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By Miranda Hitti
WebMD Health News
Reviewed By Louise Chang, MD
on Wednesday, August 02, 2006
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.
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.
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.
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.
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.
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.
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.
Novartis is a WebMD sponsor.
SOURCES: News release, Novartis Pharmaceutical Corp. WebMD Medical Reference: "Understanding Cold Sores: The Basics." CDC: "Genital Herpes: CDC Fact Sheet."
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