Personalised drugs

The New York Times has an interesting opinion piece on using genetic tests to determine which psychiatric drugs will be most effective and least problematic.

It is starting to become known that people with certain genes or sets of genes react to drugs differently.

These could be genes related to aspects of brain function, or, just as importantly, liver function, because many psychiatric drugs are broken down by enzymes in the liver.

For example, enzyme CYP2D6 metabolises a whole range of psychiatric drugs including antidepressants and antipsychotics.

Some people have certain versions of the CYP2D6 gene which means they have much less of the enzyme and so break these drugs down at a much slower rate.

This means the same dose of the drug in these people will have a much stronger effect, which can lead to increased side-effects.

There are many more examples of how genes influence the effects of drugs, and doctors would ideally like to be able to test people beforehand to see which drugs might be better.

Like most mass-market industries, the drug industry prefers a ‘one size fits all’ approach, advertising their pill as suitable for anyone with a particular condition.

The idea of genetically testing people for drug suitability is causing them a bit of a headache at the moment, as they’re desperately trying to think of ways to make money out of it.

The New York Times article is quite positive about the effect this will have on the relationship between medicine and industry:

Aside from the potential to transform clinical psychiatric practice, these new developments will surely change the relationship between doctors and the drug industry and between the industry and the public. Direct-to-consumer advertising will become nearly irrelevant because the drugs will no longer be interchangeable, but will be prescribed based on an individual’s biological profile. Likewise, doctors will have little reason to meet with drug company representatives because they won’t be able to give doctors the single most important piece of information: which drug for which patient. For that doctors will need a genetic test, not a salesman.

Of course, it could just lead to people with common genes being prescribed cheap, widely available treatments, while those with rarer genetic profiles having to pay more for expensive, niche medicines.

Almost certainly, it will lead to the drug industry getting into the genetic testing market, probably with equally as many advantages and drawbacks as exist with their current marketing strategies.

Link to NYT on ‘On the Horizon, Personalized Depression Drugs’.