In the 2008 edition of "Harrison's Principles of Internal Medicine," University of Washington Professor of Virology Dr. Lawrence Corey explains that more than 90 percent of the population eventually acquires the herpes simplex virus that causes fever blisters. While prescription antiviral drugs work well, Corey says that doctors usually reserve them for patients with severe, prolonged or recurrent fever blisters. The Food and Drug Administration also allows just one over-the-counter medication, topical docosanol, to claim effectiveness in reducing the severity and duration of fever blisters.
Indications
According to Corey, the Food and Drug Administration approved docosanol, a 22-carbon fatty alcohol, for use on recurrent episodes of fever blisters. No over-the-counter medication has been approved to treat a first-time outbreak of fever blisters. However, this does not mean that the medication isn't safe during the first outbreak--just that it hasn't been proven effective. Docosanol comes in a standard 10 percent strength white cream that dries with a clear finish. Patients apply docosanol fiver times per day until lesions heal. However, docosanol does not work on fever blisters inside the mouth or nose. Pregnant women and children younger than 12 should not use docosanol, except as recommended by a doctor.
Effectiveness
In the 2008 edition of "Basic and Clinical Pharmacology," University of California San Francisco Professor of Medicine Dr. Sharon Safrin explains that docosanol works by preventing the virus that causes fever blisters from entering skin cells. According to Safrin, clinical studies show that docosanol accelerates healing of recurrent fever blisters by about 18 hours and offers interim relief from pain or itching. Docosanol does not destroy the herpes simplex virus or reduce the likelihood of fever blister recurrence. For maximum effectiveness, patients should start using docosanol when they experience prodromal symptoms of fever blisters such as tingling, itching or burning.
Side Effects and Complications
Docosanol is a common ingredient in cosmetics and personal care products, so it is generally safe and well-tolerated. MayoClinic.com reports that the most common side effect of docosanol is headaches. A smaller number of patients experience acne, burning, dryness, itching, redness, rash, soreness or swelling. Patients who experience severe side effects should discontinue use and contact their doctors for further instructions. Fever and pus or thick, white exudate suggests that the fever blisters has become infected with bacteria. Washing hands before applying docosanol can reduce the risk of this complication. Patients who exhibit signs of infection should contact their doctors without delay.
References
- "Harrison's Principles of Internal Medicine, 17th Edition"; A.S. Fauci et al.; 2008
- "Basic and Clinical Pharmacology, 11th Edition"; B.G. Katzung et al.; 2008
- MayoClinic.com: Topical Docosanol
