Acyclovir (Zovirax®) vs Docosanol (Abreva®)

Based on "Antibiotic and Chemotherapy"
written by Roger G. Finch

Difference between topical Acyclovir and Docosanol

  • Docosanol (Abreva®) cream is an acceptable OTC alternative to prescription topical acyclovir (Zovirax®). The only advantage of docosanol is that it is available without a prescription.
  • In practice, docosanol cream is hardly any effective than an excipient in treating cold sores4.
  • In experimental research5 acyclovir demonstrated more potent antiviral activity than n-docosanol.


Acyclovir Docosanol
• Zovirax®
• Abreva®
Zovirax cream 5% Abreva cream
Drug class
• Synthetic nucleoside analogue active against herpes simplex virus (HSV) • 22-carbon saturated aliphatic alcohol
Dose formulations
• Topical cream 5% • Topical cream 10%
FDA-approved indications
• Treatment of recurrent herpes labialis (cold sores) in immunocompetent adults and adolescents 12 years of age and older
•Treatment of recurrent herpes labialis (cold sores) in immunocompetent adults and adolescents 12 years of age and older • Treatment of recurrent herpes labialis (perioral herpes, cold sores, fever blisters).
Dosage regimen
• 5 times per day for 4 days. • 5 times per day until healed (maximum 10 days)
Mechanism of action
• Acyclovir is an antiviral drug which is highly active against herpes viruses.
• Acyclovir interferes with viral DNA polymerase and inhibits the replication of virus.
• Docosanol is not a true antiviral medication because this agent has no direct virucidal activity by itself.
• The antiviral effects of docosanol are due to its inhibition of the viral entry into the cell 3.
• Hypersensitivity to acyclovir, valacyclovir or any component of the formulation • Hypersensitivity to docosanol or component of the formulation
Side effects
• Burning, stinging or other local skin reactions at the application site
Pregnancy category
• B • Not available
Therapeutic effect
• Reduces the duration of cold sores episode by one-half day1.
• Reduces the duration of cold sores episode by one-half day1.
• No effects on prevention of progression of herpes lesions.

Further reading


  • 1. Prescribing Information for Zovirax® (Acyclovir) PDF
  • 2. Prescribing Information for Abreva® (Docosanol) PDF
  • 3. Pope LE, Marcelletti JF, Katz LR, Lin JY, Katz DH, Parish ML, Spear PG. The anti-herpes simplex virus activity of n-docosanol includes inhibition of the viral entry process.Antiviral Res. 1998 Dec;40(1-2):85-94.
  • 4. Docosanol: new drug. Herpes labialis: barely more effective than an excipient. Prescrire Int. 2009 Jun;18(101):106-7. PubMed
  • 5. McKeough MB, Spruance SL.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.

Published: September 20, 2018
Last reviewed: September 20, 2018


Interesting facts
  • Topical treatments for cold sores are less effective than oral antiviral medications.
  • Topical medications decrease healing time and pain duration by less than a day, but require multiple daily applications.
More Comparisons
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