Cold Sore Antiviral

Valacyclovir is used for treating cold sores and genital herpes. Valacyclovir starts to work immediately in the body after you take it. It can help shorten the duration of an outbreak and reduce the risk of transmitting the virus to others.

Valacyclovir acts through multiple mechanisms to prevent the replication of herpes DNA, preventing the virus from making copies of itself, which is how the virus causes outbreaks. Valacyclovir is active against HSV-1, HSV-2, VZV (the virus that causes chickenpox and shingles), and to a lesser extent, other herpes viruses, like CMV. When viral DNA is prevented from replicating, the virus cannot multiply and infect uninfected cells. This is how valacyclovir works:

• Stops or shortens outbreaks of genital herpes and oral herpes

• Prevents outbreaks of genital and oral herpes

• Decreases the risk of infecting an uninfected partner

Once in the body, valacyclovir starts to work almost immediately. Since it specifically attacks the DNA replication process, it will only attack herpes viruses that are multiplying. While it starts to work on an active infection very quickly, it will not fight the inactive virus hiding in the nervous system.

Nevertheless, if taken daily and used in combination with safe sex practices, it may reduce the number of outbreaks a person might experience by 54% and reduce the risk of transmitting herpes to a partner by about 50%. Taken at the earliest feeling that an outbreak is on the verge of occurring, valacyclovir may either stop the outbreak or shorten how long it will last. Remember, with valacyclovir treatment for herpes, the earlier you take it after the symptoms appear, the better.

While it goes to work within hours of taking the medication, the symptoms and sores of an outbreak may take days to heal, and the virus can stay active throughout the healing process.

Valacyclovir is an antiviral medication that is used to treat oral herpes and genital herpes, which are caused by herpes simplex viruses 1 and 2 (HSV-1 and HSV-2).

Treatment of initial genital outbreak

To treat an initial episode of genital herpes, the FDA recommends taking valacyclovir 1 gram (1000 mg) twice a day for 10 days starting at the first sign or symptom of lesions, preferably within 48 hours of onset. The CDC recommends this same dose for 7 to 10 days; “treatment may be extended if healing is not complete after 10 days.” For HIV-infected patients, they recommend 1 gram (1000 mg) every 12 hours for 5 to 14 days.

Treatment of recurrent genital herpes, including HIV-infected patients

The FDA recommends using 500 mg of valacyclovir twice daily for 3 days starting at the first sign or symptom of lesions—preferably within 24 hours of onset. The CDC also recommends valacyclovir 500 mg twice daily for 3 days, but adds an alternative regimen of valacyclovir 1 g (1000 mg) one time a day for 5 days. Valacyclovir 1 g taken every 12 hours for 5 to 14 days is recommended by the HIV guidelines.

Treatment with suppressive therapy

People with fewer than 10 outbreaks per year should take valacyclovir 500 mg once daily. Valacyclovir 1,000 mg once daily is recommended for people with 10 or more outbreaks per year.

To prevent transmission to a partner

The infected partner should take valacyclovir 500 mg once a day to decrease the risk of transmission to the uninfected partner. The data are strong but refer to patients with 9 or fewer outbreaks each year.

Common side effects of valacyclovir include headache, nausea, and stomach pain. More serious side effects can occur and are more likely if you have a weakened immune system or are elderly.

For more comprehensive information on side effects that can occur with valacyclovir, see full Important safety information here.

Valacyclovir comes in two doses, 500 mg and 1000 mg tablets. Although there are only two doses, there are several ways to use the medicine for different indications. Remember that these doses may need to be changed for people with specific conditions, such as kidney problems. If you’re prescribed valacyclovir, take it according to your prescriber’s instructions.

For genital herpes:

To Treat Or Abort An Outbreak When There Are Early Symptoms (Prodrome) Some patients use valacyclovir to stop an outbreak. Whether oral or genital, people can take medication when their specific prodrome (pre-outbreak symptoms) tells them an outbreak is on the horizon. The medication often stops an outbreak; when it does not, it can shorten and make an outbreak milder than it might have been otherwise.

To Prevent Outbreaks When There Are No Symptoms But Outbreaks Are More Likely Patients also learn the life circumstances or behaviors that lead to more outbreaks. For some, a lack of sleep, increased alcohol intake, another illness, stress, too much sunlight, irritation, or anything that can affect one’s immunity can spur an outbreak. They know when they are more likely to have an outbreak due to their circumstances. They can avoid their triggers, but they also might want to take medication preventatively, knowing when they are more vulnerable.

To Suppress Outbreaks For An Extended Period You can take valacyclovir to reduce your chance of having an outbreak. The classic example would be during your honeymoon, going on vacation, starting a new job, or when you’re in a new relationship, or at any time you want to keep the chance of having an attack as low as possible.

To Prevent Transmission to An Uninfected Partner One of the most important advances in herpes treatment came with the knowledge that transmission from an infected person to their uninfected partner could be reduced. Valacyclovir not only reduces the number of outbreaks a person experiences, but it reduces asymptomatic viral shedding (or how many copies of the virus your body releases). That results in fewer uninfected partners catching herpes. If a condom is worn and the medication used, the chances are reduced by at least half compared to using a condom alone. Fewer outbreaks and fewer episodes of shedding mean fewer people transmitting the virus.

