Pain can have a significant impact on your quality of life, and even affect everyone around you. It can, on its own, have a debilitating effect on your overall health, on your relationships, your ability to complete every-day tasks and the ability to make it through a work day. Uncontrolled pain touches every aspect of your daily life. Unfortunately, it’s often difficult to treat.
Pain is the most common medical complaint of older Americans. Research shows that, as we age, we are more susceptible to degenerative diseases that cause persistent pain, and we are less able to tolerate pain as we age. Joint pain, post-surgical pain and chronic diseases all tend to increase with age.
The mechanism for perceiving pain involves intricate connections among several different regions of the brain, and uses chemicals called neurotransmitters to transmit pain signals. The fact that pain signals are chemical make it possible for medications to play a part in therapy, but finding the right medications can be difficult, and even dangerous.
Types of pain
Pain can be separated into two general classes – acute and chronic. The two are very different and often require different courses of treatment.
Acute pain is usually associated with sudden onset from events like surgery, a traumatic injury, a new disease or inflammation. It can also be associated with new or worsening anxiety and/emotional distress. While pain is a normal, protective response to tissue damage, it can be limiting and cause other issues. Most often, the cause of acute pain can be identified fairly easily and can be treated. In some cases, though, pain can become chronic.
Chronic pain persists over a long period and can be more difficult to manage, especially when considering some medications used for acute pain are not suitable for long-term use and could even cause further problems on their own. Chronic pain demands attentive treatment, though, as lingering pain can lead to problems with simple daily function, cognition and emotional state.
Pharmacogenomics in Pain Treatment
There are several therapies for managing pain that do not include medications, but effective treatment of severe, acute pain and many types of chronic pain often involves medication therapy. Knowing which medications are going to be most effect for that individual can be extremely valuable in speeding time to effective therapy, avoiding negative side effects and even preventing addiction. Using limited genetic testing for just a few genes that impact drug metabolism (pharmacogenomic testing) can give prescribers significant insight into which medications will be safest and most effective for a particular individual.
Opioids are among the strongest medications available, but can also be the most dangerous if prescribed to the wrong person or at the wrong dose. Opioids depend on a specific gene in our bodies functioning normally, but that isn’t always the case. Small mutations in these genes affect our response to medications, and can dramatically change the effect they have on us. These mutations could mean we get no pain relief from them at all, or they could cause a drug overdose that could be harmful or even fatal.
Codeine is the most commonly used opiate in the world, used to treat mild to moderate pain. It’s even on the World Health Organization’s list of essential medicines, but it shouldn’t be used without prescribing informed by pharmacogenomics.
About 10% of all medications in the world are what’s known as prodrugs – an inactive substance that has to be converted in the body to their useful form. In the case of codeine, it relies on CYP2D6 (one of the cytochrome P450 genes) for conversion to morphine. If an individual’s CYP2D6 gene is functioning normally (a standard metabolizer) a standard dose can be prescribed. But if their gene is not functioning as well as expected, they can expect to receive less pain relief from a standard dose. Worst of all, though, is the consequence of having a hyperactive gene, making them an ultrarapid metabolizer. Codeine has been in use for more than 100 years, but we are just now learning more about how it works in our bodies and how we can use the cutting-edge science of pharmacogenomics to prescribe and use it safely.
For a particular gene, it is possible that we are born with multiple copies of the same gene working in our body. So, when one functioning gene is enough to convert codeine into morphine in our bodies, what happens when we have multiple copies of that gene, all doing the same work? We are an ultrarapid metabolizer and end up with increased amounts of morphine in our systems that could be harmful or even fatal, as a standard dose leads to what is actually an overdose for an ultrarapid metabolizer. Depending on the severity, overdose can cause loss of consciousness, depressed breathing and even death.
While many of the most common medications on the market have been around for decades, or even more than a century, we are constantly learning more about how they work and the side effects they may produce in some individuals. As it turns out, genetic differences from person to person are the primary factor responsible for differing responses to medications, making pharmacogenomic testing an invaluable part of personalized, and more effective, healthcare.
Struggling with pain? See below for some helpful resources.
American Chronic Pain Association
theacpa.org
Phone: 916-632-0922 or 800-533-3231
American Headache Society
americanheadachesociety.org
Phone: 856-423-0043
Arthritis Foundation
Arthritis.org
Phone: 844-571-4357
National Headache Foundation
Headaches.org
Phone: 312-274-2650 or 888-643-5552
