Tablet, 200 mg, 400 mg
Powder for injection, 500 mg in vial

General information

Aciclovir, which is derived from guanine, is a synthetic purine nucleoside analogue with antiviral properties. It acts against herpesviruses by disrupting DNA synthesis and inhibiting viral replication. However, in immunocompromised patients, alpha-herpesviruses are often resistant to aciclovir.

Absorption from the gastrointestinal tract is variable and incomplete. Aciclovir is widely distributed in tissues and body fluids, including the cerebrospinal fluid. It has a plasma half-life of 3 hours and is excreted in the urine primarily unchanged.

Clinical information

Uses

• Treatment of herpes simplex infections in newborn infants, immunocompromised patients and patients with atopic eczema.

• Treatment of severe zoster infections in elderly or immunocompromised patients.

• Treatment of chickenpox in immunocompromised patients.

• Prevention of recurrent herpes simplex infections.

Dosage and administration

Intravenous infusions should be administered slowly over a period of 1 hour to avoid acute impairment of renal function.

All doses are suitable for adults and children over 2 years.

Herpes simplex:

Acute disease: 200 mg orally five times daily for 7-10 days.

Immunocompromised patients and patients with atopic eczema: 10 mg/kg i.v. three times daily for 7-10 days.

Newborn infants: 5 mg/kg i.v. three times daily for 7-10 days.

To prevent recurrence, 400 mg may be given orally twice daily for up to 1-2 years. Dosages as low as 200 mg daily have also been used.

Reactivated zoster (shingles) and chickenpox in immunocompromised patients:

Immunocompromised patients: 10 mg/ kg i.v. three times daily for 5-7 days. Elderly patients, in whom there is a risk of persistent postzoster neuralgia, respond to oral administration of 800 mg five times daily for 5-7 days.

Contraindications

Known hypersensitivity to purine nucleoside analogues.

Precautions

A high fluid intake reduces the risk of acute renal impairment.

Use in pregnancy

Safe use in pregnancy has not been established. Aciclovir should be used only when the need of the mother outweighs the risk of harm to the fetus.

Adverse effects

Reversible skin rashes, headache, nausea and vomiting occasionally occur after oral administration.

Serious adverse reactions are rare. Confusion, seizures and hallucinations have been reported after parenteral administration.

Transient renal impairment may occur during intravenous therapy, possibly as a result of crystallization in the renal tubules. This usually responds rapidly to dosage reduction or withdrawal of the drug. Acute renal failure has responded to haemodialysis.

Overdosage

Since aciclovir is incompletely absorbed from the gastrointestinal tract, oral overdosage is unlikely to have serious effects. Blood concentrations can be lowered by haemodialysis.

Storage

Tablets should be stored in well-closed containers below 25 °C. Powder for injection should be stored at 2-8 °C. After reconstitution the solution is stable for up to 12 hours at 20 °C.