Valacyclovir

General

• Type: Antiviral, inhibits DNA polymerase
• Dosage Forms: 500, 1000
• Common Trade Names: Valtrex

Adult Dosing

HSV-1

• Acute episode: 2000mg PO BID x 1 day
• Suppression: 500mg PO Qday

Genital HSV

• 1st episode: 1000mg PO BID x 7-10 days, start within 48-72 hour of symptoms
• recurrence: 500mg PO BID x 3 days, alternative: 1000mg PO qday x 5 days

Shingles

• 1000mg PO TID x 7 days

Pediatric Dosing

Genital HSV

• ≥12 yrs same as adult dosing for adolescents

Special Populations

• Pregnancy Rating: B
• Lactation: Excreted in breastmilk
• Renal Dosing
  • CrCl <10 mL/min: 500 mg/day PO
• Hepatic Dosing: not defined

Contraindications

• Allergy to class/drug

Adverse Reactions

Serious

• TTP, HUS (reported in advanced HIV and transplant patients)
• Acute renal failure (especially if elderly or underlying renal disease)
• Agitation, hallucinations, encephalopathy (higher risk in elderly)

Common

• Headache, dizziness
• Nausea/vomiting, abdominal pain
• Neutropenia, thrombocytopenia, leukopenia
• Elevated LFTs
• Nasopharyngitis
• Dysmenorrhea
• Depression
• Rash
• Alopecia
• EM
• Hypertension
• Tachycardia
• Tremor
• Visual disturbance

Pharmacology

• Half-life: 2-3.3hr
• Metabolism: Hepatic
• Excretion: Urinary
• Mechanism of Action: converted to acyclovir, which competes with deoxyguanosine triphosphate for viral DNA polymerase to inhibit DNA synthesis and viral replication