Most commonly, patients experience malaise. Less commonly, patients experience inflammation or phlebitis at the infusion site, nausea, vomiting, transaminitis, and rash (including Steven-Johnson syndrome) when taken intravenously. Rotating infusion sites and decreasing the final infusion concentration to less than 10 mg/mL can help prevent inflammation/phlebitis at the infusion site.Patients also may experience nausea, vomiting, diarrhea, and headache when taken orally. Least commonly, patients experience abdominal pain, aggression/confusion, agitation, alopecia, anaphylaxis, anemia, angioedema, anorexia, ataxia, coma, disseminated intravascular coagulation (DIC), dizziness, and fatigue. In certain pediatric patients, acyclovir has been shown to decrease hemoglobin concentrations and the absolute neutrophil count.