Treatment for Genital Herpes

Summarized by Robert W. Griffith, MD
May 27, 2002 (Reviewed: April 19, 2004)

Introduction

Genital herpes is one of the most common sexually transmitted diseases. It's usually caused by the herpes simplex virus, type 2 (HSV-2); however, the HSV-1 virus, which generally causes fever blisters or cold sores, is being found more often to be the cause of genital herpes.

Women are more likely to develop genital herpes than men. Being married, having multiple sex partners, and living in the city, all increase the risk of genital herpes.

Many people with herpes don't have any symptoms, or don't realize their symptoms are, in fact, due to herpes. When active, the virus usually causes visible sores in the genital area. The sores cast off (shed) viruses that can infect another person. Sometimes, however, a person can have an episode and have no visible sores at all. This increases the likelihood of spread of the disease, as they don't see the need for treatment or taking precautions during sex (e.g. condom use) to avoid infecting someone else. It's not possible to cure genital herpes, but treatment can reduce or eliminate the symptoms and signs during the occurrence of episodes; however, treatment doesn't necessarily stop shedding of the virus, so temporary abstinence, or precautions during sex, are still necessary.

Present day treatment

The antiviral drug acyclovir was first described 25 years ago, and it has been used for treating genital herpes for almost 20 years. As it's not very well absorbed when given by mouth, it has to be given 5 times a day in a first attack of HSV infection. Two similar drugs, which are better absorbed, have been introduced -- valaciclovir, which can be given twice a day, and famciclovir, given 3 times daily.

All three of these drugs are used to treat first infections. They don't have to be given quite so often in treating repeat episodes, or in suppression therapy (i.e. to prevent the return of episodes); they can be taken only 2 or 3 times a day.

The duration of treatment is normally 5-10 days for first episodes, and 5 days for recurrences. Obviously, having to take a drug frequently for a long period is probably going to lead to lapses in dosing, which in turn is likely to interfere with the success of treatment. It is possible that reduced dosing may be effective in recurrences. A recent report describes the use of acyclovir, given 3 times a day, for just 2 days in treating recurrences of HSV-2; this course was successful in reducing the duration of the sores and the amount of viral shedding (i.e. the infectiousness).

Both famciclovir and valaciclovir have been tested for effectiveness in suppression of recurrences when given once- or twice-daily; and both were found effective using such dosage schemes. While medication is being taken between episodes, shedding of the virus, and hence infectiousness, is reduced still further.

Acyclovir is available as a cream and an ointment for treating HSV episodes. They must be applied 4 to 6 times a day, for up to 10 days. They are considered to be less effective than the oral form.

People with weakened immune systems (e.g. organ transplant recipients, cancer patients given chemotherapy, AIDS patients) may develop HSV that is resistant to acyclovir. They must then be managed with 'second-line' drugs - drugs that can to attack the virus but carry a greater risk of unpleasant side effects. Fortunately, resistant HSV forms are rare in people with intact immune systems.

Possibilities for the future

We can expect to see the introduction of improved antiviral drugs of the acyclovir type, as well as new dosage forms, all aimed at making treatment of the symptoms easier and more effective.

New antivirals are under investigation that attack the viral reproduction cycle at different points. Resiquimod is one of these; it is in the later stages of clinical development.

The main problem in designing new treatments aimed at preventing repeat episodes, or even producing a 'cure', is the way the virus behaves. During an episode, the virus is at the site of the sores (and being shed with cells from the sores), producing the unpleasant symptoms. Between episodes the virus retreats to nerve tissue -- it spends very little time in the blood stream. (Herpes zoster, the chickenpox virus, behaves in much the same way, so that it can re-emerge, sometimes years later, to produce the distressing condition known as shingles.)

Vaccinations against HSV infection have been developed and tested, but the results to date are disappointing. This is partly because plasma antibodies would be relatively ineffective against the hidden virus. However, we may take heart from the fact that a successful vaccine is available for chickenpox, and this is now being tested to see if it can prevent shingles in the elderly.

Having genital herpes often carries a considerable mental burden, especially for planning to start a new relationship. It's important that health professionals give advice that is tailored to the individual patient, with provision of counseling if necessary.

Reducing spread of the disease

Any form of treatment for genital herpes must include specific actions regarding the steps the patient must take to avoid infecting someone else with the virus. Sometimes this may include the use of what are called 'microbicides' -- different agents that can be applied to the genital areas to prevent 'shedding' of the virus. These may be detergents (e.g. nonoxynol-9), surfactants (e.g. poly[sodium-4-styrene sulfonate]), non-penetrant gels, or pH regulators. Obviously condoms, when used correctly, offer one of the best means of controlling spread of the condition. However, total abstinence if either partner has any symptoms of genital herpes is the safest solution. It's important to remember that acyclovir treatment will not prevent the spread of the virus to others.

It's extremely important to manage genital herpes during pregnancy and delivery. The baby can become infected in the womb, during delivery, or afterwards, so that adequate drug treatment and hygienic measures must be effected at the right time during the pregnancy. Untreated herpes in the newborn can result in death in over half the cases, and others may have severe malformations.

Source

• New treatments for genital herpes. R. Snoeck, E. De Clercq, Curr Opin Infect Dis, 2002, vol. 15, pp. 49--55

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