Valacyclovir Hydrochloride

A to Z Drug Facts

  Action Converted to acyclovir, which then inhibits viral DNA replication by interfering with viral DNA polymerase.

  Indications Treatment of herpes zoster (shingles); treatment or suppression of genital herpes; treatment of herpes labialis (cold sores).

  Contraindications Hypersensitivity or intolerance to valacyclovir, acyclovir, or any component of the formulation.

  Route/Dosage

Herpes Zoster

Adults: PO 1 g tid for 7 days (initiate therapy within 48 hr of onset of rash).

Genital Herpes

Adults: PO Initial episodes: 1 g bid for 10 days (initiate therapy within 48 to 72 hr of onset of signs and symptoms). Recurrent episodes: 500 mg bid for 3 days (initiate therapy within 24 hr of onset of signs or symptoms). Suppressive therapy: 1 g once daily. If history of recurrence up to 9 recurrences/yr, 500 mg/day may be administered.

Herpes Labialis

Adults: PO 2 g bid for 1 day approximately 12 hr apart, initiated at earliest symptoms of cold sore (eg, tingling, burning, itching).

  Interactions

Cimetidine, probenecid:

Increased acyclovir serum concentrations.

  Lab Test Interferences None well documented.

  Adverse Reactions

CNS: Headache; dizziness. GI: Nausea; vomiting; diarrhea; constipation; abdominal pain; anorexia. OTHER: Asthenia.

  Precautions

Pregnancy: Category B. Lactation: Undetermined (acyclovir is excreted in breast milk). CHILDREN: Safety and efficacy not established. Elderly: Dosage reduction may be necessary, depending on underlying renal status. Renal function impairment: Dosage reduction may be necessary; exercise caution when giving valacyclovir to patients with renal impairment or those receiving potentially nephrotoxic drugs. Immunocompromised: Valacyclovir is not indicated for use in immunocompromised patients.

  Administration/Storage

• May be taken without regard to meals.
• Store at room temperature.

  Assessment/Interventions

• Obtain patient history.
• Assess for history of present herpes zoster illness and time of rash onset. Start treatment up to 72 hr after rash onset.
• Monitor for effectiveness of treatment: Crusting and disappearance of hepatic zoster lesions; pain relief.
• Assess for history of present genital herpes illness and time of onset of signs and symptoms. Initiate treatment within 48 to 72 hr of onset of signs and symptoms.
• Monitor for effectiveness of treatment (ie, improvement in signs and symptoms).
• Assess for history of present, recurrent genital herpes illness and time of onset of signs and symptoms. Initate treatment within 24 hr of onset of signs and symptoms.
• Monitor for effectiveness of treatment (ie, improvement in signs and symptoms).

  Patient/Family Education

Herpes Zoster

• Advise patient to initiate treatment as soon as possible after diagnosis of herpes zoster and up to 72 hr after onset of zoster rash.
• Instruct patient to take medication exactly as prescribed.
• Instruct patient not to alter dose or discontinue medication without consulting health care provider.
• Instruct patient not to take any other medications, including OTC medications, without checking with health care provider first.
• Instruct patient to notify health care provider if there is no reduction in severity of lesions within 7 days.
• Inform patient to report any serious side effects to health care provider, including: syncope, dizziness, nausea, vomiting, diarrhea, headache, abdominal pain, anorexia.

Genital Herpes

• Advise patient to avoid sexual intercourse while genital herpes lesions are present.
• Tell patient that valacyclovir is a treatment not a cure.
• Advise patient to initiate therapy at first sign of symptoms of an episode.
• Instruct patient to notify health care provider if there is no reduction in severity of signs and symptoms.

Books@Ovid
Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts