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Cold Sores Information - Fever Blisters & Cold Sores

Cold Sores Treatments


Updated May 30, 2014

There are several medications available to treat cold sores. Some are used topically and others are taken orally. Cold sores are best treated as early as possible. Starting a medication when prodromal symptoms such as burning, tingling, or redness start gives the best chance of keeping the cold sores from developing or shortening their course.

Cold Sore Treatment and FDA Approval

There are several antiviral medications that are used to treat herpes infections. The FDA approves these medications for the specific type of infections they treat. The FDA has approved the use of certain drugs for cold sores, but some antiviral drugs that are not specifically FDA approved for cold sores have been shown in clinical studies to be effective. Receiving a prescription for an off-label use of one of these drugs may still be effective. The decision to use a medication that is prescribed off-label should be made based on current data and discussed thoroughly with a health-care provider.

Cold Sore Treatment Effects

Antiviral drugs can have several effects on oral herpes simplex virus infections. Examples of the effects of antiviral medications on cold sores include:
  • Decrease the time it takes for cold sores to heal
  • Reduce symptoms - especially pain
  • Prevent lesions from occurring if taken soon enough
  • Reduce the number of lesions developed if taken soon enough
  • Reduce the size of lesions developed if taken soon enough
  • Reduce the amount of viral shedding

Cold Sore Treatment - First Outbreak

The first outbreak of any herpes simplex infection is usually worse than recurrent infections. A first outbreak of oral herpes should be treated with oral medications, while recurrences can be treated with topical medications.

Cold Sore Treatment - Topical Denavir

Denavir (Penciclovir 1% cream) is FDA-approved for recurrent cold sores. Starting treatment within one hour of an outbreak can reduce the time to healing by two days as well as reducing symptoms. Denavir can also decrease the duration of viral shedding. The earlier Denavir is started the better the benefits, but improvement is often still possible when treatment is started even after vesicles develop.

Cold Sore Treatment - Acyclovir

Zovirax (Acyclovir 5% cream) is also FDA approved for the treatment of recurrent cold sores. In studies, frequent application of the cream reduced the time to healing by about half a day. Oral acyclovir given five times a day for primary gingivostomatitis in children can substantially reduce the duration of fever, eating and drinking difficulties, and viral shedding. Using low dose oral acyclovir for cold sores can shorten the duration of symptoms, but higher doses may be needed to reduce pain.

Cold Sore Treatment - Famciclovir

Famvir (Famciclovir) is approved by the FDA for treatment of cold sores. If started at the first sign of symptoms, taking a single high dose of Famvir can shorten the herpes infection by two days.

Cold Sore Treatment - Valacyclovir

Valtrex (Valacyclovir) is approved by the FDA to treat cold sores. If started at the first sign of symptoms, taking Valtrex twice a day for one day can shorten the duration of herpes infection.

Cold Sore Treatment - Suppression Therapy

Suppression therapy, taking medication every day to prevent outbreaks, is not yet FDA-approved. Studies have shown that people who have more than six recurrences or more per year can benefit from taking daily doses of acyclovir, Famvir, or Valtrex to reduce the number of recurrences and decrease viral shedding.


CDC. "Sexually Transmitted Diseases Treatment Guidelines, 2006." Morbidity and Mortality Weekly Report. 55(2006): 16-20.

Habif, Thomas. "Warts, Herpes Simplex, and Other Viral Infections" Clinical Dermatology, 4th Edition. Ed. Thomas Habif, MD. New York: Mosby, 2004. 381-388.

Spotswood Spruance, MD, et al. "Single-dose, patient-initiated famciclovir: A randomized, double-blind, placebo-controlled trial for episodic treatment of herpes labialis". Journal of the American Academy of Dermatology. 55. 2006: 47-53.

Spotswood Spruance, MD et al. "High-dose, short-duration, early valacyclovir therapy for episodic treatment of cold sores: Results of two randomized, placebo-controlled, multicenter studies". Antimicrobial Agents and Chemotherapy. 2003: 1072-80.

Yeung-Yue, Kimberly. "Herpes simplex viruses 1 and 2." Dermatologic Clinics 20(2002): 1-21.

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