General Info:

A cold sore, also known as a fever blister, is caused by a virus called herpes simplex type 1 (HSV1), which is easily passed from person to person. It can be transmitted through many types of contact, including a kiss, sharing eating utensils, or close skin contact. Unfortunately, once you have the cold sore virus, it stays in your body forever.

Denavir (penciclovir cream) is an antiviral medicine for cold sores that is available by a prescription from your physician or dentist. It penetrates the area to block the virus that causes cold sores. Denavir works best when it's applied during the early signs of a cold sore - at the tingle or when a blister appears. If you are a regular sufferer, ask your physician or dentist if Denavir might be right for you.

Denavir should be applied to cold sore lesions every 2 hours while awake for a period of four days, unless otherwise directed by your doctor.