Can Valacyclovir (Valtrex) Help Prevent Herpes Transmission?

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Valacyclovir (Valtrex), is an antiviral drug used to treat herpes. It is a prodrug, which means it is activated inside the body. Once activated, it inhibits viral DNA replication by the herpes simplex virus. It has been clinically proven to reduce the number of days and outbreaks of herpes.

However it can only help to prevent transmission if used daily. It is important to note that this drug does not cure herpes. It helps prevent outbreaks (although it does not cure the virus), and it helps to prevent transmission of the virus to others. It is also important to note that as with any medication, side effects have been associated with valtrex.

So can Valtrex protect you or your partner from transmitting genital herpes? As we know, the virus is spread by skin-to-skin contact, and that even if you have no symptoms, you can still spread the disease to your partner if you are infected. Read on to find out more.

What is Valtrex?

Valtrex is a treatment for herpes, a highly contagious infection. Herpes is an infection by the herpes simplex virus, HSV. There are two types of HSV: HSV-1 and HSV-2. Most infections are caused by HSV-2, which most often causes genital herpes. HSV-1 typically causes infections above the waist (e.g. cold sores or fever blisters around the mouth).

Valtrex works by inhibiting the DNA replication of HSV. It also helps reduce the duration and severity of outbreaks. Valtrex can also be used to treat chickenpox.

What's the Likelihood of Spreading Herpes While Taking Valtrex?

It is never a 100% chance that you won't spread the herpes virus to your partner. However, if you take Valtrex every day as prescribed, your outbreaks and symptoms should decrease, and the chances of transmitting the virus will also decrease.

A study published in the Journal of the US National Library of Medicine showed that taking Valtrex daily can greatly reduce transmission of the virus to your partner. Many estimates claim that it reduces the risk to around 50%.

Keep in mind 50% is still not a good probability, and barrier contraceptive methods should also be used with partners who may have a sexually transmittable disease. In each case, taking both Valtrex daily and also using a barrier (such as a condom) is still not a guarantee that the herpes virus will not be transmitted to partners.

It is important to note that clinical studies have been performed specifically with Valtrex, so it is not possible to conclude that the same results will occur with other antiviral drugs.

Other Ways to Prevent Transmission of Herpes

Besides taking Valtrex, there are other ways to help prevent transmission of herpes:

Do not have sex when you have sores. These are the most contagious.

Always use latex condoms. Condoms are the best way to prevent transmission of sexually transmitted diseases.

Wash your hands with soap and water after touching the sores and before touching your eyes or mouth.

Use condoms and barrier methods consistently and correctly during all sexual encounters.


Valtrex is not a cure for herpes. It helps reduce the severity and duration of outbreaks and can help prevent transmission. But it can only help if you take it every day.

Valtrex is used to treat herpes and chickenpox. It comes in pill form and is taken once daily. It is important to start Valtrex as soon as possible to prevent outbreaks. Consult with your doctor before starting Valtrex to make sure it is right for you.

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This blog post is for educational purposes only and does not constitute medical or other professional advice. Your specific circumstances should be discussed with a healthcare provider. All statements of opinion represent the writers' judgement at the time of publication and are subject to change. Phoenix and its affiliates provide no express or implied endorsements of third parties or their advice, opinions, information, products, or services.

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