1 month to <12 years of age.

Use: Labeled Indications

Treatment of herpes zoster (shingles) in immunocompetent patients; treatment of first-episode and recurrent genital herpes in immunocompetent patients; suppression of recurrent genital herpes and reduction of transmission of genital herpes in immunocompetent patients; suppression of genital herpes in HIV-infected individuals; treatment of herpes labialis (cold sores); chickenpox in immunocompetent children

Off Label Uses

B virus (Cercopithecine herpesvirus 1)

Based on the Infectious Diseases Society of America Guidelines on the Management of Encephalitis, valacyclovir is effective and recommended as postexposure prophylaxis for individuals who have a high-risk exposure to B virus.

Clinical experience also suggests the utility of valacyclovir in treatment of B virus infection, after initial parenteral treatment [Cohen 2002].

Bell palsy, new onset (adjunct therapy)

Based on the American Academy of Neurology evidence-based guideline update, steroids and antivirals for Bell palsy, and American Academy of Otolaryngology- Head and Neck Surgery clinical practice guideline on Bell palsy, valacyclovir may be considered as an adjunct to oral glucocorticoids for treatment of Bell palsy in patients who present within 72 hours of symptom onset.

Cytomegalovirus, prevention in allogeneic hematopoietic cell transplant recipients

Based on the American Society of Blood Marrow Transplantation and IDSA Guidelines for Preventing Infectious Complications among Hematopoietic Cell Transplantation Recipients, the use of valacyclovir to prevent cytomegalovirus (CMV) reactivation in allogeneic hematopoietic cell transplant (HCT) patients is effective and recommended.

Herpes simplex virus, keratitis

Based on the American Academy of Ophthalmology Herpes Simplex Virus Keratitis Treatment Guideline, valacyclovir is an effective and recommended agent for treatment and prevention of recurrence of herpes simplex virus (HSV) keratitis.

HSV, prevention in immunocompromised patients

Based on the American Society of Blood Marrow Transplantation and IDSA Guidelines for Preventing Infectious Complications among Hematopoietic Cell Transplant Recipients, valacyclovir is an effective and recommended alternative agent to prevent HSV reactivation (early and late) in hematopoietic cell transplant patients.

Based on the ASCO and IDSA guidelines for antimicrobial prophylaxis for adult patients with cancer-related immunosuppression, valacyclovir is an effective and recommended agent to prevent HSV reactivation in patients undergoing leukemia induction therapy.

Clinical experience suggests the utility of valacyclovir for prevention of HSV in seropositive solid organ transplant recipients [Wilck 2013].

Herpes zoster ophthalmicus

Data from a multicenter, randomized study support the use of valacyclovir in the management of herpes zoster ophthalmicus in immunocompetent patients [Colin 2000].

Varicella zoster virus, acute retinal necrosis

Data from a limited number of patients studied suggest that valacyclovir may be beneficial for the treatment of acute retinal necrosis (ARN) caused by varicella zoster virus (VZV) [Aizman 2007], [Aslanides 2002].

Based on the US Department of Health and Human Services (HHS) Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents, valacyclovir, after initial treatment with acyclovir IV and intravitreal ganciclovir, is an effective and recommended agent in the management of VZV acute retinal necrosis (ARN) in HIV-infected patients.

VZV, prevention in immunocompromised patients

Based on the American Society of Blood Marrow Transplantation and IDSA Guidelines for Preventing Infectious Complications among Hematopoietic Cell Transplant Recipients, valacyclovir is an effective and recommended alternative agent to prevent VZV infection in seronegative HCT recipients (<24 months after HCT or >24 months and on immunosuppressive therapy or have chronic graft-versus-host disease) who cannot receive varicella-zoster immune globulin and are exposed to varicella, zoster, or to a vaccinee who develops a rash and to prevent VZV reactivation in seropositive allogeneic and autologous HCT recipients.

Clinical experience suggests the utility of valacyclovir for prevention of VZV in seropositive solid organ transplant recipients who are not already receiving CMV or HSV prophylaxis [Pergam 2013].

