Classifications: antiviral; Therapeutic: antiviral
Pregnancy Category: B
500 mg tablets
An antiviral agent hydrolyzed in the intestinal wall or liver to acyclovir; interferes with viral DNA synthesis. Because
of increased GI absorption, the plasma level of this drug is substantially higher than that of acyclovir when both are taken
Active against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2), varicella zoster virus, and cytomegalovirus. Inhibits
Herpes zoster (shingles) in immunocompetent adults. Treatment and suppression of recurrent genital herpes; suppression of
recurrent herpes in HIV-positive patients; treatment of cold sores.
Hypersensitivity to or intolerance of valacyclovir or acyclovir; children <2 y.
Renal impairment, patients receiving nephrotoxic drugs, advanced HIV disease, allogeneic bone marrow transplant and renal
transplant recipients, treatment of disseminated herpes zoster, immunocompromised patients, pregnancy (category B); lactation.
Route & Dosage
Adult: PO 1 g (2 x 500 mg) t.i.d. for 7 d, start within 48 h of onset of zoster rash
Clcr 3049 mL/min: 1 g q12h; 1029 mL/min: 1 g q24h; <10 mL/min: 500 mg q24h
Treatment of Recurrent Genital Herpes
Adult: PO 500 mg b.i.d. x 3 d
Clcr ≤29 mL/min: 500 mg q.d.
Suppression of Recurrent Genital Herpes
Adult: PO 1 g q.d.
Treatment of Cold Sores
Adult: PO 2 g 12 h x 2 doses
- Start drug as soon as possible after diagnosis of herpes zoster, preferably within 48 h of onset of rash.
- Note: Dosage reduction is recommended for patients with renal impairment.
- Give valacyclovir after hemodialysis.
- Store at 15°30° C (59°86° F).
Adverse Effects (≥1%)CNS: Headache,
weakness, somnolence, dizziness, fatigue
, lethargy, confusion. GI: Nausea, vomiting, diarrhea,
abdominal pain, dyspepsia, flatulence. Urogenital:
Glomerulonephritis, renal tubular damage, acute renal failure. Skin:
Rash, urticaria, pruritus.
InteractionsDrug: Probenecid, cimetidine
decrease valacyclovir elimination. Zidovudine
may cause increased drowsiness and lethargy.
Rapidly absorbed from GI tract; 54% reaches systemic circulation as acyclovir. Peak:
1.5 h. Distribution:
13.517.9% bound to plasma
proteins; distributes into plasma, cerebrospinal fluid, saliva, and major body organs;
crosses placenta; excreted in breast milk. Metabolism:
Rapidly converted to acyclovir
during first pass through intestine and liver. Elimination:
4050% in urine. Half-Life:
Assessment & Drug Effects
- Monitor kidney function in patients with kidney impairment or those receiving potentially nephrotoxic drugs.
- Monitor for S&S of hypersensitivity; if present, withhold drug and notify physician.
Patient & Family Education
- Be aware of potential adverse effects and do not discontinue drug until full course is completed.
- Note: Post-herpes pain is likely to be present for several months after completion of therapy.