What are cold sores?

Cold sores are a common viral infection. They are small fluid filled blisters that appear on parts of the face, usually on the lips and around the mouth. Cold sores have several typical stages of progression:

• Stage 1 -you will feel a tingling, itching or burning feeling

• Stage 2 -appearance of small fluid filled painful blister(s)

• Stage 3 -blisters grouped in patches, burst and scab over

• Stage 4 -scabs heal slowly leaving no visible scar from the cold sore

Cold sores, for most people, usually begin to heal within 10 days without treatment. For some people, it may be appropriate to seek treatment if their cold sores are bigger than normal or take longer to heal than expected.

How do you catch cold sores?

Cold sores are caused by a virus called the herpes simplex virus (HSV). This virus is very common as it is caught by coming into contact with other people with an active infection. Around 70% of American adults have oral herpes (cold sores).

For most people, the virus lies dormant in the skin, suppressed by your immune system. Occasionally the virus reactivates causing a cold sore. This is often when your immune system is temporarily weakened, by example through stress or illness.

As cold sores are caused by a viral infection and there is currently no cure, many people will experience repeated cold sores. This is because the virus repeats the cycle of reactivation over and over again.

When are cold sores contagious?

Cold sores are contagious from the time you feel a tingling, itching or burning sensation on your mouth or face to when the blisters burst, scabbed over and are invisible.

Whilst you have cold sores, avoid sharing eating utensils, drinking bottles or other items that regularly come into contact with your mouth and face. Also, avoid touching the cold sore directly and wash your hands regularly to help prevent the virus from passing from one person to another.

Cold sores and genital herpes

There are two types of herpes virus. Cold sores are typically caused by type 1 virus (HSV-1). HSV-1 can cause sores on the genitals and type 2 virus (HSV-2) can cause sores on the mouth. The virus that causes cold sores can be transmitted to the genitals and anus, potentially causing genital herpes. This is not as common but if you are worried, avoid touching your cold sores, wash your hands regularly and consider treating your cold sore with antiviral medication.

While you have a cold sore, avoid oral sex as this can increase the risk of passing the virus to a partner. Also, use a condom during sex to reduce your risk of contracting or passing on HSV infection of the genitals.

When do cold sores need treatment?

Cold sores are very common and most people do not need treatment. However, if your cold sores occur frequently, are large, painful, prolonged or you are at high risk of serious complications, such as from a weakened immune system, a doctor may prescribe you with an antiviral medication such as Valtrex. To prevent the herpes virus from growing and spreading you will need to take the antiviral medication on the day you notice the cold sore forming.

What is Valtrex?

Valtrex (valacyclovir) is an antiviral drug licensed for the treatment of herpes simplex infections of the skin and mucous membranes causing herpes labialis (cold sores). Valtrex is not a cure for herpes simplex and it does not prevent you from spreading the virus to other people. Valtrex slows the growth and spread of the herpes virus to help the body fight the symptoms of the infection.

To benefit most from treatment of the infection, you should take the Valtrex tablet as soon as the first symptoms appear because the virus reproduces very early.

In one 2003 study stated that people who took Valtrex, within two hours of noticing their first cold sore symptoms, had shorter cold sore episodes by one day compared to people who did not take Valtrex at all.

How to take Valtrex?

For the treatment of your cold sores, take the Valtrex tablet with or without water, at the first sign of your cold sore symptoms (such as tingling, burning, blisters). The usual dose is 2000 mg (two 1000 mg tablets or four 500 mg tablets) twice a day. The second dose should be taken 12 hours (no sooner than 6 hours) after the first dose. You should take Valtrex for one day (two doses) only. While taking Valtrex make sure you drink lots of water throughout the day.

Do I need medical advice before taking Valtrex?

For certain people, Valtrex may not be the best choice of antiviral medication. Talk to your doctor and do not take Valtrex if you have:

• Kidney problems (damaged kidneys/reduced kidney function).
• Liver problems
• damaged or weakened immune system (immunocompromised)
• are over 65 years old
• an allergic or other serious reaction to Valtrex or any of the ingredients in them
• pregnant or breastfeeding

What is the difference between Valtrex and Valaciclovir?

Valtrex is made by GlaxoSmithKline and is more expensive than Valaciclovir. Valaciclovir is the active ingredient in Valtrex and is available in a generic, unbranded tablet. Valaciclovir and Valtrex are medically equivalent but Valaciclovir is available at a much lower cost.

Generic medicines are required to meet the same standards of safety, quality and efficacy as the branded medication. Therefore, generic medicines contain the same active ingredient and are equally effective and medically equivalent as the branded products but are available at a lower price. Generic manufacturers have to demonstrate that they are medically identical to the branded product - i.e. they offer the same quality, strength, stability and effectiveness.

As with all medicines, this medicine can cause side effects, although not everybody gets them. Valtrex should only be taken after carefully weighing the potential positives and negatives in conjunction with a qualified healthcare professional. The most common adverse reactions reported by patients treated with Valtrex were headache and nausea.

The following side effects have also been reported:

Common (may affect less than 1 in 10):

• Feeling sick
• Dizziness
• Vomiting
• Diarrhoea
• Skin reaction after exposure to sunlight (photosensitivity)
• Rash