Drug Characteristics
  • Formulation

    Tablets: 200 mg, 400 mg, 800 mg

    Suspension: 200 mg/5ml, 400 mg/5ml

    Injection: 25 mg/ml (250mg, 500mg 1g vials)

  • Dose

    Herpes simplex: 200–400 mg orally five times a day for 5 days or (or 5 mg/kg IV 8 hourly in more serious infection) duration of treatment adjusted according to response.

    Prophylaxis of herpes simplex infections: 200–400 mg orally twice a day continuously.

    Herpes zoster: 800 mg orally five times a day for 7–10 days (or 10 mg/kg IV 8 hourly) duration of treatment adjusted according to response. Following clinical improvement IV therapy may be switched to oral therapy.

    Herpes encephalitis: 10 mg/kg IV three times a day for 7–14 days (Unlicensed 15 mg/kg IV three times a day)

    Progressive outer retinal necrosis (PORN): 10 mg/kg IV three times a day with foscarnet 90 mg/kg IV twice a day.

    Acute retinal necrosis: Aciclovir followed by oral valaciclovir

  • Side Effects

    Renal toxicity (particularly at high doses), watch patient for signs of dehydration and give additional fluids during IV administration, or high dose oral administration, neurological reactions (dizziness, confusional states, hallucinations), somnolence (usually in patients with renal impairment), skin rash, abnormal LFTs, nausea

  • Interactions

    Probenecid increases the half life and bioavailability of aciclovir, however not thought to warrant dose adjustment

  • Renal


    GFR >10: 800 mg every 8 hours

    GFR <10: 800 mg every 12 hours


    GFR 25–50: 5–10 mg/kg every 12 hours

    GFR 10–25: 5–10 mg/kg every 24 hours

    GFR <10: 2.5–5 mg/kg every 24 hours

    Caution when used in conjunction with other drugs which are renally excreted

  • Hepatic

    Use with caution in patients with serious hepatic dysfunction

  • Pregnancy


  • Other Information

    It is recommended that the state of hydration and the creatinine clearance should be evaluated before the administration of high dosages of aciclovir, especially in patients with reduced body mass.

    Ensure infusion is administered as a slow IV infusion over a minimum of 1 hour.