Resistance grows to anti-flu drugs

Resistance to anti-flu drugs has risen by 12% worldwide in the last decade, scientists said Thursday in a finding that could pose problems for health officials trying to avert a pandemic.

Researchers at the federal Centers for Disease Control and Prevention in Atlanta found resistance to a class of drugs used to treat influenza for more than 30 years rose from 0.4% in 1994-95 to 12.3% by 2004.

In some countries in Asia, drug resistance exceeded 70%.

“Our report has broad implications for agencies and governments planning to stockpile these drugs for epidemic and pandemic strains of influenza,” said Dr. Rick Bright of the CDC.

The findings, which are reported online by the Lancet medical journal, suggest the drugs amantadine and rimantadine will probably no longer be effective for treatment or as a preventive in a pandemic outbreak of flu.

The drugs, known as adamantane derivatives, inhibit the replication of the influenza A virus. But they do not work against influenza B viruses or the H5N1 strain of bird flu that has killed more than 60 people since late 2003.