FAMCICLOVIR - A REVIEW OF ITS PHARMACOLOGICAL PROPERTIES AND THERAPEUTIC EFFICACY IN HERPESVIRUS INFECTIONS

Famciclovir a synthetic acyclic guanine derivative, is a prodrug which , after oral administration, is rapidly metabolised to the highly bioa vailable antiviral compound penciclovir. Penciclovir is active in vitr o against the herpesviruses herpes simplex virus (HSV)-1, HSV-2 and va ricella tester virus (VZV). Famciclovir is an effective treatment of i mmunocompetent patients with acute herpes tester (shingles) caused by VZV. Comparative studies have demonstrated that famciclovir has therap eutic efficacy similar to that of oral aciclovir (acyclovir) in attenu ating the acute signs and symptoms of infection (including pain during the acute phase of infection). In a placebo-controlled study, famcicl ovir significantly reduced the duration of postherpetic neuralgia; thi s effect was more pronounced (almost a 3-fold reduction) in patients a ged greater than or equal to 50 years. In immunocompetent patients wit h recurrent genital herpes infection, suppressive treatment with oral famciclovir effectively prolonged the time to recurrence of symptomati c episodes of infection compared with placebo. In addition, famciclovi r significantly reduced the duration of viral shedding, accelerated he aling of genital herpes lesions and reduced the duration of symptoms. Famciclovir is reported to be the first antiviral agent to significant ly reduce symptoms associated with multiple genital herpes lesions. Fa mciclovir is a well-tolerated drug with a tolerability profile similar to that of placebo and aciclovir. Thus, famciclovir is now establishe d as an effective treatment of immunocompetent patients with herpes te ster or genital herpes infection, particularly as famciclovir is admin istered in a convenient dosage regimen that may improve compliance com pared with aciclovir.