Contraindications

Hypersensitivity to valacyclovir, acyclovir, or any component of the formulation

Dosing: Adult

B virus (Cercopithecine herpesvirus 1) (off-label use):

Postexposure prophylaxis: Oral: 1 g 3 times daily for 14 days (Cohen 2002; IDSA [Tunkel 2008])

Treatment (after initial parenteral therapy): Oral: 1 g 3 times daily for 6 to 12 months, then may decrease to 500 mg once or twice daily, possibly for an indefinite duration. Note: Initial treatment with IV therapy should be continued until symptoms resolve and ≥2 sets of cultures (held for 10 to 14 days) are negative, then switch to oral antiviral therapy (Cohen 2002).

Bell palsy, new-onset (adjunct therapy) (off-label use): Oral: 1 g 3 times daily for 7 days in combination with corticosteroids; begin within 3 days of symptom onset (AAO-HSNF [Baugh 2013]; Axelsson 2003; Engstrom 2008). Note: Antiviral therapy alone is not recommended (AAN [Gronseth 2012]; AAO-HSNF [Baugh 2013]); some experts only recommend addition of an antiviral to steroid therapy in patients with severe Bell palsy (Hato 2008; Ronthal 2018).

Cytomegalovirus (CMV), prevention in allogeneic hematopoietic cell transplant recipients (alternative agent) (off-label use): High-risk patients (CMV-seropositive HCT recipients and CMV-seronegative recipients with a CMV-seropositive donor): Oral: 2 g 3 to 4 times daily, beginning at engraftment and continued to day 100 (ASBMT/IDSA [Tomblyn 2009]) or 2 g 3 times daily, started after initial therapy with IV ganciclovir from day -8 to day -2 prior to transplant, and continued until engraftment or longer in patients on glucocorticoids (Milano 2001; Wingard 2018). Note: Both strategies should be combined with screening for CMV reactivation (ASBMT/IDSA [Tomblyn 2009]; Wingard 2018).

Herpes simplex virus (HSV), keratitis (off-label use):

Prophylaxis (for recurrent keratitis): Oral: 500 mg once daily for ≥1 year (optimal duration not established) (AAO/OMIG [White 2014])

Treatment:

Endothelial keratitis: Oral: 500 mg twice daily for 7 to 10 days in combination with a therapeutic dose of topical corticosteroid, then reduce to 500 mg once daily and continue for the duration of corticosteroid treatment (AAO/OMIG [White 2014])

Epithelial keratitis, dendritic: Oral: 500 mg twice daily for 7 to 10 days (AAO/OMIG [White 2014])

Epithelial keratitis, geographic: Oral: 1 g 3 times daily for 14 to 21 days (AAO/OMIG [White 2014])

Stromal keratitis, without epithelial ulceration: Oral: 500 mg once daily in combination with a therapeutic dose of topical corticosteroid; continue for the duration of corticosteroid treatment (AAO/OMIG [White 2014])

Stromal keratitis, with epithelial ulceration: Oral: 1 g 3 times daily for 7 to 10 days in combination with a therapeutic dose of topical corticosteroid, then reduce to 500 mg once daily and continue for the duration of corticosteroid treatment (AAO/OMIG [White 2014])

HSV, mucocutaneous infection:

Genital: Oral:

Immunocompetent patients:

Treatment, initial episode: 1 g twice daily for 7 to 10 days; extend treatment duration if lesion has not completely healed after 10 days (CDC [Workowski 2015]).

Treatment, recurrent episode: 500 mg twice daily for 3 days or 1 g once daily for 5 days, initiated within 1 day of lesion onset or during the prodrome (when applicable) (CDC [Workowski 2015]).

Suppressive therapy: 500 mg or 1 g once daily for up to 12 months. Note: 500 mg once daily may be less effective in patients who experience ≥10 recurrences per year (CDC [Workowski 2015]).

Immunocompromised patients (including HIV-infected):

Treatment, initial or recurrent episode: 1 g twice daily for 5 to 10 days; extend treatment duration if lesions have not completely healed after 10 days. Note: Severe disease should be treated with IV acyclovir for the first 2 to 7 days; may switch to valacyclovir when lesions begin to regress and continue for at least 10 days and until complete resolution (CDC [Workowski 2015]; HHS [OI adult 2018]).

Suppressive therapy: 500 mg twice daily. Reserve for use in patients with severe or frequent recurrences; annually reevaluate ongoing need for suppressive therapy (CDC [Workowski 2015]; HHS [OI adult 2018]).

