Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cold, Flu, & Cough Health Center

Font Size

Some Flu Viruses Resist Drugs

Japanese Scientists Find Flu Virus That Resists Tamiflu, Relenza
WebMD Health News
Reviewed by Louise Chang, MD

April 3, 2007 -- Some flu viruses appear to resist the antiviral flu drugs Tamiflu and Relenza, report Japanese researchers.

They included Shuji Hatakeyama, MD, PhD, a virus expert at the University of Tokyo.

Hatakeyama and colleagues had previously noted cases of influenza type A that resisted Tamiflu. Now, they note cases of influenza type B that show reduced sensitivity to Tamiflu and Relenza.

Hatakeyama's team studied flu viruses from a Japanese epidemic of influenza type B from 2004 to 2005.

The flu specimens came from patients including 74 children who took Tamiflu for five days, 282 untreated children, and 66 untreated adults.

One of the children who took Tamiflu had influenza type B that resisted Tamiflu and Relenza, according to the researchers' lab tests.

Seven untreated patients had influenza type B that resisted Tamiflu and Relenza, the study shows.

The drug-resistant flu had the same symptoms and duration as normal flu. Drug-resistant flu likely spread through the community or among siblings, note the researchers.

Drug resistance in influenza type B seems to be rarer than drug resistance in influenza type A but requires "continued close monitoring," write Hatakeyama and colleagues.

Experts who wrote a journal editorial agree that drug-resistant flu should be watched closely.

The news about drug-resistant flu "is not good," states the editorial. But "an effective response to this news can help contend with the new challenges of influenza," write the editorialists.

They included Anne Moscona, MD, of the pediatrics, microbiology, and immunology departments at Weill Medical College of New York's Cornell University.

The study and editorial appear in The Journal of the American Medical Association.

Tamiflu is made by Roche Laboratories. Relenza is made by GlaxoSmithKline. Both are WebMD sponsors.

In the journal, the editorialists note financial ties to drug companies including Roche and GlaxoSmithKline. The Japanese researchers report ties to other drug companies, but not Roche or GlaxoSmithKline.

Today on WebMD

hot toddy
15 tips to help you feel better.
man sneezing into elbow
Do echinacea and vitamin C really help a cold?
teen girl coughing
Get a good night’s rest with these remedies.
elder berry
Eat these to fight colds, flu, and more.
Natural Cold Flu Remedies Slideshow
cold weather
Allergy And Sinus Symptom Evaluator
Boy holding ear
woman receiving vaccine shot
woman with fever
Waking up from sleep
woman with sore throat