The active substance inhibits the spread of influenza viruses

A well-known medicine has shown an unknown effect against the flu

Influenza A viruses are responsible for many diseases each year. Again and again, these are real epidemics with many deaths. The influenza vaccine can only conditionally protect against a disease, but it is currently the most effective cure for the virus. Finding an effective treatment for influenza is a difficult task for science because influenza viruses have a high degree of genetic mutability and are constantly creating new subtypes. Now, a research team has discovered a new effect on an already known drug that could reverse the trend.

Researchers at the Paul Ehrlich Institute – Federal Institute of Vaccines and Biomedical Drugs – have tested the reaction of influenza viruses to previously approved drugs that were not specifically designed to fight the flu. They discovered that the drug, dextromethorphan, inhibits the spread of the flu virus. Since the drug is already approved, a new flu medicine could be available in a short time. The results were recently presented in Frontiers in Immunology.

A research team has shown in animal experiments that dextromethorphan, a well-known antitussive, inhibits the proliferation of influenza viruses and relieves the symptoms of the flu. (Image: psdesign1 /

Old active substance with newly discovered effect

A research group of the Federal Institute of Vaccines and Biomedical Medicines has used sophisticated analytical methods from drugs known to filter candidates that act on human cellular proteins. Influenza viruses are known to need such proteins to multiply. This resulted in a group of 15 compounds that were tested in the laboratory and in animals for their effectiveness against influenza viruses. One candidate showed a particularly high potential. The drug dextromethorphan resulted in the mice a significant decrease in the amount of disease in the lungs. It also increased the effectiveness of the antiviral agent oseltamivir. Infected ferrets showed a significant reduction in the severity of influenza after the administration of dextromethorphan.

What is dextromethorphan?

The drug dextromethorphan suppresses cough and is used as antitussive (antitussive). In addition, because of its action on the nervous system since 2013, it has been approved for the treatment of mood disorders that can occur during severe neurological disorders.

A new treatment option for the flu?

"Our data suggest that dextromethorphan may be a treatment option for influenza," says Prof. Dr. Veronika von Messling, head of research, in a press release about the results of the study. The drug must now be tested on the human. But since it is an approved active ingredient, the test phase is likely to shorten considerably. (Vb)