Acyclovir sodium is the drug of choice for the treatment of herpes simplex encephalitis. We treated an immunocompetent patient with a ten-day course of intravenous acyclovir sodium at the recommended dosage of 10 mg/kg every eight hours for clinically apparent herpes simplex encephalitis. After marked improvement, his condition deteriorated four days after completing acyclovir therapy. A subsequent brain biopsy specimen disclosed acyclovir-sensitive herpes simplex virus type 1. A longer duration of acyclovir therapy (14 to 21 days) should be considered for treating herpes simplex encephalitis.
Kevan E. VanLandingham, H. Blair Marsteller, Gary W. Ross, Frederick G. Hayden. Relapse of Herpes Simplex Encephalitis After Conventional Acyclovir Therapy. JAMA. 1988;259(7):1051–1053. doi:10.1001/jama.1988.03720070051034