Antiviral Medication for Genital Herpes

What is genital herpes?

Genital herpes is an infection of the genitals (penis in men, vulva and vagina in women) and surrounding area of skin. It is caused by the herpes simplex virus. The buttocks and anus may also be affected.

Genital herpes is usually a sexually transmitted infection. Many people who are infected with this virus never have symptoms, but can still pass on the infection to others. If symptoms occur, they can range from a mild soreness to painful blisters on the genitals (vulva, vagina or penis) and surrounding area.

This leaflet just discusses antiviral medication for genital herpes. (See separate leaflet called 'Genital Herpes' for more general details on genital herpes infection.)

What is antiviral medication?

Antiviral medicines to treat genital herpes include: aciclovir, famciclovir and valaciclovir. They work by stopping the herpes virus from multiplying. They do not clear the virus from the body. If an antiviral medicine is started early in an episode of symptoms, it tends to reduce the severity and duration of symptoms during an episode of genital herpes.

Antiviral medication for a first episode of genital herpes

An antiviral medicine is commonly prescribed for a first episode of genital herpes. (A first episode of genital herpes is also called a 'primary' episode.) A five day course of treatment is usual, but this may be extended by a few days if blisters are still forming. With a first episode of genital herpes, the sores and blisters may last from about 10 days up to 20 days. This is usually much reduced if you start an antiviral medicine within five days of the onset of symptoms. The earlier the medicine is started, the better chance of easing symptoms.

Antiviral medication for recurrent episodes of genital herpes

Further episodes of symptoms (recurrences) tend to be milder and usually last just a few days. You usually have 7-10 days of symptoms rather than 10-20 days that can occur with a first episode. Antiviral medication is often not needed for recurrences. Painkillers, salt baths, and local anaesthetic ointment (such as lidocaine) for a few days may be sufficient to ease symptoms. However, an antiviral medicine may be advised for recurrent episodes of genital herpes in the following situations:

• If you have severe recurrences. If you take a five day course of an antiviral medicine as soon as symptoms start, it may reduce the duration and severity of symptoms. You may be prescribed a supply of medication to have ready at home to start as soon as symptoms begin. This kind of intermittent treatment that is just used 'as needed' tends to be prescribed if you are getting severe attacks of genital herpes fewer than six times a year.
• If you have frequent recurrences. You may be advised to take an antiviral medicine every day. In most people who take medication every day, the recurrences are either stopped completely, or their frequency and severity are greatly reduced. A lower 'maintenance' dose rather than the full treatment dose is usually prescribed. A typical plan is to take a 6-12 month course of treatment. You can then stop the medication to see if recurrences have become less frequent. This type of continuous treatment can be repeated if necessary. This type of daily treatment tends to be prescribed if you have severe attacks of genital herpes more than six times per year.
• For special events. A course of medication may help to prevent a recurrence during special times. This may be an option even if you do not have frequent recurrences, but want to have the least risk of a recurrence. For example, during a holiday or during exams.

Antiviral medication for genital herpes whilst you are pregnant

A specialist will normally advise about what to do if you develop genital herpes whilst you are pregnant, or if you have recurrent genital herpes and become pregnant. This is because there may be a chance of passing on the infection to your baby.

A first episode of genital herpes whilst you are pregnant

If you develop a first episode of genital herpes within the last six weeks of your pregnancy, or around the time of the birth, the risk of passing on the virus to your baby is highest (there is about a 4 in 10 chance). The baby may develop a very serious herpes infection if he or she is born by a vaginal delivery.

Therefore, in this situation your specialist is likely to recommend that you have a Caesarean section delivery. This will greatly reduce the chance that the baby comes into contact with the virus (mainly in the blisters and sores around your genitals). Infection of the baby is then usually (but not always) prevented.

However, if you decide against a Caesarean and decide to opt for a vaginal birth, the specialist is likely to recommend that you have antiviral medication (usually aciclovir). This is given intravenously (into your veins) during your labour and birth. The specialist may also advise that antiviral medication is given to your baby after they are born.

If you develop a first episode of herpes infection during the earlier stages of your pregnancy, the risk of passing on the virus to your baby is much lower. Sores or blisters are likely to clear before childbirth, and a normal vaginal delivery is likely to be safe for the baby. Your doctor may suggest that you are treated with antiviral medication at the time of the infection. This helps the sores to clear quickly. In addition, some doctors advise that you should take antiviral medication in the last four weeks of pregnancy to help prevent a recurrence of herpes at the time of childbirth. However, this is not routine and the advantages and disadvantages of taking antiviral medication in the last four weeks of pregnancy should be discussed with you by your specialist.

If you have recurrent genital herpes and become pregnant

If you have recurring episodes of genital herpes, the risk to your baby is low. Even if you have an episode of blisters or sores during childbirth, the risk of your baby developing a serious herpes infection is low. It is not clear why the risk is low, but it is probably because you pass on some antibodies and immunity to the baby during the pregnancy.

However, there is some debate as to what is best if you do have a recurrent episode of sores or blisters during childbirth. Some doctors may recommend a Caesarean section. However, the Royal College of Obstetricians and Gynaecologists does not routinely recommend a Caesarean section if there are blisters or sores due to a recurrent herpes episode at the time of childbirth. Again, this is because the baby is likely to have some immunity to the virus and the chance of the baby developing a serious herpes infection is low.

If you do have a recurrent episode when you go into labour, you should discuss your options with your specialist and together decide the best way that your baby should be delivered.

Another debatable point is whether antiviral medication should be taken in the last four weeks running up to childbirth. This may help to prevent a recurrence of blisters during childbirth. Again, your specialist will be able to advise on the pros and cons.

In summary

A first episode of herpes around the time of birth can be serious for the baby and a Caesarean section is usually advised. In any other situation - an earlier primary infection or a history of recurrent episodes - the risk to the baby is low and your specialist will advise on possible options.

Are there any side-effects from antiviral medicines?

Most people who take antiviral medication get no side-effects, or only minor ones. Read the leaflet inside the medication packet for a full list of possible side-effects.

Further help and information

Herpes Viruses Association

41 North Road, London N7 9DP
Helpline (local rate) 0845 123 2305
Web: www.herpes.org.uk