Acyclovir in Preventing Herpes Simplex Virus Infection in Patients With Neutropenia

Inclusion Criteria: * Be 18 years of age or older. * Receiving treatment in inpatient oncology services at Wake Forest University Baptist Medical Center * Receiving chemotherapy or have received chemotherapy within the past 2 weeks * Seropositive herpes simplex virus (HSV)-1 or HSV-2 immunoglobulin antibody assay * Creatinine clearance ≥ 50 mL/min * Intravenous acyclovir sodium therapy is deemed necessary by the physician based upon clinical judgement (i.e., mucositis, vomiting, decreased GI absorption) Exclusion Criteria: * Pregnant or nursing * Hypersensitivity to acyclovir sodium * High tumor burden (i.e., WBC \> 50,000/mm\^3 at admission) * Neutropenic, defined as one of the following: * ANC \< 500/mm\^3 * ANC \< 1,000/mm\^3 with a predicted decrease to 500/mm\^3 * Active HSV infection, as evidenced by any of the following: * Positive HSV cultures * Oral lesions * Receiving 5 mg/kg acyclovir sodium every 8 hours