Fever blisters, commonly known as cold sores, are a frequent viral infection. The Herpes Simplex Virus (HSV) causes cold sores/fever blisters There are two types of HSV: HSV-1 and HSV-2. Both types can cause cold sores. Most people with HSV-1 get it as children, through contact with infected saliva. HSV-1 can also be spread through contact with infected skin, such as through kissing. HSV-2 is usually transmitted through sexual contact. 

In this post, we will discuss about what are antiviral medication for cold sores, their benefits, risks, etc. So, let’s get started without any further ado.

What Are Antiviral Medications?

Antiviral medications are medications that are used to treat infections caused by viruses. They work by preventing the virus from reproducing and spreading throughout your body. Antiviral medications can be used to treat cold sores, as well as other viral infections such as shingles and genital herpes. 

Types of Antiviral Medications

Oral Antivirals

Oral antivirals are medications taken by mouth. They are used to treat the initial outbreak of cold sores and can be taken for up to a week. 

The most common oral antiviral medication for cold sores is acyclovir (Zovirax). Acyclovir is taken in pill form, as a suspension (liquid), or as a cream. It can be taken every four hours, five times a day for seven days. Acyclovir is also available in a generic form. Other oral antiviral medications include famciclovir (Famvir) and valacyclovir (Valtrex). These medications are taken two or three times a day for seven to ten days. 

Topical Antivirals

Topical antiviral medications are applied directly to the skin. They come in the form of creams, ointments, or gels. The most common topical antiviral medication for cold sores is docosanol (Abreva). Docosanol is applied five times a day for four days. It can shorten the healing time and may help reduce the severity of symptoms. 

Another topical antiviral medication for cold sores is penciclovir cream (Denavir). Penciclovir cream is applied every two hours while awake for four days. It can also help shorten the healing time and reduce the severity of symptoms.


Prodrugs are medications that are converted into active compounds in the body. They may be more effective than other types of antiviral medications, as they are better absorbed and remain in the body longer. 

Prodrugs like Famciclovir and Valacyclovir have been shown to be effective in treating cold sores. They are taken in pill form and can be taken every eight hours for four to five days. Valacyclovir is also available in a generic form. 

Targeted Therapy Drugs

Targeted therapy drugs are designed to target specific proteins involved in viral replication. There are currently no targeted therapy drugs approved by the United States Food and Drug Administration (FDA) for the treatment of HSV infections. However, there are several investigational targeted therapy drugs that show promise in the treatment of HSV infections, including pritelivir and tabelecleucel-T. 

Benefits of Antiviral Medication

Reduces Duration and Severity of Outbreaks

Antiviral medications can help to reduce the duration and severity of cold sore outbreaks. They work by preventing the virus from replicating, thus reducing the amount of virus present in the body. 

If you take antiviral medication at the first sign of a cold sore (i.e., when you feel that telltale tingling), you can shorten the duration of your outbreak by a day or two. In addition, taking antiviral medication can also help reduce the severity of symptoms like pain and itching. 

Limits the Spread of Outbreaks

Antiviral medications can also help to limit the spread of outbreaks. This is because they help to reduce the number of active viruses in your body, thus making it less likely that you will spread the virus to someone else. 

It is important to note that antiviral medications do not eliminate the virus from your body. Therefore, it is important to still practice safe sex and other hygiene practices to help prevent the spread of cold sores. 

Minimizes Risk of Complications

Antiviral medications can also help to minimize the risk of complications. For example, taking an antiviral medication shortly after you feel the telltale tingling of a cold sore can help reduce the risk of developing a bacterial infection. In addition, taking an antiviral medication can also help reduce your risk of developing other complications, such as corneal scarring or skin discoloration. 

Side Effects of Antiviral Medication

Common Side Effects

The most common side effects of antiviral medications for cold sores include nausea, headache, and stomach upset. These side effects are usually mild and should go away after a few days. 

Some people may also experience dizziness or drowsiness when taking certain types of oral antiviral medications. If this occurs, you should limit your activities and avoid driving or operating heavy machinery until the side effects have subsided. 

Rare Side Effects

In rare cases, some people may experience more serious side effects when taking antiviral medications for cold sores. These may include allergic reactions, kidney problems, and liver damage. 

If you experience any of these symptoms or any other unusual symptoms while taking antiviral medication for cold sores, contact your doctor immediately. 


Antiviral medications are an effective treatment for cold sores. They can help to reduce the duration and severity of outbreaks, limit their spread, and minimize the risk of complications. You can also check our article on Do You Know About Cold Sores On Tip Of Tongue?

For most patients, the benefits of taking antiviral medications for the treatment of cold sores far outweigh the risks. However, it is important to carefully discuss the potential side effects of these medications with your doctor before starting a course of treatment. 

Finally, taking antiviral medications regularly may help to reduce the frequency and duration of cold sore outbreaks. This, in turn, can help to minimize the risk of developing complications and reduce your risk of spreading the virus to other people.

We hope that this article has helped to provide a better understanding of what are antiviral medications for cold sores, how they work, and their potential side effects. If you have any questions or would like to learn more about cold sores, be sure to speak with your doctor for further guidance.