A simple DNA test can now help pinpoint which drugs are going to work best for you
One day we read an article or watch a documentary about some fantastic new technology that sounds like science fiction, and the next day we can get it down at the local mall. That’s the case right now for the latest thing in drug prescribing: pharmacogenomics.
The word is a combination of “pharmaceutical” and “genomic testing.”
Basically it means that you take a DNA test – you give a sample, and they send it to the lab for analysis. What comes back is a report that tells your doctor and your pharmacist which drugs are going to work best for you, which ones might not work so well, and possibly even which ones are likely to cause you serious side effects.
We’ve long known that every person is different, and that not everyone responds in the same ways to any given medication or treatment. One of the best examples – known long before DNA testing was even heard of – involves the powerful pain killer codeine. It’s an opiate, related to morphine, a narcotic and a powerful pain killer. Many people have been prescribed codeine in Tylenol No. 3 or 282’s for severe pain from things such as back injuries.
Codeine is powerful and effective – for about 19 out of 20 people. For the other one out of 20, or about five percent of the population, it doesn’t work at all. For them, it is completely ineffective. That’s because codeine is a “prodrug,” which means that codeine itself doesn’t relieve pain until it’s broken down into other compounds by your body. It’s those other compounds that provide the pain relief. If you’re one of the people whose body doesn’t metabolize codeine, you get no effect.
It used to be that the only way to tell if codeine was going to work for you was to try it. You’d get the prescription, take it for a couple of days and, if it didn’t help, go back to the doctor to try something else.
With pharmacogenomics, we can cut out the trial and error and, if you’re one of that five percent, go directly to a prescription that’s going to work for you right away.
But codeine is just a very clear-cut example.
Pharmacogenomics is already being used very effectively in the prescribing of a wide range of drugs, from blood thinners to cancer treatments to psychiatric medications. In all those areas, the stakes can be a lot higher, and traditional trial-and-error could be a much longer and riskier process.
Pharmacogenomic analysis basically gives you a much better shot at getting the drug that’s going to work best for you the first time out. It’s a really big deal, and we’re going to be hearing a lot more about it as the science and practice develop over the next few years.
But, like all big advances and any kind of DNA testing, it does raise some issues. There are questions of how much you really want to know about your medical future, and issues of protecting the privacy of such intimate information. But the big thing that people in our line of work are already bumping into is more immediate and practical: what if your pharmacogenomic test shows that you’re not going to do well on any of the products covered by your drug plan, but would do better on something that’s not yet covered?
As of today, there’s no easy answer to that last question. It’s something insurers, employers offering plans, and even public policy makers are going to have to address.
As this all goes forward, we’ll do our best to keep you posted.