Research is underway to find out which patients with chronic pain can benefit most from the use of opioids to control pain. The word opioid refers to substances that act like morphine in the body. These are natural or manmade and have effects like the opium poppy.
The specific focus of this article is the effectiveness of opioids for chronic noncancer pain (CNCP). Several questions were raised. Is there evidence that opioids can be used with certain subgroups of chronic pain patients? Are the current clinical guidelines in use actually based on evidence available?
The current biopsychosocial theory of pain explains why some people develop chronic pain and others do not. This model suggests there are multiple factors that interact with each other to produce chronic pain. This includes biologic, psychologic, emotional, and social factors.
The studies reviewed showed that there are some risk factors to predict a poor outcome. Such things as a previous history of abuse, younger age, and pain at multiple sites or a lower pain threshold may interact together to move someone from acute to chronic pain.
There's evidence that combining a wide range of treatment approaches may produce the best results. This could include psychologic or behavioral therapy, medications, physical therapy, or surgery. Whether or not opioids should be used right away or reserved for use when nothing else helps remains a hotly debated topic.
That's why more researchers are looking for ways to predict who might benefit from these medications -- not just who is more likely to misuse or abuse these drugs. The goal is to assess each patient and plan treatment that is individually tailored for that person. The final outcomes should be pain control, increased function, and improved quality of life. The idea is to provide these benefits while avoiding addiction or undermanagement of pain.
More information about pain mechanisms may be helpful. Genetic factors, psychologic health, and sensitivity to pain may be interconnected. Mood changes seem to be related to chronic pain more than intensity of pain. The results of several studies show that pain amplification and even catastrophizing pain may have an underlying genetic factor.
Other genetic factors are being considered. For example people metabolize drugs or move the drug through the body differently based on genetic traits. Type of pain receptors in the brain and in the body may be genetically determined. Even the tendency to become dependent or addicted to a drug may have a genetic basis.
In the future, it might be possible to do a simple genetic screening test to predict who might benefit from opioid use. Not only that, but physicians may be able to even predict which class of drugs or specific medication would work best for each patient.
Current clinical guidelines do not appear to be based on scientific evidence. More studies are needed to guide physicians in dispensing opioids for pain relief when and where these drugs can have the most effect.