Hopefully you've read our previous discussion of pharmacogenomics but in case you haven't (and you should), it is the science of personalized medicine (medications and medication-dosing) based on an individual's genetic code. Well, nothing ever stays simple with genetics and although by now it is pretty clear that aside from considering what is knows as functional variation in genetic code (what everyone was talking about during that whole human genome project thing - changes in human genetic code that directly affect protein function) we also need to consider epigenetics - or that part of the genetic code that we used to think meant nothing (right, that was going to work out) and we now know influences that expression of all those other genes we care about.
Well, it seems that some real advances are being made in the area of heart medication in terms of pharmacogenomics. From aspirin dosing to issues concerning medications that help with clotting after open-heart surgery, the medical field has been working hard on figuring out what drugs and what doses people who vary on specific genes should be prescribed. The article by Baye and Wikle that drew my attention back to this topic brings up an important consideration that I believe will play a significant role in making sure that medications for substance abuse benefit equally from pharmacogenomics - what they call biogeographical ancestry. Biogeographical ancestry is the politically correct way of asking where on earth people are from, and given the relatively (a few hundred years) recent mixing of African descendants with people from Central and South America, Caucasians with Africans, and a whole other slew of mixes, knowing ones geographical ancestry adds a whole lot of knowledge to our genetic equation because the genetic code hasn't had the time to mix together fully and so it still clumps together in ways that make analyzing its variability much easier.
What the heck does this have to do with drug abuse you ask? Well even aside from a strong recent push by NIDA director Dr. Nora Volkow, it is becoming clearer and clearer, at least to me, that medication are going to play a bigger and bigger role in treating addictions. Drugs like Vivitrol, Suboxone, and Zyban are making a real difference in the success rates of those seeking help from addictions and I think that as we get better and better at tailoring the drug selection and doses, those medications, and other that haven't even been discovered yet, will help us get over the initial hump in treatment - the danger zone.
You see, most people who abuse drugs are not what we call addicts. They're using more than they should and likely need a nudge from their doctor or some real reason, like a likely oncoming heart attack, to tame their use or stop altogether. In fact, the vast majority of drug abusers stop on their own. However, there's always that group of people who can't stop on their own and even though right now we only get to treat them once they get in real trouble (cops, hospital, marriage, you name it), as we start incorporating screening for drug abuse into our medical system we will begin finding more of them at an earlier point in their drug troubled life. For them especially, but also for the chronic relapsers, these medication can make a world of difference and give them a chance at a life that may otherwise seem impossible - a life without drug abuse.Our experience with bupropion and quitting smoking proves that knowing a person's genetic variability can really help determine their effective use of medications.
But for all the people these drugs help, there are always horror stories about individuals who've become addicts to the medication or for whom the meds themselves produced such horrible side-effects that staying addicted almost seems better. For them, I believe pharmacogenomics will make all the difference. And once we figure out who will and who won't benefit from which drugs at what doses I think that the medical field in general, and substance abuse medication therapy in particular, will benefit greatly.
Baye, T. M. & Wikle, R. A. (2010) Mapping genes that predict treatment outcome in admixed populations. Pharmacogenomics Journal, 10: 465-477
© 2012 Adi Jaffe, All Rights Reserved
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