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Valtrex
valacyclovir
Adult Dosing .
Dosage forms: TAB: 500 mg, 1000 mg
genital HSV, immunocompetent patients
- [1st episode]
- Dose: 1000 mg PO q12h x7-10 days; Start: ASAP within 72h of symptom onset, maximum efficacy within 48h; Info: may extend tx if not healed after 10 days
- [recurrence]
- Dose: 500 mg PO q12h x3 days; Start: ASAP within 24h of symptom onset; Alt: 1000 mg PO qd x5 days
- [suppression]
- Dose: 1000 mg PO qd; Info: give 500 mg PO bid in pregnant patients, start at 36 wk gestation; decr. dose to 500 mg PO qd if <10 outbreaks/y; reassess tx need at 1y
genital HSV, immunocompromised patients
- [1st episode (off-label)]
- Dose: 1000 mg PO q12h x7-10 days; Start: ASAP within 72h of symptom onset, maximum efficacy within 48h; Info: may extend tx if not healed after 10 days
- [recurrence (off-label)]
- Dose: 1000 mg PO q12h x5-10 days
- [suppression]
- Dose: 500 mg PO q12h; Info: reassess tx need at 1y
herpes labialis (cold sores)
- [recurrence]
- Dose: 2000 mg PO q12h x1 day; Start: ASAP after symptom onset
- [suppression (off-label)]
- Dose: 500 mg PO qd; Info: reassess tx need at 4mo
herpes zoster (shingles)
- [1000 mg PO q8h x7 days]
- Start: ASAP within 72h of rash onset, maximum efficacy within 48h; Info: may use for herpes zoster ophthalmicus
renal dosing
- [if usual dose 500 mg qd]
- CrCl <29: 500 mg q48h
- HD: 500 mg q48h, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [if usual dose 500 mg q12h]
- CrCl <29: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [if usual dose 1000 mg qd]
- CrCl <29: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [if usual dose 1000 mg q12h]
- CrCl 10-29: 1000 mg qd; CrCl <10: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [if usual dose 1000 mg q8h]
- CrCl 30-49: 1000 mg q12h; CrCl 10-29: 1000 mg qd; CrCl <10: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [if usual dose 2000 mg q12h x1 day]
- CrCl 30-49: 1000 mg q12h x1 day; CrCl 10-29: 500 mg q12h x1 day; CrCl <10: 500 mg x1
- HD: 500 mg x1 after dialysis; no supplement; PD: 500 mg q48h; no supplement
hepatic dosing
- [no adjustment]
Peds Dosing .
- Dosage forms: TAB: 500 mg, 1000 mg
herpes labialis (cold sores)
- [12 yo and older]
- Dose: 2000 mg PO q12h x1 day; Start: ASAP after symptom onset
varicella (chicken pox), immunocompetent patients
- [2 yo and older]
- Dose: 20 mg/kg/dose PO q8h x5 days; Start: ASAP within 24h of rash onset; Max: 1000 mg/dose
genital HSV (off-label)
- [1st episode, preadolescents >45 kg and adolescents]
- Dose: 1000 mg PO q12h x10 days; Start: ASAP within 72h of symptom onset, maximum efficacy within 48h; Info: may extend tx if not healed after 10 days
- [recurrence, preadolescents >45 kg and adolescents]
- Dose: 500 mg PO q12h x3 days; Alt: 1 g q24h x5 days; Start: ASAP within 24h of symptom onset
- [suppression, preadolescents >45 kg and adolescents]
- Dose: 1000 mg PO qd; Info: give 500 mg PO bid in pregnant patients, start at 36 wk gestation; decr. dose to 500 mg PO qd if <10 outbreaks/y; reassess tx need at 1y
renal dosing
- [varicella (chicken pox)]
- CrCl 30-50: give usual dose q12h; CrCl 10-29: give usual dose q24h; CrCl <10: give 50% usual dose q24h
- HD: give 50% usual dose q24h, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: give 50% usual dose q24h; no supplement
- [all other indications, usual dose 500 mg q12h]
- CrCl <29: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [all other indications, usual dose 1000 mg qd]
- CrCl <29: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [all other indications, usual dose 1000 mg q12h]
- CrCl 10-29: 1000 mg qd; CrCl <10: 500 mg qd
- HD: 500 mg qd, on dialysis days administer after dialysis; consider supplement if next maintenance dose not due right after dialysis; PD: 500 mg q48h; no supplement
- [all other indications, usual dose 2000 mg q12h x1 day]
- CrCl 30-49: 1000 mg q12h x1 day; CrCl 10-29: 500 mg q12h x1 day; CrCl <10: 500 mg x1
- HD: 500 mg x1 after dialysis; no supplement; PD: 500 mg q48h; no supplement
hepatic dosing
- [no adjustment]
Contraindications / Cautions .
