STEVE INSKEEP, host:
The Food and Drug Administration is requiring a new warning on the label of a widely used anti-flu drug. The drug is called Tamiflu and the warning will say that anybody taking the drug should be watched closely for abnormal behavior, including suicide attempts. Let's find out what this means from NPR Health and Science correspondent Richard Knox. Richard, good morning.
RICHARD KNOX: Good morning.
INSKEEP: What evidence led the FDA to make that warning?
KNOX: Well, the new evidence comes as mostly circumstantial. It comes from Japan. Since 1999 there have been more than 200 cases of bizarre behavior, really - delirium, suicidal behavior, hallucinations, panic attacks, confusion, convulsions. There have been 15 deaths over that seven-year time. And worrisomely, the pace of reports seem to be picking up. It's about half of the total of those 200 had been reported in the past year.
INSKEEP: If these cases have been occurring since 1999, why make the change now?
KNOX: Well, I think part of it is because the pace does seem to be picking up. And because they've been analyzing it over the past year or so and really can't figure out what's going on. You know, the FDA staffers who wrote a report that's going to be considered by the agency later this week, on Thursday, say that they can't tell whether Tamiflu is causing these behavioral disturbances, but they can't rule it out either.
INSKEEP: You mention this is a widely used anti-flu drug. I would imagine a number of people listening right now are taking this drug. Is that fair to assume?
KNOX: Well, we're not really into the flu season yet. There are some cases in North Carolina but not really anywhere else in this country. And it's important to keep this in perspective. The United States uses far less Tamiflu than Japan. Japan uses most of the Tamiflu in the world actually. There are more than six million prescriptions there, written each year, compared to about two million in the United States, which has twice the population.
And Japanese children under 16 get half of these prescriptions. So, you know, in the United States fewer than one in five Tamiflu prescriptions are for children. So, it's not entirely surprising that if there are going to be any side effects from Tamiflu, and especially in children, that you'd see it in Japan.
INSKEEP: Well, when we do get into flu season, should people be wary of taking this? Should doctors be wary of prescribing it?
KNOX: I think we can, you know, again, keeping this in perspective - we have to keep in mind that, you know, 100 cases in the year, which is what they've seen over the past year or so, is really a very, very small proportion of Japanese who are taking Tamiflu. And we also should keep in mind that Japan has monitored closely for complications of flu and it has before Tamiflu came along. So it's possible that Japan is picking up on a lot of the flu complications that we don't. Because, you know, some of the, you know, flu can cause brain swelling in rare cases and that can produce mental changes, and convulsions, and coma.
But the FDA's test says many of these cases are really peculiar, because suicide attempts and jumping out of windows - which has been known to happen on people on Tamiflu - is not known to be associated with the brain effects of the flu. So I think people need to be - you know, it's only prudent, since we don't know what's going on, to use it only when it's necessary. For instance, somebody's who's at risk for flu complications, and to watch them closely when they're on it.
INSKEEP: And in just a couple of seconds, Richard, how effective is this drug at what it's supposed to do?
KNOX: It can shorten the duration of a bout of flu by a day or two, and it reduces flu severity and complications. I think it's important to remember that the best offense against ordinary seasonal flu is flu vaccine, and we've got more of it this year than ever before.
INSKEEP: Okay. Thanks very much. That's NPR's Richard Knox giving us the latest news on Tamiflu, which will now have an FDA warning.
This is NPR News. Transcript provided by NPR, Copyright NPR.
