famciclovir, an antiviral drug. ▪ INDICATIONS: It is prescribed in the treatment of acute herpes zoster and recurrent genital herpes. ▪ CONTRAINDICATIONS: It should not be given to patients with kidney disease or an allergy to famciclovir. The safety of the drug in children or in women who are pregnant or breastfeeding has not been established. ▪ ADVERSE EFFECTS: The side effects most often reported include fatigue, fever, pain, chills, headache, dizziness, nausea, diarrhea, vomiting, and constipation.