- hypersensitivity to drug or ingredient
- hypersensitivity to acyclovir
- caution: hypersensitivity to famciclovir
- caution: hypersensitivity to penciclovir
- caution: immunocompromised patients
- caution: HIV disease, advanced
- caution: renal impairment
- caution: nephrotoxic agent use, concurrent
- caution: elderly patients
- caution: dehydration
Drug Interactions .
Overview
valacyclovir
viral DNA polymerase inhibitor
- CYP1A2 inhibitor, weak
- impairs immunomodulatory viral infective agent
- lowers seizure threshold
- nephrotoxicity
- valacyclovir (prodrug) converted to acyclovir
Contraindicated
- cidofovir
- fezolinetant
Avoid/Use Alternative
- acyclovir
- aldesleukin
- amifampridine
- amikacin
- amikacin inhaled
- bumetanide
- clofarabine
- foscarnet
- ganciclovir
- gentamicin
- mannitol
- methotrexate
- oxaliplatin
- pentamidine
- polymyxin B
- streptomycin
- streptozocin
- talimogene laherparepvec
- tenofovir disoproxil
- tizanidine
- tobramycin
- tobramycin inhaled
- valacyclovir
- valganciclovir
Monitor/Modify Tx
- adefovir dipivoxil
- alectinib
- aliskiren
- amiloride
- aminophylline
- amphotericin
- anthrax immune globulin
- aspirin
- auranofin
- axitinib
- azilsartan medoxomil
- balsalazide
- benazepril
- bendamustine
- bevacizumab
- bleomycin
- botulism immune globulin
- bupropion
- cabozantinib
- caffeine citrate
- candesartan cilexetil
- capecitabine
- captopril
- carboplatin
- carfilzomib
- celecoxib
- chlorothiazide
- chlorthalidone
- cisplatin
- clindamycin
- clozapine
- colistimethate
- copper histidinate
- creatine
- cyclophosphamide
- cyclosporine
- cytomegalovirus immune globulin
- deferasirox
- deferoxamine
- diclofenac
- diclofenac topical
- diflunisal
- enalapril
- enalaprilat
- ethacrynic acid
- etodolac
- everolimus
- fenoprofen
- flucytosine
- flurbiprofen
- fosinopril
- furosemide
- hydrochlorothiazide
- hydroxocobalamin IV
- ibuprofen
- ibuprofen lysine
- ifosfamide
- immune globulin
- indapamide
- indomethacin
- iodixanol
- iohexol
- iomeprol
- iopamidol
- iopromide
- iothalamate meglumine
- ioversol
- irbesartan
- ketoprofen
- ketorolac
- lenvatinib
- lifileucel
- lisinopril
- lithium
- lomustine
- losartan
- lutetium Lu 177 vipivotide tetraxetan
- magnesium citrate
- magnesium salicylate
- meclofenamate
- mefenamic acid
- meloxicam
- mesalamine
- mesalamine rectal
- metolazone
- mitomycin
- moexipril
- nabumetone
- naproxen
- neomycin
- nusinersen
- olmesartan medoxomil
- olsalazine
- oxaprozin
- pamidronate
- paromomycin
- pazopanib
- pemetrexed
- penicillamine
- pentostatin
- perindopril
- piroxicam
- plazomicin
- polyethylene glycol
- polyethylene glycol/electrolytes
- quinapril
- ramipril
- ramucirumab
- Rho(D) immune globulin
- rituximab
- ropeginterferon alfa-2b
- salsalate
- sirolimus
- sitagliptin
- sparsentan
- spironolactone
- sulfate bowel prep
- sulindac
- sunitinib