Pregnant females:

Treatment, initial episode: 1 g twice daily for 7 to 10 days; extend treatment duration if lesion has not completely healed after 10 days (ACOG 2007).

Treatment, recurrent episode (symptomatic): 500 mg twice daily for 3 days or 1 g once daily for 5 days (ACOG 2007). Note: Some experts recommend reserving treatment of recurrent episodes for patients with severe symptoms and/or frequent occurrences (Riley 2018).

Suppressive therapy, if a genital lesion occurs anytime during pregnancy: 500 mg twice daily, beginning at 36-weeks gestation and continued until onset of delivery (ACOG 2007; CDC [Workowski 2015]). Note: Some experts recommend considering the initiation of suppression earlier than 36 weeks for women who have a first-episode lesion during the third trimester (Riley 2018).

Orolabial: Oral: Note: Initiate therapy at earliest symptom (eg, tingling, itching, burning).

Immunocompetent patients:

Treatment, initial or recurrent episode: 2 g twice daily for 1 day

Suppressive therapy: 500 mg or 1 g once daily (Baker 2003; Gilbert 2007). Reserve for use in patients with virologically confirmed recurrent HSV when recurrences are frequent and/or bothersome (eg, disfiguring lesions, pain) or associated with serious systemic complications (Klein 2018).

Immunocompromised patients (including HIV-infected):

Treatment, initial or recurrent episode: 1 g twice daily for 5 to 10 days (HHS [OI adult 2018])

Suppressive therapy: 500 mg twice daily. Reserve for use in patients with severe or frequent recurrences; annually reevaluate ongoing need for suppressive therapy (HHS [OI adult 2018]).

HSV, prevention in immunocompromised patients (off-label use):

Seropositive HCT recipients (allogeneic or autologous) or seropositive patients undergoing leukemia induction therapy: Oral: 500 mg twice daily (ASBMT/IDSA [Tomblyn 2009]; Wingard 2018). Initiate at the beginning of conditioning therapy and continue until recovery of WBC count or resolution of mucositis, whichever occurs later; duration may be extended in patients with frequent recurrent HSV infections or those with graft-vs-host disease (GVHD), or can be continued as varicella zoster virus prophylaxis for up to 1 year (ASBMT/IDSA [Tomblyn 2009]; ASCO/IDSA [Taplitz 2018]).

Solid organ transplant recipients (HSV-seropositive patients who do not require CMV prophylaxis):Oral: 500 mg twice daily for at least 1 month (Wilck 2013); some experts recommend continuing for 3 to 6 months after transplantation and during periods of lymphodepletion associated with treatment of rejection (Fishman 2018).

Herpes zoster (shingles), treatment:

Immunocompetent patients: Oral: 1 g 3 times daily for 7 days. Initiate at earliest sign or symptom (most effective when initiated ≤48 hours of rash onset); may initiate treatment >72 hours after rash onset if new lesions are continuing to appear (Cohen 1999).

Immunocompromised patients (including HIV-infected): Oral:

Acute localized dermatomal: 1 g 3 times daily for 7 to 10 days; consider longer duration if lesions resolve slowly (HHS [OI adult 2018]; Pergam 2013).

Extensive cutaneous lesions or visceral involvement: 1 g 3 times daily to complete a 10- to 14-day course. Note: Patients should receive initial treatment with IV acyclovir; may switch to valacyclovir when clinical improvement occurs (ie, formation of new lesions has ceased, signs/symptoms of visceral infection are improving) (HHS [OI adult 2018]; Pergam 2013).

Herpes zoster ophthalmicus (off-label use): Immunocompetent patients: Oral: 1 g 3 times daily for 7 days (Colin 2000). Note: Immunocompromised patients and patients who require hospitalization for sight-threatening disease should receive IV acyclovir (Albrecht 2018b).

Varicella (chickenpox), treatment (uncomplicated): Oral: 1 g 3 times daily, ideally initiated within 24 hours of symptom onset (may be initiated later if patient still has active skin lesions); continue treatment for 5 to 7 days (HHS [OI adult 2018]) or until all lesions have crusted (Albrecht 2018a). Note: Immunocompromised patients generally require IV acyclovir; however, for patients with uncomplicated or mild disease (<50 lesions), some experts treat with valacyclovir (Albrecht 2018a; HHS [OI adult 2018]).

