Denavir ® and Zovirax ® : Prescription medications used in the treatment of cold sores (oral herpes / fever blisters).
FDA approved prescription medications for the treatment of fever blisters.
Denavir ® cream 1% and Zovirax ® cream 5% are the only prescription medications that have been approved by the FDA for the treatment of cold sores.
Denavir ® (penciclovir) received its FDA approval in 1996, Zovirax ® (acyclovir) received its approval in the treatment of cold sores in late 2002. ( Denavir is a registered trademark of Novartis Consumer Health, Inc. Zovirax is a registered trademark of GlaxoSmithKline. )
How they work.
The mode of action associated with these medications is that they have the capability to interfere with the herpes simplex virus' ability to replicate (produce more virus particles). Since these products are true antiviral compounds, most dentists would probably consider them to be the treatment modality of choice for the treatment of cold sores.
The idea associated with the use of an antiviral medication is that if it is applied early enough (i.e., the Tingle stage) it can help to limit both the severity and duration of a cold sore by way of limiting the total number of virus particles that are involved.
These are treatments, not a cure.
This is not to imply that these drugs provide a cure for cold sores nor are these medications considered preventive in nature. Their intended use is simply to help in managing and limiting the severity of current cold sore outbreaks. Even after the use of one of these products, and after the cold sore has healed, the herpes virus still resides latently within the person's body. The person still retains their potential for future cold sore outbreaks.
It is important for a person to understand that even with the use of one of these antiviral creams herpes virus particles are still present in their cold sore lesion throughout each of its stages of formation. For this reason a cold sore treated with an antiviral medication should still be considered to be contagious.
Which is best, Devavir ® cream or Zovirax ® cream?
We think that the answer to this question is best answered by your health care professional. Having said that, three of the sources we have used as references for this page ( Femiano 2001, Lin 2002, McKeough 2001) have each studied the head-to-head effectiveness of acyclovir cream (the compound found in Zovirax) and penciclovir cream (the compound found in Denavir) in the treatment of cold sores. The conclusions drawn by all three of these studies suggest that penciclovir cream (Denavir) is the more effective medication.
As a side note, please keep in mind:
All prescription medications should only be used under the direction and supervision of a health care professional.
All stages of cold sore formation should be considered to be contagious. So to avoid spreading the herpes virus (either to other people or other parts of your own body), after applying any medication or treatment to cold sores you should always wash your hands.
Denavir cream 1% (penciclovir)
Denavir cream was the first antiviral medication to be granted FDA approval for use in the treatment of cold sores (1996). The instructions for Denavir cream state that it should be applied repeatedly throughout the day every 2 waking hours (roughly 9 times a day) for 4 days on those external areas of the lips or face where the cold sore is developing (Denavir cream is not intended for internal use). Application of Denavir should be started as soon as it's sensed that a cold sore has begun to form (i.e., the Tingle stage).
Zovirax cream 5% (acyclovir)
Zovirax cream only received FDA approval for use in the treatment of cold sores in late 2002, although other formulations of this medication have been used in the treatment of herpes for many years (including an "off-label" use in the treatment of cold sores in the years prior to 2002). The use of Zovirax cream is similar in nature as with Denavir cream, however the manufacturer claims a more convenient topical dosing schedule.
The instructions for Zovirax cream state that its use should be initiated as soon it is sensed that a cold sore has begun to form (i.e., the Tingle stage). The cream is applied to those external areas of the lips or face where the cold sore is developing (Zovirax cream is not intended for internal use), 5 times a day for 4 days.