The FDA has approved the drug Famvir as the first and only one-day antiviral treatment for recurrent genital herpes and cold sores in people with healthy immune systems.

The drug’s maker, Novartis Pharmaceuticals Corp., announced the FDA approval in a news release dated July 28.

At least 45 million people age 12 and older in the U.S. have had a genital herpes infection — or about one in five in that age range, says the CDC.

Before, genital herpes required five days of Famvir treatment — although at a lower dose. Famvir was not FDA approved for cold sores in people with healthy immune systems (meaning those without aids).

The new approval shortens Famvir treatment to a single day at the start of an outbreak and adds cold sores to the drug’s approved uses.

Famvir Dosage

Patients would take 1,000 milligrams of Famvir twice daily for one day at the first sign of genital herpes symptoms, and 1,500 milligrams of Famvir once for one day at the first sign of cold sore symptoms to shorten outbreaks and reduce symptoms.

The drug, available only by prescription, is taken orally.

It does not cure genital herpes or cold sores. Currently, there is no cure for herpes. Antiviral drugs such as Famvir, Zovirax and Valtrex can only help treat or suppress the infection.

Famvir earned FDA approval in 1994 and is used to treat shingles, as well as the herpes virus which causes both genital herpes and cold sores.

Timing Counts

Single-day Famvir should be started within six hours of the first sign of symptoms, such as tingling, itching, burning, or the appearance of herpes sores, says Novartis.

There is "a narrow window of opportunity for treatment" at the start of an outbreak of herpes or cold sores, says Novartis.

Timing is crucial because the virus copies itself most actively in an outbreak’s first hours. Interrupting that process may shorten the outbreak and reduce its severity.

Herpes Virus

There are two types of the herpes simplex virus: herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2).

Cold sores are typically caused by the former, which can spread by kissing an infected person or sharing eating utensils, towels, or razors.

Genital herpes is a sexually transmitted disease (STD) and is usually caused by HSV-2, although it can result from HSV-1.

Most genital herpes patients have few or no symptoms, the CDC notes.

When symptoms appear, there are usually one or more blisters around the genitals or rectum. The blisters can break, leaving tender sores that may take several weeks to heal.

Clinical Trials

Single-day Famvir was tested in clinical trials for treatment of recurrent genital herpes and cold sores.

The genital herpes trial included 329 patients. At the first sign of a herpes outbreak, they got one of two treatments, without knowing which they received:

• 1,000 milligrams of Famvir twice daily for one day
• A pill containing no medicine (placebo).

The Famvir group had milder symptoms and shorter outbreaks that lasted about four days, instead of six days with the placebo, Novartis reports.

Single-dose Famvir had a similar effect on the length and severity of cold sores in the cold sores trial, which included 481 patients, according to Novartis.

More information at Todo en Medicamentos.

The antiviral drug Famvir may curb the shedding of the herpes simplex virus type 2 (HSV-2) in some — but not all — genital herpes patients, a new study shows.

The study was presented today in San Francisco, at the American Society for Microbiology’s 46th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The researchers included Peter Leone,of the University of North Carolina at Chapel Hill.

Before you explore their study, take a moment to review these basic facts on genital herpes:

• It is spread through sex.
• It is most commonly caused by HSV-2.
• It can also be caused by herpes simplex virus type 1 (HSV-1).

At least 45 million people in the U.S. — one in five adults and adolescents — have carried an HSV virus, but many of them don’t know it, according to the CDC.

Genital herpes sores can release the herpes virus. But the virus can also be shed from skin between outbreaks, says the CDC.

That is, it’s possible to spread the herpes virus even if you don’t have herpes sores.

Herpes Study

Leone and colleagues studied 129 people with evidence of HSV-2 virus infection from blood tests. Some had a history of outbreaks of genital herpes while others didn’t.

The researchers randomly split participants into two groups.

Participants in one group took Famvir for 42 days. Then they took a two-week break. Lastly, they took pills containing no medicine (placebo) for 42 more days.

Participants in the other group took the same pills in reverse order. They took the placebo first for 42 days, followed by a two-week break, and then they took Famvir for 42 days.

Participants didn’t know which pills were Famvir.

Each participant also provided daily swabs from his or her genital area. The researchers analyzed those swabs for HSV-2.

Study’s Results

Participants with a history of genital herpes outbreaks showed reduced HSV-2 shedding while taking Famvir, but not with the placebo.

But HSV-2 shedding wasn’t curbed by Famvir in people who had never had a genital herpes outbreak.

Famvir therapy "suppresses HSV-2 shedding in patients with a clinical history of genital herpes," write Leone and colleagues.

More information at Todo en Medicamentos.