SATURDAY, Dec. 14, 2002 (HealthDayNews) -- When influenza strikes, you can expect at least a week of misery, with fever, shaking, chills, body aches and headache.
But two relatively new antiviral medicines, approved by the U.S. Food and Drug Administration (FDA) in the last three years, promise to minimize that.
The two drugs, which require a prescription, aren't for everyone, and they don't work if the flu has progressed too far. They're also expensive and aren't a substitute for getting a flu shot. But in some patients, they're worth a try, doctors agree.
Relenza (zanamivir) arrived first, approved in the summer of 1999. Later that year, the FDA also approved Tamiflu (oseltamivir phosphate). Both are known as neuraminidase inhibitors because they block the activity of the enzyme, neuraminidase. If not barricaded, this enzyme breaks the bonds that hold new flu virus particles to the outside of infected cells, allowing new virus to be set free to infect other cells and spread infection.
Relenza is approved to treat flu once it has occurred, and Tamiflu can be used to treat or prevent flu -- for instance, if one member of the household already has flu and others don't want to catch it.
When used to treat flu, there's a somewhat narrow window of opportunity, a fact many patients don't seem to know. The manufacturers of both treatments say the drugs should be taken with two days of the onset of symptoms.
Patients tend to wait too long to come in and request the drugs, says Dr. Thomas Weida, a family physician in Hershey, Pa., and an associate professor of family medicine at Hershey Medical Center, Penn State College of Medicine.
"They come in usually day 3 or day 4," Weida adds.
Even if taken within the recommended time frame, patients can expect the new drugs to shorten their misery by only a day and a half, says Dr. Michael Herbst, a family practice doctor at the Les Kelley Family Health Center in Santa Monica, Calif., and a staff physician at Santa Monica-UCLA Medical Center. "That's not real impressive to me," he adds.
But he concedes that it may be important to some people to shave off that much sick time, in order to get back to work or family responsibilities. And, of course, the drugs may help some people feel better more quickly than that.
The relief doesn't come cheaply. A course of treatment runs about $50 or more, Herbst says.
And the drugs, like most drugs, aren't meant for everyone.
Roche Laboratories, which makes Tamiflu, warns that the drug's safety and effectiveness haven't been determined in people who have chronic heart or lung disease or kidney failure. Among its reported side effects are nausea, vomiting, diarrhea, stomach pain, dizziness, headache and bronchitis.
And Relenza, according to a warning by its manufacturer, GlaxoSmithKline, has caused wheezing or serious breathing problems in some who have used it. Many of those with these side effects had asthma or lung disease already, but not all. As a result, the drug is not generally recommended for use on those with respiratory problems.
Among the side effects reported with Relenza use are headache, diarrhea, nausea, vomiting, nasal irritation, bronchitis, sinus inflammation, dizziness and ear, nose and throat infections.
The new anti-virals attack both influenza A and B, Weida points out. The older anti-virals, including amantadine (Symmetrel) and rimantadine (Flumadine) only wipe out influenza A.
But Weida says that if he knows influenza A is prevalent, he sometimes prescribes the older anti-virals, which are generally less expensive.
Even with the array of anti-viral choices, Weida encourages patients suffering from the flu to take old-fashioned measures as well, including chicken soup. "For some reason chicken soup helps the immune system," he says. "Theoretically, it helps promote anti-viral activity."
He also suggests drinking lots of fluids, getting lots of rest and washing your hands often to minimize the spread of the flu. And if you've got flu, and you're the family cook, delegate that task to someone else until you're not contagious.
What To Do
The U.S. Food and Drug Administration has detailed information on Tamiflu and Relenza.
