Antiviral drug
Primary disease: Topical treatment has low efficacy; 5% ointment is applied locally 6 times a day for 10 days. This is useful if started early and in mild cases. Late and more severe cases should receive oral therapy (1 g/day in 5 divided doses or 400 mg TDS for 10 days) in addition to local therapy. Both local and oral therapies afford symptomatic relief and rapid healing of lesions, but do not prevent recurrences