Herpes simplex virus in immunocompromised patients: growing evidence of drug resistance.

Antiviral drugs have proven effective in treatment of herpesvirus infections and in prevention of reactivation of latent virus. The prototype drug is acyclovir. Herpes simplex virus (HSV) is susceptible to acyclovir. There is increasing evidence in immunocompromised patients of acyclovir-resistant HSV causing clinical disease. Mechanisms of HSV resistance to acyclovir are known. These findings have implications for the future development and clinical use of antiviral drugs.