Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Topical antiviral agent, ATC code: D06BB06 
Mechanism of action
Penciclovir has demonstrated in vivo and in vitro activity against herpes simplex viruses (types 1 and 2) and varicella zoster virus. In virus-infected cells Penciclovir is rapidly and efficiently converted into a triphosphate (mediated via virus-induced thymidine kinase).Penciclovir triphosphate persists in infected cells for more than 12 hours where it inhibits replication of viral DNA and has a half-life of 9, 10 and 20 hours in cells infected with varicella zoster virus, herpes simplex virus type 1 and herpes simplex virus type 2 respectively. In uninfected cells treated with Penciclovir, concentrations of Penciclovir triphosphate are only barely detectable. Accordingly, uninfected cells are unlikely to be affected by therapeutic concentrations of Penciclovir.
Clinical efficacy and safety
In clinical studies, Penciclovir treated patients healed 30% faster than placebo (up to one day earlier), pain resolution was 25-30% faster (median improvement of up to one day) and infectivity resolved up to 40% faster (one day earlier) than placebo.

Pharmacokinetic Properties

5.2 Pharmacokinetic properties
General characteristics
Following application of Penciclovir in a human volunteer study at a daily dose of 180mg Penciclovir (approximately 67 times the proposed daily clinical dose), to occluded and abraded skin for 4 days, Penciclovir was not quantifiable in plasma and urine.