Cold sores and canker sores are both conditions of the mouth that affect millions of Americans.1 Though the two conditions are often mistaken for one another, they are two entirely different ailments.

Cold Sores

Cold sores, also called fever blisters, are small blisters that appear primarily on the lips, face, and occasionally on the inside of the mouth.1 The blisters tend to itch and burn, and are especially painful when ruptured. Cold sores are caused by the herpes simplex virus (HSV-1 or HSV-2), and are highly contagious. They can take up to two weeks to heal completely, and are most commonly spread by kissing or by sharing food or drinks with an infected person.

Not all infected people develop cold sores, but once a person is infected the herpes virus remains in the body for life.1 The virus usually lies dormant in nerve cells, but once triggered by sunlight, fever, stress, (or other factors) it may surface again as an active infection at or near the site of the original outbreak.1 The herpes virus only replicates during an outbreak, with viral replication peaking 8 to 12 hours following the first “tingling” symptoms of the cold sore.

After the outbreak has passed, the virus retreats back into the nerves, waiting to strike again. The virus’ ability to lie dormant makes it difficult to treat effectively ( Even though there is not a cure for cold sore outbreaks, medications like Sitavig® (acyclovir), 50mg Muco-Adhesive Buccal Tablet can help reduce their frequency and limit their duration. Only Sitavig has been shown in a clinical study to delay the recurrence of cold sores.

Canker Sores

In contrast, canker sores are uncomfortable ulcers or open sores that grow on the tongue, inside the mouth or on the inside of the throat.1 Unlike cold sores, canker sores are not contagious and cannot be spread with transfer of saliva, or sharing of foods and beverages.1 But like cold sores, canker sores are painful, and can take up two weeks to heal.

The origin of canker sores is unknown.1 It is assumed that a combination of different factors contributes to outbreaks best diet pills. Some of these factors include trauma to the mouth from dental work or acidic foods, emotional stress, or even toothpastes and mouth rinses containing sodium lauryl sulfate.1 Canker sores are not associated with the herpes virus, and usually heal on their own without treatment.1

Treating Cold Sores or Canker Sores

If you feel like you have a cold sore or canker sore, contact your physician so he or she can recommend proper treatment – do not rely on self-diagnosis or unqualified advice found on the Internet.

If you are diagnosed with a cold sore, ask your physician about Sitavig. He or she can properly instruct you on Sitavig dosing and administration.

1- – What is the difference between a cold sore and a canker sore? Is it true that if you have a canker sore, you have herpes?



Sitavig should not be used in patients with known hypersensitivity to acyclovir, milk protein concentrate, or other components of the product.

Sitavig has not been studied in pregnant women or in immunocompromised patients and no interaction studies have been performed. Sitavig’s safety and efficacy have not been established in pediatric patients.
Sitavig is a Pregnancy Category B product; therefore it should be used during pregnancy only if the potential benefit outweighs the potential risk to the fetus. It is not known if Sitavig is excreted in breast milk; however, systemic absorption is minimal.

In a controlled clinical trial Sitavig’s most common side effects (greater than or equal to 1%) were: headache (3%), dizziness (1%), lethargy (1%), gingival pain (1%), aphthous stomatitis (1%), application site pain (1%), application site irritation (1%), erythema (1%) and rash (1%). In the same trial these side effects ranged from 0%-3% for placebo.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088.

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