penciclovir and Chickenpox

The current arsenal of antiviral agents available to the practitioner is expanding rapidly, such that by the time this article goes to press, new drugs may have already been added. Although the majority of approved drugs have been developed for use in only a few viral infections (eg, HIV, herpesviruses, and papillomavirus), discoveries made in the development of these drugs may lead to antiviral agents effective against other viruses. In addition, new uses for the currently available drugs are under evaluation. This review of antiviral agents discusses the treatments available for viral infections such as herpes simplex virus, varicella zoster virus, cytomegalovirus, human papillomavirus, chronic viral hepatitis, and others.

Topics: 2-Aminopurine; Acyclovir; Antiviral Agents; Chickenpox; Cytomegalovirus Infections; Famciclovir; Foscarnet; Guanine; Hepatitis B; Hepatitis C; Herpes Genitalis; Herpes Simplex; Herpesvirus 3, Human; Herpesvirus 8, Human; Humans; Papillomavirus Infections; Sarcoma, Kaposi; Skin Diseases, Viral; Valacyclovir; Valine

Topics: 2-Aminopurine; Acyclovir; Adrenal Cortex Hormones; Antiviral Agents; Chickenpox; Famciclovir; Guanine; Herpes Zoster; Humans; Immunocompromised Host; Prodrugs; Valacyclovir; Valine

Two multicenter, open-label, single-arm, two-phase studies evaluated single-dose pharmacokinetics and single- and multiple-dose safety of a pediatric oral famciclovir formulation (prodrug of penciclovir) in children aged 1 to 12 years with suspicion or evidence of herpes simplex virus (HSV) or varicella-zoster virus (VZV) infection. Pooled pharmacokinetic data were generated after single doses in 51 participants (approximately 12.5 mg/kg of body weight [BW] for children weighing < 40 kg and 500 mg for children weighing > or = 40 kg). The average systemic exposure to penciclovir was similar (6- to 12-year-olds) or slightly lower (1- to < 6-year-olds) than that in adults receiving a 500-mg dose of famciclovir (historical data). The apparent clearance of penciclovir increased with BW in a nonlinear manner, proportional to BW(0.696). An eight-step weight-based dosing regimen was developed to optimize exposure in smaller children and was used in the 7-day multiple-dose safety phases of both studies, which enrolled 100 patients with confirmed/suspected viral infections. Twenty-six of 47 (55.3%) HSV-infected patients who received famciclovir twice a day and 24 of 53 (45.3%) VZV-infected patients who received famciclovir three times a day experienced at least one adverse event. Most adverse events were gastrointestinal in nature. Exploratory analysis following 7-day famciclovir dosing regimen showed resolution of symptoms in most children with active HSV (19/21 [90.5%]) or VZV disease (49/53 [92.5%]). Famciclovir formulation (sprinkle capsules in OraSweet) was acceptable to participants/caregivers. In summary, we present a weight-adjusted dosing schedule for children that achieves systemic exposures similar to those for adults given the 500-mg dose.

Topics: 2-Aminopurine; Acyclovir; Antiviral Agents; Chickenpox; Child; Child, Preschool; Drug Administration Schedule; Drug Therapy, Combination; Famciclovir; Female; Herpes Simplex; Herpesvirus 3, Human; Humans; Infant; Male; Simplexvirus; Treatment Outcome