- tacrolimus
- telavancin
- telmisartan
- temsirolimus
- tenofovir alafenamide
- theophylline
- tiopronin
- tivozanib
- tolmetin
- torsemide
- trandolapril
- triamterene
- vaccinia immune globulin
- valsartan
- vancomycin
- varicella vaccine, live
- voclosporin
- warfarin
- willow bark
- ziv-aflibercept
- zoledronic acid
- zonisamide
Caution Advised
- acetazolamide
- alosetron
- brivaracetam
- busulfan
- cannabidiol
- carbamazepine
- cenobamate
- chlorambucil
- cimetidine
- clobazam
- clomipramine
- clonazepam
- clorazepate
- diazepam
- emtricitabine
- eslicarbazepine acetate
- ethosuximide
- felbamate
- fenfluramine
- fosphenytoin
- gabapentin
- ganaxolone
- hydroxychloroquine
- lacosamide
- lamotrigine
- levetiracetam
- lorazepam
- meperidine
- methsuximide
- midazolam
- oxcarbazepine
- perampanel
- phenobarbital
- phenytoin
- pirfenidone
- pregabalin
- primidone
- promethazine
- roflumilast
- roflumilast topical
- rufinamide
- sodium picosulfate
- stiripentol
- tiagabine
- topiramate
- tramadol
- treosulfan
- valproic acid
- vigabatrin
- vorasidenib
Adverse Reactions .
Serious Reactions
- Stevens-Johnson syndrome
- drug reaction with eosinophilia and systemic symptoms
- toxic epidermal necrolysis
- acute generalized exanthematous pustulosis
- erythema multiforme
- acute renal failure
- thrombocytopenia
- aplastic anemia
- anaphylaxis
- TTP
- hemolytic uremic syndrome
- delirium
- aggressive behavior
- psychosis
- encephalopathy
- seizures
Common Reactions
- nausea
- headache
- vomiting
- dizziness
- abdominal pain
- dysmenorrhea
- arthralgia
- depression
- neutrophils decr.
- ALT or AST elevated
- fatigue
- rash
- alk phos elevated
- platelets decr.
- photosensitivity
- diarrhea (peds patients)
- fever (peds patients)
Safety/Monitoring .
Monitoring Parameters
Cr at baseline
Look/Sound-Alike Drug Names
Valtrex confused with: cephalexin; divalproex; Keflex; Urex; Valcyte; Zovirax
valACYclovir confused with: acyclovir; ganciclovir; valdecoxib; valGANciclovir; vancomycin
Pregnancy/Lactation .
Pregnancy
Clinical Summary
may use during pregnancy; no known risk of teratogenicity based on limited human data and on animal data at 4x and 7x MRHD
Lactation
Clinical Summary
may use while breastfeeding; no known risk of infant harm based on limited human data and drug properties; no human data available to assess effects on milk production
Pharmacology .
Metabolism: for valacyclovir: GI tract, liver; CYP450: none
Excretion: for valacyclovir: feces 47.1%, urine 45.6% (<1% unchanged); Half-life: <30min (valacyclovir), 2.5-3.3h (acyclovir), 14h (acyclovir in ESRD)
Subclass: Herpes/Varicella/Zoster (HSV/VZV)
Mechanism of Action
for valacyclovir: prodrug converted to acyclovir, which inhibits DNA polymerase; incorporates into viral DNA
Formulary .
No Formulary Selected
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