Why Is My Patient Still in Pain?

As pharmacists and caregivers, we have all experienced situations in which patients and loved ones continue to experience pain after being treated with proven, advanced analgesics. It leads us to question whether the correct dose was administered, whether the appropriate diagnosis was made, and even whether some other physiologic or psychologic condition is involved. We have also questioned why some individuals respond very well to certain analgesics, whereas others have limited or no response to the same medication at the same dose. We are now learning more about the impact of pharmacogenomics on the effectiveness and safety of medications, including analgesic agents used for the treatment of chronic pain.

In the main article of this publication, the author provides an overview of the various genetic factors that may affect the safety and efficacy of commonly used analgesics. The topics discussed include the importance of cytochrome P450 enzymes, uridine diphosphate glucuronosyltransferases, P-glycoprotein–mediated drug transport, opioid receptors, and catechol-O-methyltransferase for the management of chronic pain. This provides important insight into the influence of pharmacogenomics on chronic pain management.

Pharmacogenomics is the study of genetic differences that are responsible for the variability in response to drugs and metabolism among individual patients.¹ The goal of this research is to provide valuable information for personalized medicine—that is, giving a patient the right medicine at the right dose. Although pharmacogenomics should allow pharmaceutical companies to develop safer, more effective drugs,¹ many challenges still remain. These include the lack of rapid, automated genome analysis for all individuals, the need for a greater understanding of the genes involved in disease and drug interactions, and the complexity of the disease.¹ This last point is a very important one and is also the greatest challenge in the field of pharmacogenomics. Even with the identification of various genes, transport mechanisms, and receptors that impact the safety and effectiveness of analgesics used for chronic pain, we still do not fully understand why some patients react differently from others to the same agents delivered at the same doses.

The latest thinking is that both genetic and nongenetic factors influence a patient’s response to specific therapies.² This hypothesis has been published with respect to anti-inflammatory agents² but can probably be extrapolated to analgesics as well. For example, genetic variants among individuals may ultimately determine a patient’s clinical response to a particular treatment.² The broad consensus is that additional research needs to be conducted to answer the question, “Why is my patient still in pain?” In the interim, it is up to us as healthcare professionals to provide the best care possible and to promote additional research so that this perplexing question can finally be answered.

References

1. Gosavi DD, Pawar GJ. Pharmacogenomics: promises and challenges. Int J Res Pharm Biomed Sci. 2011;2:1444-1448.
2. Maranville JC, Di Rienzo A. Combining genetic and nongenetic biomarkers to realize the promise of pharmacogenomics for inflammatory diseases. Pharmacogenomics. 2014;15:1931-1940.