Drug Characteristics
  • Formulation

    Tablet: 250 mg, 500 mg

  • Dose

    Herpes simplex:

    500 mg orally twice a day for 5 days (10 days if severe)

    Suppression of herpes simplex:

    500 mg orally twice a day continuously.

    Herpes zoster:

    1g orally three times a day for 7 days

    Valaciclovir is the valine ester pro-drug of aciclovir. Higher oral bioavailability than aciclovir, therefore requires less frequent dosing. May be useful in patients with herpes simplex infections unresponsive to oral aciclovir, where aciclovir resistance is unproven

  • Side Effects

    Gastrointestinal disturbances (nausea, vomiting, diarrhoea, abdominal pain); headache; rash; neurological reactions (dizziness, hallucinations, confusion, drowsiness)

  • Interactions

    Care with nephrotoxic drugs e.g. aminoglycosides, amphotericin, cidofovir, and foscarnet

    Probenecid reduces renal excretion

  • Renal

    Dose in renal impairment GFR (ml/min)

    30–50: Dose as in normal renal function

    15–30: Herpes simplex dose as in normal renal function.

    Herpes zoster 1g every 12 hours

    <15: Herpes simplex 500 mg daily

    Herpes zoster: 1g every 24 hours

    Herpes simplex suppression 500 mg daily

  • Hepatic

    Clinical experience limited

    Caution with higher doses in patients with hepatic impairment

  • Pregnancy


  • Other Information