SN instructed patient / caregiver that valacyclovir is an antiviral drug used in the management of herpes simplex, herpes zoster, and herpes B. Common adverse drug reactions are the same as for valacyclovir and include: nausea, vomiting, diarrhea and headache. Infrequent adverse effects may include: agitation, vertigo, confusion, dizziness, edema, arthralgia, sore throat, constipation, abdominal pain, rash, weakness and/or renal impairment. Rare adverse effects include: coma, seizures, neutropenia, leukopenia, tremor, ataxia, encephalopathy, psychotic symptoms, crystalluria, anorexia, fatigue, hepatitis, Stevens–Johnson syndrome, toxic epidermal necrolysis and/or anaphylaxis.