• Highlights
• Introduction
• Symptoms
• Transmission
• Risk Factors
• Complications
• Diagnosis
• Similar Conditions
• Home Remedies and Prevention
• Treatment for Genital Herpes
• Treatment for Oral Herpes
• Resources
• References

Herpes simplex

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of herpes simplex.

Alternative Names

Genital herpes; Fever blisters; Cold sores

Treatment for Genital Herpes

No drug can cure herpes simplex virus. The infection may recur after treatment has been stopped, and, even during therapy, a patient can still transmit the virus to another person. Drugs can, however, reduce symptoms and improve healing times.

Acyclovir and Related Drugs

Antiviral drugs called nucleosides or nucleotide analogues are the main drugs used to treat genital herpes. They are taken by mouth. (Acyclovir is also available as an ointment, but the oral form is much more effective.) These drugs limit herpes viral replication and its spread to other cells. They are not cures, however.

Three drugs are approved to treat genital herpes:

• Acyclovir (Zovirax or generic)
• Valacyclovir (Valtrex)
• Famiciclovir (Famvir)

These drugs are used either episodically or suppressively:

• Episodic treatment is used when a patient has an outbreak or suspects one is going to occur. Outbreaks are usually preceded by prodrome -- a group of symptoms that include itching, pain, or tingling. If the drug is taken when these symptoms first appear, it can help prevent the outbreak from occurring. If the outbreak has already occurred, the drug can lessen the severity of symptoms and speed healing time. For episodic treatment, acyclovir is taken 5 times a day for 5 days, valacyclovir twice a day for 5 days, or famiciclovir twice a day for 1 day. (In 2006, famiclovir was approved as the first one-day treatment for recurrent genital herpes.)
• Suppressive treatment requires taking pills daily on a long-term basis. (Acyclovir and famiciclovir are taken twice a day, valacyclovir once a day.) Suppressive treatment may help prevent outbreaks from occurring. It is generally recommended for patients who have frequent recurrences (6 or more outbreaks per year).

Acyclovir and valacyclovir are also approved to treat an initial attack of herpes. When a patient has herpes for the first time, the drug is taken several times a day for 10 days

Side Effects. Nausea and headache are the most common side effects, but in general these drugs are safe. Although there is some evidence these drugs may reduce shedding, they probably do not prevent it entirely. The use of condoms during asymptomatic periods is still essential, even when patients are taking these medications.

Risk for Resistant Viruses . As with antibiotics, doctors are concerned about signs of increasing viral resistance to acyclovir and similar drugs, particularly in immunocompromised patients (such as those with AIDS). Some experts believe, however, that the prevalence of drug-resistant viruses will be low for many years. They argue that widespread use of antiviral drugs will prevent many cases of herpes from developing and will slow the spread of the disease. Even patients on long-term suppressive drug therapy show few signs of drug resistance. In addition, research indicates that many people infected with strains that appear to be drug-resistant in laboratory tests still respond to these drugs.

Foscarnet

Foscarnet (Foscavir) is a powerful anti-viral drug known as a pyrophosphate analogue, and is the first choice for treatment for HSV strains that have become resistant to acyclovir and similar drugs. Administered intravenously, the drug can have toxic effects, including impaired kidney function (which is reversible) and seizures. Fever, nausea, and vomiting are common side effects. It can also cause ulcers on genital organs. As with other drugs, it does not cure herpes.

Cidofovir

Cidofovir (Vistide) is active against many viruses and may be useful in some cases of HSV. Intravenous cidofovir, for example, may be a good choice for patients with HIV/AIDS or bone marrow transplant recipients whose condition is resistant to acyclovir and foscarnet. Cidofovir shows promise as a topical treatment of recurrent genital herpes infections, although it can have severe side effects, including kidney damage.

Investigational Drugs for Herpes

Helicase-Primase Inhibitors. A new class of drugs, called helicase-primase inhibitors, suppress an enzyme vital for HSV replication and growth. They have shown early promise in animal studies, but it will be some years before they are tested for safety and effectiveness in people.

Vaccines. Some experts believe that developing an effective HSV vaccine is the only practical way to control the disease and the spread of infection. Furthermore, if such a vaccine becomes available, then universal immunization may be the best approach. Vaccines also hold the potential for eliminating latent, lifelong infections.

In 2002, the National Institute of Allergy and Infectious Diseases (NIAID) launched the Herpevac Trial for Women. The NIAID seeks to enroll 7,500 women between the ages of 18 and 30 who test negative for both HSV-1 and HSV-2 infection. The trial is being conducted at more than 40 sites in the United States and Canada. Participants are randomly assigned to receive either three doses of the experimental herpes vaccine or an investigational hepatitis A vaccine. The women will be observed for 20 months following the initial vaccination to determine if they contract genital herpes (or, for the control group, hepatitis A) during this time. The vaccine used in the trial does not contain live virus and will not itself cause infection.

The premise for the Herpevac trial is based on results from two studies published in the New England Journal of Medicine in 2002. In these studies, a glycoprotein D vaccine was effective in preventing genital herpes in women who were not infected with HSV-1 or HSV-2. For uninfected women, the risk of contracting genital herpes was reduced by nearly 75 percent. The vaccine was not useful, however, for women already infected with HSV-1 and was ineffective in men regardless of HSV status.

• Review Date: 10/1/2006
• Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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