5 Things You Need to Know About Acyclovir

1. A Really Unfriendly Family

The herpes family of viruses are nastier than Ma Barker and her sons. They are responsible for chicken pox, cold sores, shingles, encephalitis, and genital herpes simplex. In addition, once a person has contracted a herpes infection, he or she has it for life. After the primary infection, the virus goes into a dormant stage and can reactivate at any time.

2. First to Help

Until the development of acyclovir (Trade name, Zovirax), treatments for herpetic infections consisted of amino-acids, herbs and drying agents. While there were many claims that these treatments were effective and "natural," there were no studies that demonstrated their effectiveness. Acyclovir was one of the first anti-viral agents. It is what is called a "nucleoside analogue." These drugs compete with normal DNA building blocks, significantly slowing viruses' ability to reproduce.

3. Two Kinds of Treatment

There are two ways to use Acyclovir. In high doses: 800 mg 3 times per day as treatment for an acute outbreak (so called "episodic use"), or in lower doses, 200 or 400 mg daily as suppressive treatment. Suppressive treatment is primarily for patients with recurrent herpessimples type 1 (cold sores) or 2 (genital herpes). Neither treatment is a cure. Episodic treatment shortens the length and severity of an acute attack, and suppressive treatment reduces the frequency of attacks. But even with early use of acyclovir, there are some residual viruses that retreat into a dormant phase.

4. However ...

Acyclovir is a very safe medication. The most common side effects noted in all its different modes of use are gastrointestinal including nausea, vomiting and diarrhea. However, the incidence of these side effects is less than 3%. As with any medication, there is an extensive list of reactions that have occurred in less than 1% of the drug's administration. These include headache, aggressive behavior, memory loss and rashes.

5. Questionable Uses

In some settings, the use of acyclovir is controversial. These include use during shingles in an attempt to reduce the incidence of a post infection neuralgia (inflamed nerve causing pain), use in healthy children during a chicken pox outbreak, and routine use to prevent genital herpes simplex II recurrences (use in populations that do not have at least 6 outbreaks per year). To date, there have not been large enough studies to determine the effectiveness of these treatments.