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Clinician’s Corner: Cold Sores

Cold sores are a quite common complaint year-round, but seems to become more frequent this time of the year.  Cold sores occur in 20% – 40% of the US population.  It is estimated that 67% of the population are affected by the virus. For most healthy people the sore goes away on its own but patients seek treatment because of the pain and unsightly appearance of the lesion.

The virus: Herpes viruses live in the nerve fibers, usually in nerves in the jaw. This leads to the occasional breakout of the virus where the site of infection is usually the border of the lips. Patients with oral herpes infection should be informed that herpes viruses can be transmitted through oral sex to their uninfected partner resulting in genital ulcers. 50% of new cases of genital lesions in the developed world are caused by the virus that causes cold sores.

Over the Counter

Zilactin® (benzyl alcohol 10%) which is OTC contains hydroxypropyl cellulose which is a bioadhesive that sticks to mucus membranes and may be used to protect lesions from irritants for up to six hours.  Do not to peel off the adhesive film.  Also, available at Zilactin-B which contains benzocaine 10% is for use inside the mouth to help numb the lesions.

Abreva® contains docosanol needs to be applied five times daily for a maximum of 10 days.  Complete treatment resulted in decreased duration of the lesion by only 18 hours. For a product that costs around $24 and gives less than one day of relief, this is hardly a bargain!

Mechanism: Abreva keeps the virus from attaching to your own cells. The end result is that the virus can’t enter into the host cells and multiply.

Sunscreens: some patients will experience cold sores when they are exposed to large doses of sunlight.  Sunscreens are of great benefit and should be applied before direct sunlight exposure.

Emollients/Protectants: white petrolatum, zinc oxide, cocoa butter relieve cracking and dryness. They do nothing to speed up healing.  Many OTC products are seen in combination with camphor, thymol and benzocaine. Avoid any products that contain salicylic acid that can further break down the affected skin. Many of these products contain sunscreens as well.

Lysine: dosed as 1000mg one to three times daily may show a decrease of frequency of recurrence and severity of the lesions. Is of minimal value.

What does work: Rx antivirals

Our patients with frequent outbreaks of cold sores should have prescription oral antivirals so they can take at the first sign of tingling.  The oral antivirals are very effective if taken early, as soon as tingling begins. Here are the doses for cold sore prevention.

Drug name Brand Dispense Instructions
Acyclovir 400mg Zovirax® #20 capsules Dose: Take one capsule five times a day
Famciclovir 500mg Famvir® #3 tablets Dose: Take 3 tablets as a single dose
Valacyclovir 1gm Valtrex® #4 tablets Dose: Take 2 tablets twice daily for one day

Your Thompson Pharmacist recommends you talk with your doctor or dentist about having a prescription in your medicine cabinet, so when you get that tingling (probably on a weekend!!) you can begin therapy immediately and stop the virus before it even breaks out!

There are ointments and creams containing antivirals such as Acyclovir 5% (Zovirax), Penciclovir 1% cream (Denavir),  Acyclovir-5%/Hydrocort-1% (Xerese) must be applied five times daily. They are not as effective as the oral antivirals and cost more than $500 a tube.  Your Thompson Pharmacist does not recommend these because they are too expensive and do not work!

Your Thompson pharmacist is the best source for all your prescription and over the counter needs.  We will be happy to work with your doctor or dentist to get the best treatment at the most affordable price. At Thompson Pharmacy, it’s all for YOU!