Pharmacological classification & ATC Classification: J05AB01 - aciclovir; Belongs to the class of nucleosides and nucleotides excluding reverse transcriptase inhibitors. Used in the systemic treatment of viral infections.
Pharmacology: Activity against HSV types I and II and varicella-zoster virus is due to intracellular conversion of aciclovir to the monophosphate by viral thymidine kinase with subsequent conversion to the diphosphate and active triphosphate by cellular enzymes. This active form inhibits viral DNA synthesis and replication by interfering with viral DNA polymerase enzyme and being incorporated into viral DNA. Absorption: 15-30% is absorbed from the GI tract (oral), slightly absorbed from the skin (topical), absorbed from the eye (ophthalmic). Distribution: CSF (50% of conc is similar to those in plasma); crosses the placenta and enters breast milk (concentrations 3 times higher than in maternal serum). Protein-binding: 9-33%. Excretion: Via kidney by glomerular filtration and tubular secretion (14% as unchanged), via faeces (2%); elimination half-life: 2-3 hr (normal renal function), 19.5% (anuric patients), 5-7% (haemodialysis patients).
Indications: Aciclovir indicated in:
Mucocutaneous herpes simplex in immunocompromised patients
Herpes simplex encephalitis
Genital herpes
Neonatal herpes simplex virus infections
Herpes zoster in immunocompromised patients
Dosage & administration: Intravenous Mucocutaneous herpes simplex in immunocompromised patients
Adult : 5 mg/kg every 8 hr for 7 days. Dose to be given as IV infusion over 1 hr.
Child : 10 mg/kg every 8 hr for 7 days.
Renal impairment: Peritoneal dialysis: Half the usual dose once daily. Haemodialysis: Half the usual dose every 24 hr and an additional half-dose after haemodialysis.