Varicella zoster virus (VZV), acute retinal necrosis (off-label use): Oral: 1 g 3 times daily for 6 weeks following initial treatment with IV acyclovir (Aizman 2007; Albrecht 2018b; Aslanides 2002; HHS [OI adult 2018]); in HIV-infected patients, some experts recommend addition of intravitreal ganciclovir (HHS [OI adult 2018]).

VZV, prevention in immunocompromised patients (off-label use):

HCT recipients (allogeneic and autologous): Oral:

Postexposure prophylaxis (seronegative patients who cannot receive varicella-zoster immune globulin and are exposed to varicella zoster, herpes zoster, or a VZV vaccinee who develops a rash): 1 g 3 times daily; initiate within 96 hours (preferably, within 48 hours) of exposure and continue until 22 days after exposure. Note: Indicated in HCT recipients who are <24 months after HCT or >24 months after HCT and on immunosuppressive therapy or have chronic GVHD (ASBMT/IDSA [Tomblyn 2009]).

Prevention of VZV reactivation in seropositive patients: 500 mg twice daily for 1 year following transplantation; may extend duration in patients requiring ongoing immunosuppression (some experts continue prophylaxis in these patients until 6 months after discontinuation of all systemic immunosuppression) (ASBMT/IDSA [Tomblyn 2009]).

Solid organ transplant recipients (VZV seropositive patients who do not require CMV prophylaxis): Oral: 500 mg twice daily for 3 to 6 months after transplantation and during periods of lymphodepletion associated with treatment of rejection (Fishman 2018; Pergam 2013).

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Herpes labialis (cold sores), treatment in immunocompetent patients: Children ≥12 years of age and Adolescents: Oral: 2,000 mg every 12 hours for 1 day (2 doses); initiate at earliest symptom onset

Herpes labialis (cold sores), treatment in HIV-infected patients (off-label use): Adolescents: 1,000 mg twice daily for 5 to 10 days (HHS [OI adult 2018])

Herpes simplex virus, genital infection in HIV-infected patients: Adolescents (off-label population): Oral:

Initial or recurrent episodes (off-label use): 1,000 mg twice daily for 5 to 14 days (HHS [OI adult 2015])

Chronic suppressive therapy (off-label dose): 500 mg twice daily; continue indefinitely regardless of CD4 count in patients with severe recurrences or in patients who want to minimize frequency of recurrences (HHS [OI adult 2015])

Varicella (chickenpox): Immunocompetent patients: Children ≥2 years of age and Adolescents: Oral: 20 mg/kg/dose 3 times daily for 5 days (maximum: 1,000 mg 3 times daily)

Dosing: Renal Impairment

Herpes zoster: Adults:

CrCl 30 to 49 mL/minute: 1 g every 12 hours

CrCl 10 to 29 mL/minute: 1 g every 24 hours

CrCl <10 mL/minute: 500 mg every 24 hours

Genital herpes: Adults:

US labeling:

Initial episode:

CrCl 10 to 29 mL/minute: 1 g every 24 hours

CrCl <10 mL/minute: 500 mg every 24 hours

Recurrent episode: CrCl <29 mL/minute: 500 mg every 24 hours

Suppressive therapy: CrCl <29 mL/minute:

For usual dose of 1 g every 24 hours or 500 mg every 12 hours, decrease dose to 500 mg every 24 hours

For usual dose of 500 mg every 24 hours, decrease dose to 500 mg every 48 hours

Canadian labeling:

Initial episode:

CrCl 10 to 29 mL/minute: 1 g every 24 hours

CrCl <10 mL/minute: 500 mg every 24 hours

Recurrent episode:

CrCl 10 to 29 mL/minute: 500 mg every 24 hours

CrCl <10 mL/minute: 500 mg every 24 hours

Suppressive therapy:

CrCl 10 to 29 mL/minute:

Immunocompetent or HIV-infected patients: 500 mg every 24 hours

Immunocompetent patients with ≤9 recurrences/year: 500 mg every 48 hours

CrCl <10 mL/minute:

Immunocompetent or HIV-infected patients: 500 mg every 24 hours

Immunocompetent patients with ≤9 recurrences/year: 500 mg every 48 hours

Herpes labialis (cold sores): Adolescents and Adults (US labeling) or Adults (Canadian labeling):