Acyclovir was the first antiviral drug for the treatment of herpes infections. Acyclovir was initially FDA-approved to treat herpes simplex infections in 1985 as the brand name drug Zovirax® and was found to be very effective for treating herpes infections. The main problem with acyclovir is that only 10%–20% of it is absorbed from the digestive tract. Higher doses aren’t as effectively absorbed as lower doses. This made it very difficult to maintain a high enough level of the drug in the blood to be effective, requiring patients to take up to five doses per day.

Valacyclovir is considered a prodrug of acyclovir, which means that it is converted into acyclovir in the body. Since valacyclovir is absorbed much better than acyclovir (54% for valacyclovir vs. 10%–20% for acyclovir), it can be administered less frequently while providing equal or better results compared to acyclovir. Valacyclovir is administered 1 to 3 times daily, depending on what it’s used for, whereas acyclovir is used 2 to 5 times daily, depending on the indication. Doctors and patients prefer Valacyclovir because it is easier to dose and may be more effective.

For genital herpes:

To Treat Or Abort An Outbreak When There Are Early Symptoms (Prodrome) Some patients use valacyclovir to stop an outbreak. Whether oral or genital, people can take medication when their specific prodrome (pre-outbreak symptoms) tells them an outbreak is on the horizon. The medication often stops an outbreak; when it does not, it can shorten and make an outbreak milder than it might have been otherwise.

To Prevent Outbreaks When There Are No Symptoms But Outbreaks Are More Likely Patients also learn the life circumstances or behaviors that lead to more outbreaks. For some, a lack of sleep, increased alcohol intake, another illness, stress, too much sunlight, irritation, or anything that can affect one’s immunity can spur an outbreak. They know when they are more likely to have an outbreak due to their circumstances. They can avoid their triggers, but they also might want to take medication preventatively, knowing when they are more vulnerable.

To Suppress Outbreaks For An Extended Period You can take valacyclovir to reduce your chance of having an outbreak. The classic example would be during your honeymoon, going on vacation, starting a new job, or when you’re in a new relationship, or at any time you want to keep the chance of having an attack as low as possible.

To Prevent Transmission to An Uninfected Partner One of the most important advances in herpes treatment came with the knowledge that transmission from an infected person to their uninfected partner could be reduced. Valacyclovir not only reduces the number of outbreaks a person experiences, but it reduces asymptomatic viral shedding (or how many copies of the virus your body releases). That results in fewer uninfected partners catching herpes. If a condom is worn and the medication used, the chances are reduced by at least half compared to using a condom alone. Fewer outbreaks and fewer episodes of shedding mean fewer people transmitting the virus.

Acyclovir was the first antiviral drug for the treatment of herpes infections. Acyclovir was initially FDA-approved to treat herpes simplex infections in 1985 as the brand name drug Zovirax® and was found to be very effective for treating herpes infections. The main problem with acyclovir is that only 10%–20% of it is absorbed from the digestive tract. Higher doses aren’t as effectively absorbed as lower doses. This made it very difficult to maintain a high enough level of the drug in the blood to be effective, requiring patients to take up to five doses per day.

Valacyclovir is considered a prodrug of acyclovir, which means that it is converted into acyclovir in the body. Since valacyclovir is absorbed much better than acyclovir (54% for valacyclovir vs. 10%–20% for acyclovir), it can be administered less frequently while providing equal or better results compared to acyclovir. Valacyclovir is administered 1 to 3 times daily, depending on what it’s used for, whereas acyclovir is used 2 to 5 times daily, depending on the indication. Doctors and patients prefer Valacyclovir because it is easier to dose and may be more effective.

Cold sores are caused by a herpes virus that spreads through close contact with the infected area of the skin. Cold sores are small, painful ulcers that you get in or around your mouth or nose. It is not known if valacyclovir tablets can stop the spread of cold sores to others.

Genital herpes is a sexually transmitted viral infection. It causes small, painful blisters on your genital area. You can spread genital herpes to others, even with no symptoms. If you are sexually active, you can still pass herpes to your partner, even if you are taking valacyclovir tablets. Valacyclovir tablets, taken daily as prescribed and used with the following safer sex practices, can lower the chances of passing genital herpes to your partner.

Do not have sexual contact with your partner when you have any symptoms or outbreak of genital herpes. Use a condom made of latex or polyurethane whenever you have sexual contact. Ask your healthcare provider for more information about safer sex practices.

Valacyclovir is available as a pill. The pills can appear blue or white, depending on the manufacturer. What’s important is that the active ingredient is valacyclovir, regardless of the pill's color. The color of the pill will not affect how effective your medication is.

Valacyclovir is not an antibiotic. Valacyclovir is an antiviral drug with activity against herpes simplex viruses 1 and 2 (HSV-1 and HSV-2). Valacyclovir attacks the DNA replication process of the virus, so it only attacks herpes viruses that are attempting to replicate actively. While valacyclovir is an antiviral drug that works on active infections, it will not fight the inactive virus and virus that is hiding in the nervous system.