Symptoms: Aciclovir is only partly absorbed in the gastrointestinal tract. Patients have ingested overdoses of up to aciclovir 20 g on a single occasion, usually without toxic effects. Accidental, repeated overdoses of oral aciclovir over several days have been associated with gastrointestinal effects (eg, nausea and vomiting) and neurological effects (headache and confusion).
Overdosage of aciclovir IV has resulted in elevations of serum creatinine, blood urea nitrogen and subsequent renal failure. Neurological effects including confusion, hallucinations, agitation, seizures and coma have been described in association with IV overdosage.
Treatment: Patients should be observed closely for signs of toxicity. Haemodialysis significantly enhances the removal of aciclovir from the blood and may therefore be considered a management option in the event of symptomatic overdose.