CrCl 30 to 49 mL/minute: 1 g every 12 hours for 2 doses

CrCl 10 to 29 mL/minute: 500 mg every 12 hours for 2 doses

CrCl <10 mL/minute: 500 mg as a single dose

Hemodialysis: Dialyzable (~33% removed during 4-hour session); administer dose postdialysis

Chronic ambulatory peritoneal dialysis/continuous arteriovenous hemofiltration dialysis: Pharmacokinetic parameters are similar to those in patients with ESRD; supplemental dose not needed following dialysis

Dosing: Hepatic Impairment

No dosage adjustment necessary.

Extemporaneously Prepared

50 mg/mL Oral Suspension (ASHP Standard Concentration) (ASHP 2017)

A 50 mg/mL oral suspension may be made with caplets, Ora-Plus, and either Ora-Sweet or Ora-Sweet SF. Crush eighteen 500 mg caplets in a mortar and reduce to a fine powder. Add 5 mL portions of Ora-Plus (40 mL total) and mix to a uniform paste; transfer to a 180 mL calibrated amber glass bottle, rinse mortar with 10 mL of Ora-Plus 5 times, then add quantity of syrup (Ora-Sweet or Ora-Sweet SF) sufficient to make 180 mL. Label "shake well" and "refrigerate." Stable for 21 days refrigerated.

Fish DN, Vidaurri VA, and Deeter RG, "Stability of Valacyclovir Hydrochloride in Extemporaneously Prepared Oral Liquids," Am J Health Syst Pharm, 1999, 56(19):1957-60.10554914

Administration

If GI upset occurs, administer with meals.

Storage

Store at 15°C to 25°C (59°F to 77°F).

Drug Interactions

CloZAPine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of CloZAPine. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Monitor therapy

Foscarnet: May enhance the nephrotoxic effect of Acyclovir-Valacyclovir. Avoid combination

Mycophenolate: Acyclovir-Valacyclovir may increase the serum concentration of Mycophenolate. Mycophenolate may increase the serum concentration of Acyclovir-Valacyclovir. Monitor therapy

Talimogene Laherparepvec: Antiherpetic Antivirals may diminish the therapeutic effect of Talimogene Laherparepvec. Monitor therapy

Tenofovir Products: Acyclovir-Valacyclovir may increase the serum concentration of Tenofovir Products. Tenofovir Products may increase the serum concentration of Acyclovir-Valacyclovir. Monitor therapy

TiZANidine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of TiZANidine. Management: Avoid these combinations when possible. If combined use is necessary, initiate tizanidine at an adult dose of 2 mg and increase in 2 to 4 mg increments based on patient response. Monitor for increased effects of tizanidine, including adverse reactions. Consider therapy modification

Varicella Virus Vaccine: Acyclovir-Valacyclovir may diminish the therapeutic effect of Varicella Virus Vaccine. Management: When possible, avoid use of acyclovir or valacyclovir within the 24 hours prior to administration of the varicella vaccine, and avoid use of these antiviral agents for 14 days after vaccination. Avoid combination

Zidovudine: Acyclovir-Valacyclovir may enhance the CNS depressant effect of Zidovudine. Monitor therapy

Zoster Vaccine (Live/Attenuated): Acyclovir-Valacyclovir may diminish the therapeutic effect of Zoster Vaccine (Live/Attenuated). Management: When possible, discontinue antiviral agents with anti-zoster activity (i.e., acyclovir, valacyclovir, famciclovir) for at least 24 hours prior to and 14 days after receiving a live attenuated zoster vaccine. Avoid combination

Adverse Reactions

>10%:

Central nervous system: Headache (13% to 38%)

Gastrointestinal: Nausea (5% to 15%), abdominal pain (1% to 11%)

Hepatic: Increased serum AST (2% to 16%), increased serum ALT (≤14%)

Respiratory: Nasopharyngitis (≤16%)

1% to 10%:

Central nervous system: Fatigue (≤8%), depression (≤7%), dizziness (2% to 4%)

Dermatologic: Skin rash (≤8%)

Endocrine & metabolic: Dehydration (children: 2%)

Gastrointestinal: Vomiting (≤6%), diarrhea (children: 5%; adults: <1%)

Genitourinary: Dysmenorrhea (≤8%)

