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Acyclovir Helped to Control Chronic Cold Sores

The prescription cream acyclovir can help prevent recurrent cold sores and speed healing if an outbreak begins.

Cold sores are caused by a virus, herpes simplex 1 (HSV1), that nearly everyone is exposed to at some point or another. This virus has variable effects on individuals: some people never get cold sores, while others get them occasionally. Some folks suffer with recurrent cold sores that can have a deleterious effect on quality of life.

Although there is no cure for HSV1, there are medications developed late in the 20th century that can do a very good job at controlling cold sores and reducing the number of outbreaks. The first of these medicines was acyclovir. This reader has found it very helpful:

Q. I’ve been suffering badly from recurring cold sores for years. I’d only get a day or two between outbreaks most of the time.

L-Lysine Was Not Enough:

I found L-lysine helped, but I had to take high dosages to get the benefit. It also caused weird side effects like serious constipation so I didn’t want to take it every day for prevention.

Acyclovir Cream to the Rescue:

My doctor prescribed acyclovir cream. It helps a lot.

I’ve got a routine that has the healing time down to only three days. The second I think I’m getting a cold sore, I put ice on it. I’ve had a pulsing spot become a hardly noticeable scab instead of a gross blister. The acyclovir ointment helps too, along with L-lysine.

Acyclovir Was a Breakthrough:

A. Acyclovir (Zovirax) was the first antiviral drug approved for treating herpes labialis, the medical term for cold sores.

During the drug’s development, in the late 1970s, most doctors were extremely skeptical that it would even be possible to find a compound with antiviral activity. Amantadine had already been introduce to fight influenza virus, but many physicians were only familiar with its use to treat Parkinson’s disease. Its antiviral properties flew under the radar.

As a result, when acyclovir was introduced, it had to overcome this bias. Acyclovir has been available as a topical ointment since 1982. The pills were first sold in 1985. Both formulations are now available generically at a substantial discount from the brand name price the manufacturer charges for Zovirax.


There are other prescription drugs that can be used to treat cold sores. Both valacyclovir (Valtrex) and famciclovir (Famvir) are available in pill form, but they are pricey.

Topical creams available by prescription include penciclovir (Denavir) or a combination of acyclovir and hydrocortisone (Xerese). There is also a topical medicine that can be purchased without a prescription, docosanol (Abreva).

There is further reading about cold sores, especially some of the home remedies people use to speed their disappearance, at this post.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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