Acyclovir, Zovirax IV
|Reviewed by Brenda
Hughes (Pharmacy), Dr Malcolm Battin
20 mg/kg/dose IV infusion by syringe pump over one hour.
30 to 36
All gestations >28days
- * Standard dosing has been “every 8 hours” in this group but
recent literature has suggested “every 6 hours can be used in infants 36
- 41 weeks gestation, under 28 days of age” – with monitoring for
toxicity (FBC/creatinine – see Special Considerations). Consult with
Neonatology Specialist or ID Physician before initiating “every 6 hours”
- Treat disseminated Neonatal herpes simplex virus (HSV) for 21 days
if baby has CNS involvement
- Treat Varicella zoster virus (VZV) for 7 – 10 days
- Double the dose interval for renal failure.
- Reduce dose if severe renal failure (serum creatinine greater than
- Neonatal herpes simplex infections (especially if CNS and pulmonary
- Neonatal varicella zoster infections.
- Hypersensitivity to aciclovir or valaciclovir.
- Caution in preterm infants, especially extreme immaturity.
- Caution in infants with renal, hepatic or electrolyte
abnormalities or significant hypoxia.
- Caution in infants with underlying neurological abnormalities.
- Maintain adequate hydration.
Antiviral agent which is highly active in vitro against herpes simplex (types
1 and 2) and varicella zoster viruses. Preferentially taken up by infected cells
and then phosphorylated to the active compound aciclovir triphosphate. Acts as
an inhibitor of, and substrate for, the herpes specified DNA polymerase.
Prevents further viral DNA synthesis without affecting normal cellular
processes. Toxicity to mammalian host cells is low.
Widely distributed throughout the body fluids and tissues. CSF concentrations
approximately 50% that of plasma. Low binding (9-24%) to human plasma protein.
Eliminated, mainly unchanged via the kidney, primarily by glomerular filtration.
Elevated serum concentrations may be reduced by haemodialysis.
Possible Adverse Effects
- Increases in liver-related enzymes (reversible)
- Increase in urea and creatinine – slow infusion over one hour and
adequate patient hydration may avoid this.
- Venous irritation. Inflammation and phlebitis at IV site following
- Other adverse effects: renal failure, thrombotic thrombocytopenic
purpura (TTP)/haemolytic uremic syndrome (HUS).
- Renal function. Check prior to commencing and during therapy. Use a
slow infusion rate and maintaine adequate hydration to minimise the risk
of renal dysfunction and renal crystalluria.
- Concomitant nephrotoxic drugs. Consider impact of these on renal
- CNS toxicity. More likely to occur with accumulation of aciclovir
due to reduced renal function.
- Full Blood count.
- Liver function tests.
- Monitoring for 6 hourly dose interval:
- monitor creatinine & urea daily, FBC weekly. Keep patient
hydrated and administer dose over 60 minutes.
- Resistant viral strains may emerge during long term therapy. There is NO
evidence Aciclovir will stop transmission of the virus
- Aciclovir (Zovirax®) is licensed in New Zealand for the treatment of
Herpes simplex infections in neonates