In a 2008 review published in the "Archives of Internal Medicine," Northeastern Ohio University internist Dr. Christina Cernik explains that 95 percent of cold sores occur on lips or other parts of the face. Cold sores inside the mouth are uncommon and usually occur only during the first outbreak of cold sores. Common sites inside the mouth include the roof of the mouth, the back of the throat, the gums, the lining of the cheeks and, occasionally, the tongue. The treatment for a cold sore inside the mouth consists of antiviral drugs.
Indications
Since most cold sores heal without treatment, according to Cernik, antiviral drugs are typically reserved for patients with moderate or severe symptoms and those who suffer from recurrent outbreaks. Cold sores inside the mouth meet the criteria because they are usually accompanied by extensive lesions outside the mouth, as well as systemic symptoms such as fever, headache and malaise. In addition, cold sores inside the mouth sometimes interfere with eating or drinking, especially in young children who are susceptible to dehydration.
Mechanism of Action
Antiviral drugs used to treat cold sores also treat infections caused by other viruses in the herpes family, such as chicken pox, shingles and genital herpes. In the 2008 edition of "Basic and Clinical Pharmacology," Dr. Sharon Safrin of the University of California San Francisco explains that the drugs work by substituting a nonsense molecule for the nucleic acid, guanosine, that the virus requires to reproduce. The drugs have limited effects on healthy cells because the drug requires a viral enzyme, thymidine kinase, to become active.
Dosing and Administration
Cold sores can be treated with topical or oral medications. Cold sores inside the mouth require oral medications. Choices include acyclovir, valacyclovir and famciclovir; all three are available as generics. Acyclovir is the only drug that is approved for children younger than 1, but it requires five daily doses. Patients take valacyclovir and famciclovir twice a day. Valacyclovir is suitable for patients 1 and up. Famciclovir is only approved for adults and children over 13.
Safety
Acyclovir, valacyclovir and famciclovir are generally well-tolerated, according to Safrin. About 10 percent of patients report side effects such as headaches, nausea, vomiting or diarrhea. The Food and Drug Administration designates all of the drugs as "pregnancy category B" because they have not been specifically tested in pregnant women. However, pregnant animals do not exhibit increased rates of birth defects. In addition, Glaxo Smith Kline reports that a five year study of pregnant women who took acyclovir during the first trimester found that the incidence of birth defects did not differ from the general population.
Effectiveness
Oral antiviral drugs reduce the severity and duration of cold sores, especially when they are taken within 48 hours of symptom onset, according to Cernik. They are most effective during the first outbreak of cold sores when they reduce the healing time from an average of nine days to about four days. In recurrent outbreaks, they may reduce healing time by only one day, although the duration of recurrent outbreaks is generally less than during first outbreaks.
Supportive Care
Oral antiviral drugs do not treat systemic symptoms of cold sores such as headache or fever, nor do they treat local pain or itching caused by the lesions themselves. MayoClinic.com recommends over-the-counter acetaminophen or ibuprofen for systemic symptoms. For local symptoms, MayoClinic.com recommends over-the-counter topical anesthetics such as lidocaine or benzocaine. Good oral hygiene such as toothbrushing, flossing and using antiseptic mouthwash helps keep the cold sores inside the mouth clean and reduces the risk of secondary bacterial infections.
References
- "Archives of Internal Medicine"; The Treatment of Herpes Simplex Infections; C. Cernik et al.; 2008
- "Basic and Clinical Pharmacology, 11th Edition"; B.G. Katzung et al.; 2008
- Academy of General Dentistry: What Are Cold Sores?
- MayoClinic.com: Cold Sore Treatments and Drugs
