Pregnancy Risk Category B
How supplied
Tablets: 500 mg, 1 g
Action
Rapidly converts to acyclovir, which in turn becomes incorporated into viral DNA, thereby terminating growth of the DNA chain; inhibits viral DNA polymerase, causing inhibition of viral replication.
Indications & dosage
Herpes zoster infection (shingles)-
Adults: 1 g P.O. t.i.d. for 7 days.
Adjust-a-dose: For renally impaired patients with creatinine clearance of 50 ml/
minute or more, use regular dose; if 30 to 49 ml/minute, 1 g P.O. q 12 hours; if 10 to 29 ml/minute, 1 g P.O. q 24 hours; if below 10 ml/minute, 500 mg P.O. q 24 hours.
For hemodialysis patients, 1 g P.O. after hemodialysis.
Initial episode of genital herpes-
Adults: 1 g P.O. b.i.d. for 10 days.
Adjust-a-dose: For renally impaired patients with creatinine clearance of 30 ml/minute or more, dosage is 1 g P.O. q 12 hours; if 10 to 29 ml/minute, 1 g P.O. q 24 hours; if below 10 ml/minute, 500 mg P.O. q 24 hours.
For hemodialysis patients, 1 g P.O. after hemodialysis.
Recurrent genital herpes-
Adults: 500 mg P.O. b.i.d. for 5 days, given at the first sign or symptom of an episode.
Adjust-a-dose: For renally impaired patients with creatinine clearance of 30 ml/
minute or more, dosage is 500 mg P.O. q 12 hours; if 29 ml/minute or less, 500 mg P.O. q 24 hours.
For hemodialysis patients, 500 mg P.O. after hemodialysis.
Adverse reactions
CNS: headache, asthenia, dizziness.
GI: nausea, vomiting, diarrhea, constipation, abdominal pain, anorexia.
Interactions
Drug-drug. Cimetidine, probenecid: reduced rate but not extent of conversion of valacyclovir to acyclovir and reduced renal clearance of acyclovir, thus increasing acyclovir blood levels. Monitor for possible toxicity.
Effects on diagnostic tests
None reported.
Contraindications
Contraindicated in patients with hypersensitivity or intolerance to valacyclovir, acyclovir, or components of the formulation.
Nursing considerations
Patient teaching
*Liquid contains alcohol. **May contain tartrazine. †Canada ‡Australia §U.K. OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING