Flu drug link to breathing problems
People with lung problems who are taking the influenza drug Relenza should stop using it if they experience asthma-like symptoms.
The warning comes in the wake of multiple reports of bronchial spasms and respiratory malfunction from users of the drug in Europe.
This is the Australian-developed drug's first winter in Europe, and over 500,000 scripts have been issued. Medical Director of Glaxo Wellcome in Australia, Dr Mike Devoy, said problems reported ranged from breathing difficulties to tightening of the airways and wheezing.
The problem was not revealed in trials of the drug, he said, and there were no reports of problems with usage last year during the Australian winter. However, this could be because 1999 was a very low flu season.
Dr Devoy said the company was still unclear if the drug was actually creating the problem. He said it may be possible that people with lung conditions were just noticing preexisting symptoms more after taking Relenza, because it was a new drug.
The company is discussing what action to take with the Australian Therapeutic Goods Administration. This will include alerting doctors and users that there have been reports of patients with lung diseases having worsening symptoms after taking the drug. The warning would be included in patient and doctor product information. In some instances, it said, using an inhaler before taking Relenza may help avoid breathing problems.
Glaxo Wellcome said Relenza belongs to a new class of compounds called neuraminidase inhibitors. Neuraminidase is an enzyme which breaks the bond holding new virus particles to the infected cell. Once broken, the new viruses are free to infect other cells, spreading the infection. Relenza is thought to work by inhibiting breakage of the bond and preventing release of the new viruses and spread of disease.
About 25-50 million people in the United States catch the flu each year, and it kills up to 40,000 people. The direct and indirect costs of flu-related healthcare are about $12 billion per year.