Respiratory, thoracic and mediastinal disorders

Rare: Dyspnoea

Gastrointestinal disorders

Common: Nausea, vomiting, diarrhoea and abdominal pain.

Hepato-biliary disorders

Rare: Reversible rises in bilirubin and liver related enzymes.

Very rare: Hepatitis and jaundice.

Skin and sub-cutaneous tissue disorders

Common: Skin rashes, pruritus (including photosensitivity).

Uncommon: Urticaria, accelerated diffuse hair loss .

Accelerated diffuse hair loss has been associated with a wide variety of disease processes and medicines, the relationship of the event to aciclovir therapy is uncertain.Rare: Angioedema, erythema multiforme, Stevens Johnson syndrome, toxic epidermal necrolysis.

Renal and urinary disorders

Rare: Increases in blood urea and creatinine; renal impairment, usually during intravenous therapy, which is usually reversible and responds to hydration and/or dosage reduction but may progress to acute renal failure in patients with predisposing factors.

Very rare: Acute renal failure, renal pain

Renal pain may be associated with renal failure.

General disorders

Common: Fatigue, fever.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.

4.9 Overdose
Symptoms and signs

Aciclovir is only partly absorbed in the gastrointestinal tract.

Patients have ingested overdoses of up to 20 g aciclovir 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 (eg headache and confusion).

Overdosage of i.v. aciclovir 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 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.

5. Pharmacological properties
5.1 Pharmacodynamic properties
Pharmacotherapeutic group - ATC code: J05A B

Aciclovir is an antiviral agent which is highly active in vitro against herpes simplex virus (HSV) types I and II and varicella zoster virus. Toxicity to mammalian host cells is low.

Aciclovir is phosphorylated after entry into herpes infected cells to the active compound aciclovir triphosphate. The first step in this process is dependant on the presence of the HSV-coded thymidine kinase. Aciclovir triphosphate acts as an inhibitor of, and substrate for, the herpes-specified DNA polymerase, preventing further viral DNA synthesis without aff