Pharmacogenomics and prescription opioid use

A pharmacogenetic precision medicine approach to analgesia and sedation optimization in critically ill adults

Precision medicine is a growing field in critical care. Research increasingly demonstrated pharmacogenomic variability to be an important determinant of analgesic and sedative drug response in the intensive care unit (ICU). Genome-wide association and candidate gene finding studies suggest analgesic and sedatives tailored to an individual's genetic makeup, environmental adaptations, in addition to several other patient- and drug-related factors, will maximize effectiveness and help mitigate harm. However, the number of pharmacogenetic studies in ICU patients remains small and no prospective studies have been published using pharmacogenomic data to optimize analgesic or sedative therapy in critically ill patients. Current recommendations for treating ICU pain and agitation are based on controlled studies having low external validity, including the failure to consider pharmacogenomic factors affecting response. Use of a precision medicine approach to individualize pharmacotherapy focused on optimizing ICU patient comfort and safety may improve the outcomes of critically ill adults. Additionally, benefits and risks of analgesic and/or sedative therapy in an individual may be informed with large, standardized datasets. The purpose of this review was to describe a precision medicine approach focused on optimizing analgesic and sedative therapy in individual ICU patients to optimize clinical outcomes and reduce safety concerns.

Pharmacogenetic Analysis Enables Optimization of Pain Therapy: A Case Report of Ineffective Oxycodone Therapy

Patients suffering from chronic pain may respond differently to analgesic medications. For some, pain relief is insufficient, while others experience side effects. Although pharmacogenetic testing is rarely performed in the context of analgesics, response to opiates, non-opioid analgesics, and antidepressants for the treatment of neuropathic pain can be affected by genetic variants. We describe a female patient who suffered from a complex chronic pain syndrome due to a disc hernia. Due to insufficient response to oxycodone, fentanyl, and morphine in addition to non-steroidal anti-inflammatory drug (NSAID)-induced side effects reported in the past, we performed panel-based pharmacogenotyping and compiled a medication recommendation. The ineffectiveness of opiates could be explained by a combined effect of the decreased activity in cytochrome P450 2D6 (CYP2D6), an increased activity in CYP3A, and an impaired drug response at the µ-opioid receptor. Decreased activity for CYP2C9 led to a slowed metabolism of ibuprofen and thus increased the risk for gastrointestinal side effects. Based on these findings we recommended hydromorphone and paracetamol, of which the metabolism was not affected by genetic variants. Our case report illustrates that an in-depth medication review including pharmacogenetic analysis can be helpful for patients with complex pain syndrome. Our approach highlights how genetic information could be applied to analyze a patient's history of medication ineffectiveness or poor tolerability and help to find better treatment options.

Drug Design: Where We Are and Future Prospects

Medicinal chemistry is facing new challenges in approaching precision medicine. Several powerful new tools or improvements of already used tools are now available to medicinal chemists to help in the process of drug discovery, from a hit molecule to a clinically used drug. Among the new tools, the possibility of considering folding intermediates or the catalytic process of a protein as a target for discovering new hits has emerged. In addition, machine learning is a new valuable approach helping medicinal chemists to discover new hits. Other abilities, ranging from the better understanding of the time evolution of biochemical processes to the comprehension of the biological meaning of the data originated from genetic analyses, are on their way to progress further in the drug discovery field toward improved patient care. In this sense, the new approaches to the delivery of drugs targeted to the central nervous system, together with the advancements in understanding the metabolic pathways for a growing number of drugs and relating them to the genetic characteristics of patients, constitute important progress in the field.

Feasibility and Acceptability of a Pharmacogenomic Decision Support System in Palliative Care

Context: Pharmacogenomic analysis may improve the efficacy or safety of the drugs used in palliative care. Decision support systems may promote clinical integration of this information. Objectives: To determine the feasibility and acceptability of a pharmacist-directed pharmacogenomic decision support system in the care of patients with advanced illness and explore the drug-gene and drug-drug interactions that occur in this population. Methods: Physicians or nurse practitioners from two U.S. hospice agencies identified opioid-treated patients receiving multiple other drugs. Buccal samples and clinical data were obtained from consenting patients. A pharmacist used the proprietary MedWise™ platform to evaluate the current medications in terms of genotype and phenotype, created a standardized report describing potential interactions and recommended actions that may reduce the associated risk. Clinicians could access the report online and completed Likert-type scales to assess use and satisfaction with the system. Results: Twenty clinicians and 100 patients participated. The reports revealed that 74 drugs were subject to 462 drug-gene interactions and 77 were involved in 691 drug-drug interactions; only 4 and 16 patients, respectively, had no drug-gene or drug-drug interactions. Clinicians routinely checked the reports and used the information to change ≥1 treatments in 55 (55%) patients. Almost all clinicians rated the system likely to improve the quality of care and all "agreed" or "strongly agreed" to recommend the system to colleagues. Conclusion: This pharmacist-directed pharmacogenomic decision support system was perceived positively and was integrated into practice. Further studies are warranted to its clinical integration and its outcomes.