BEIJING, July 30 -- The "unwanted" side-effects of certain medications can provide clues to new uses of those medications which otherwise could go unnoticed, according to a team of German researchers.

    The classic example is the anti-impotence drug Viagra, which started out as a treatment for angina - pain caused by too little blood reaching the heart. One of the "unwanted" side-effects of that drug was spontaneous erections in male patients.

    By adjusting the medication's effects on biological molecules, scientists were able to enhance the anti-impotence components of the drug.
It was one of those serendipitous discoveries. The search for an anti-impotence drug might have gone on for years if this chance side-effect had not been detected.

    But looking for such "unwanted" side-effects is not done often enough, according to researchers at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany.

    They have developed a way of standardizing this rule to predict the common targets of different drugs. They now scrutinize hundreds of pharmaceutical drugs for "unwanted" side-effects which could have desirable new uses.

    Dr Peer Bork, from the EMBL's Structural and Computational Biology Unit, says: "Such a correlation not only reveals the molecular basis of many side-effects, but also bears a powerful therapeutic potential.

    "It hints at new uses of marketed drugs in the treatment of diseases they were not specifically developed for."

    Out of a total of 746 marketed drugs, the researchers have found 261 which look as if they might have similar unsuspected applications.

    Twenty of these drugs have been tested and 13 showed they targeted molecules predicted by the similarity of their side-effects.

    Finding new uses for already marketed drugs is much faster than developing newly discovered medicines, which may take 15 years.

    "With some more tests and refinement our method could in future be applied on a bigger scale," says Dr Bork, whose research appears in the journal Science.

    "New drugs could routinely be checked in the computer for additional hidden targets and potential use in different therapeutic areas. This will save a lot of money and would speed up drug development tremendously."

    (Source: China Daily/Agencies)