Article: PDF OnlyTreatment of Acyclovir-Resistant Herpes Simplex Virus Infections in Patients with AIDSSafrin, SharonAuthor Information Department of Medicine, University of California at San Francisco, and San Francisco General Hospital, San Francisco, California Journal of Acquired Immune Deficiency Syndromes: Volume 5 - Issue - p S29-32 Free Abstract Resistance to acyclovir in vitro in herpes simplex virus (HSV) isolates has been associated with failure of acyclovir therapy in immunosuppressed patients, and the frequency of reports of clinical resistance in patients with human immunodeficiency virus (HIV) infection is increasing. The primary mechanism of clinical resistance is mutation, producing deficiency in the virus-specified thy-midine kinase. A number of case reports and patient series have suggested the efficacy of foscarnet in the treatment of acyclovir-resistant HSV infection in HIV-infected patients. In a recent AIDS Clinical Trials Group study comparing the efficacy of vidarabine and foscarnet in this indication, foscarnet therapy was found to be associated with statistically significant reductions in time to complete healing of lesions, cessation of viral shedding, and 50% reduction in pain, and all patients randomized to receive foscarnet had complete re-epithelialization of lesions. The majority of initial recurrences of herpetic lesions in patients in this study were susceptible to acyclovir, however, all patients ultimately experienced a recurrence due to acyclovir-resistant HSV. A trial comparing acyclovir suppression, foscarnet maintenance therapy, and no chronic antiviral therapy after successful initial treatment of acyclovir-resistant HSV infection would be useful in defining the optimal management of recurrent disease. © Lippincott-Raven Publishers.