Comparison of new topical treatments for herpes labialis: efficacy of penciclovir cream, acyclovir cream, and n-docosanol cream against experimental cutaneous herpes simplex virus type 1 infection

Arch Dermatol. 2001 Sep;137(9):1153-8. doi: 10.1001/archderm.137.9.1153.


Background: There are 3 new topical treatments for herpes labialis that have either been approved by the US Food and Drug Administration (penciclovir cream [Denavir] and n-docosanol cream [Abreva]) or recently undergone extensive clinical evaluation (acyclovir cream). The relative efficacy of these products is unknown.

Objective: To compare the efficacy of penciclovir cream, acyclovir cream, n-docosanol cream, and acyclovir ointment in an experimental animal model of cutaneous herpes simplex virus type 1 (HSV-1) disease.

Design: The backs of guinea pigs were infected with HSV-1 using a vaccination instrument. Active treatments and corresponding vehicle controls were applied for 3 to 5 days beginning 24 hours after inoculation.

Main outcome measures: After completion of treatment, the animals were killed and the severity of the infection assessed from the number of lesions, the total lesion area, and the lesion virus titer.

Results: Penciclovir cream effected modest reductions in lesion number (19%), area (38%), and virus titer (88%) compared with its vehicle control, and each of these differences was significantly greater (P<.05) than the reductions effected by acyclovir ointment (0%, 21%, and 75%, respectively). The acyclovir cream effect (reductions of 4%, 28%, and 77%, respectively) was less than that of penciclovir cream, and this difference was confirmed by 2 additional head-to-head experiments. Two experiments with n-docosanol cream failed to show statistically significant differences by any parameter between n-docasonol cream and vehicle control-treated sites or between n-docosanol and untreated infection sites.

Conclusions: In this model, the efficacy of penciclovir cream was greater than acyclovir cream, acyclovir cream was greater than or equal to acyclovir ointment, and acyclovir ointment was greater than n-docosanol cream. Since our model was designed to evaluate compounds that function primarily through antiviral activity, the negative findings with n-docosanol in these studies do not exclude that it might work clinically through other mechanisms.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyclovir / administration & dosage*
  • Acyclovir / adverse effects
  • Acyclovir / analogs & derivatives*
  • Administration, Topical
  • Animals
  • Disease Models, Animal
  • Fatty Alcohols / administration & dosage*
  • Fatty Alcohols / adverse effects
  • Female
  • Guanine
  • Guinea Pigs
  • Herpes Labialis / drug therapy*
  • Herpesvirus 1, Human / drug effects*
  • Humans
  • Treatment Outcome


  • Fatty Alcohols
  • penciclovir
  • Guanine
  • docosanol
  • Acyclovir