Aciclovir IV

CLINICAL USE

Antiviral agent:Herpes simplex and herpes zoster infection

DOSE IN NORMAL RENAL FUNCTION

Herpes simplex treatment: normal or immunocompromised 5 mg/kg every 8 hours

Recurrent varicella zoster infection: normal immune status 5 mg/kg every 8 hours

Primary and recurrent varicella zoster infection: immunocompromised 10 mg/kg every 8 hours

Herpes simplex encephalitis: normal or immunocompromised 10 mg/kg every 8 hours

PHARMACOKINETICS

Molecular weight :225.2

%Protein binding :9–33

%Excreted unchanged in urine : 40–70

Volume of distribution (L/kg) :0.7

half-life – normal/ESRD (hrs) :2.9/19.5 (dialysis: 5.7)

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

25–50 5–10 mg/kg every 12 hours10–25 5–10 mg/kg every 24 hours (some units use 3.5–7 mg/kg every 24 hours)

<10 : 2.5–5 mg/kg every 24 hours

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD :Not dialysed. Dose as in GFR <10 mL/min

HD :Dialysed. Dose as in GFR <10 mL/min

HDF/high flux :Dialysed. Dose as in GFR <10 mL/min

CAV/VVHD :Dialysed. Dose as in GFR=10–25 mL/min

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

Ciclosporin: reports of increased and decreased ciclosporin levels. Some editors report no experience of interaction locally; possibly increased risk of nephrotoxicity

Higher plasma levels of aciclovir and mycophenolate mofetil with concomitant administrationTacrolimus: possibly increased risk of nephrotoxicity

ADMINISTRATION

Reconstition

Sodium chloride 0.9% or water for injection; 10 mL to each 250 mg vial; 20 mL to 500 mg vial (Resulting solution contains 25 mg/mL)

Route

Rate of Administration

1 hour; can worsen renal impairment if injected too rapidly!

Comments

Reconstituted solution may be further diluted to concentrations not greater than 5 mg/mL

Use 100 mL infusion bags for doses of 250–500 mg; use 2 × 100 mL bags for 500–1000 mg

Compatible with sodium chloride 0.9% and glucose 5%

DO NOT REFRIGERATE

Do not use turbid or crystal-containing solutions

Reconstituted solution very alkaline (pH 11)

OTHER INFORMATION

Aciclovir clearance in CAVHD is approximately equivalent to urea clearance, i.e. lower clearance than in intermittent haemodialysis

Monitor aciclovir levels in critically ill patients. Reports of neurological toxicity at maximum recommended doses

Renal impairment developing during treatment with aciclovir usually responds rapidly to rehydration of the patient, and/or dosage reduction or withdrawal of the drug. Adequate hydration of the patient should be maintained

Plasma aciclovir concentration is reduced by 60% during haemodialysis

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