Valtrex can take effect within two or three days. Believe it or not, the over
heartburn medicine cimetidine (which you probably know as Tagamet) can also help lessen the pain and intensity of the rash. Take 200 mg three times a day with meals, plus 400 mg at bedtime.
None of these drugs are perfect solutions. Antiviral medications are burdened by potential side effects like nausea, headache, vomiting, dizziness, and abdominal pain.