Hematologic & oncologic: Thrombocytopenia (≤3%), leukopenia (≤1%; mild)

Hepatic: Increased serum alkaline phosphatase (≤4%)

Infection: Herpes simplex infection (children: 2%)

Neuromuscular & skeletal: Arthralgia (≤6%)

Respiratory: Rhinorrhea (children: 2%)

Miscellaneous: Fever (children: 4%)

<1%, postmarketing, and/or case reports: Aggressive behavior, agitation, alopecia, anemia, aplastic anemia, ataxia, brain disease, coma, confusion, delirium, dysarthria, erythema multiforme, facial edema, hallucination (auditory and visual), hemolytic-uremic syndrome, hepatitis, hypersensitivity reaction (acute; includes anaphylaxis, angioedema, dyspnea, pruritus, skin rash, urticaria), hypertension, hypersensitivity angiitis, increased serum creatinine, loss of consciousness, mania, psychosis, renal failure, renal pain, seizure, skin photosensitivity, tachycardia, thrombotic thrombocytopenic purpura, tremor, urinary urgency, visual disturbance

Warnings/Precautions

Concerns related to adverse effects:

• CNS effects: CNS adverse effects (including agitation, hallucinations, confusion, delirium, seizures, and encephalopathy) have been reported in both adult and pediatric patients with or without renal dysfunction. Elderly patients are more likely to experience CNS adverse effects.

• Thrombotic microangiopathy: Has occurred in immunocompromised patients (at doses of 8 g/day).

Disease-related concerns:

• Renal impairment: Use caution in patients with renal impairment, the elderly, and/or those receiving nephrotoxic agents. Acute renal failure and CNS effects have been observed in patients with renal dysfunction; dose adjustment may be required. Precipitation in renal tubules may occur; maintain adequate hydration.

Special populations:

• Elderly: Use with caution in the elderly; CNS effects have been reported.

• Immunocompromised patients: Advanced HIV (CD4 <100 cells/mm3): Safety and efficacy have not been established for treatment/suppression of recurrent genital herpes or disseminated herpes in patients with profound immunosuppression.

Other warnings/precautions:

• Appropriate use: For cold sores, treatment should begin with earliest symptom (tingling, itching, burning). For genital herpes, treatment should begin as soon as possible after the first signs and symptoms (within 72 hours of onset of first diagnosis or within 24 hours of onset of recurrent episodes). For herpes zoster, treatment should begin within 72 hours of onset of rash. For chickenpox, treatment should begin with earliest sign or symptom.

Monitoring Parameters

Urinalysis, BUN, serum creatinine, liver enzymes, and CBC

Pregnancy Risk Factor

B

Pregnancy Considerations

Adverse events were not observed in animal reproduction studies. Valacyclovir is metabolized to acyclovir. In a pharmacokinetic study, maternal acyclovir serum concentrations were higher in pregnant women receiving valacyclovir than those given acyclovir for the suppression of recurrent herpes simplex virus (HSV) infection late in pregnancy. Amniotic fluid concentrations were also higher; however, there was no evidence that fetal exposure differed between the groups (Kimberlin 1998). Data from an acyclovir pregnancy registry has shown no increased rate of birth defects than that of the general population; however, the registry is small and the manufacturer notes that use during pregnancy is only warranted if the potential benefit to the mother justifies the risk of the fetus. Because more data is available for acyclovir, that agent is preferred for the treatment of genital herpes in pregnant women (CDC [Workowski 2015]); however, valacyclovir may be considered for use due to its simplified dosing schedule (HHS [OI adult 2015]). Pregnant women who have a history of genital herpes recurrence, suppressive therapy is recommended starting at 36-weeks gestation (HHS [OI adult 2016]).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience headache, nausea, vomiting, dizziness, fatigue, or abdominal pain. Have patient report immediately to prescriber signs of kidney problems (urinary retention, blood in urine, change in amount of urine passed, or weight gain), confusion, behavioral changes, mood changes, hallucinations, tremors, difficulty moving, rigidity, or signs of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (bruising or bleeding; feeling very tired or weak; dark urine or yellow skin or eyes; pale skin; change in the amount of urine passed; vision changes; change in strength on one side is greater than the other, trouble speaking or thinking, change in balance; or fever) (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.