Rational Urine Drug Monitoring in Patients Receiving Opioids for Chronic Pain: Consensus Recommendations.

Objective: To develop consensus recommendations on urine drug monitoring (UDM) in patients with chronic pain who are prescribed opioids. Methods: An interdisciplinary group of clinicians with expertise in pain, substance use disorders, and primary care conducted virtual meetings to review relevant literature and existing guidelines and share their clinical experience in UDM before reaching consensus recommendations. Results: Definitive (e.g., chromatography-based) testing is recommended as most clinically appropriate for UDM because of its accuracy; however, institutional or payer policies may require initial use of presumptive testing (i.e., immunoassay). The rational choice of substances to analyze for UDM involves considerations that are specific to each patient and related to illicit drug availability. Appropriate opioid risk stratification is based on patient history (especially psychiatric conditions or history of opioid or substance use disorder), prescription drug monitoring program data, results from validated risk assessment tools, and previous UDM. Urine drug monitoring is suggested to be performed at baseline for most patients prescribed opioids for chronic pain and at least annually for those at low risk, two or more times per year for those at moderate risk, and three or more times per year for those at high risk. Additional UDM should be performed as needed on the basis of clinical judgment. Conclusions: Although evidence on the efficacy of UDM in preventing opioid use disorder, overdose, and diversion is limited, UDM is recommended by the panel as part of ongoing comprehensive risk monitoring in patients prescribed opioids for chronic pain.

Pharmacogenetic testing of CYP2C9 and VKORC1 alleles for warfarin.

American College of Medical Genetics statements and guidelines are designed primarily as an educational resource for medical geneticists and other health care professionals to help them provide quality medical genetic services. Adherence to these standards and guidelines does not necessarily ensure a successful medical outcome. These statements and guidelines should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the health care professional should apply his or her own professional judgment to the specific clinical circumstances presented by the individual patient or specimen. It may be prudent, however, to document in the patient's record the rationale for any significant deviation from these standards and guidelines. Warfarin (Coumadin) is a potent drug that when used judiciously and monitored closely, leads to substantial reductions in morbidity and mortality from thromboembolic events. However, even with careful monitoring, initiation of warfarin dosing is associated with highly variable responses between individuals and challenges achieving and maintaining levels within the narrow therapeutic range that can lead to adverse drug events. Variants of two genes, CYP2C9 and VKORC1, account for 30-50% of the variability in dosing of warfarin; thus, many believe that testing of these genes will aid in warfarin dosing recommendations. Evidence about this test is evolving rapidly, as is its translation into clinical practice. In an effort to address this situation, a multidisciplinary expert group was organized in November 2006 to evaluate the role of CYP2C9 and VKORC1 testing in altering warfarin-related therapeutic goals and reduction of adverse drug events. A recently completed Rapid-ACCE (Analytical, Clinical Validity, Clinical Utility, and Ethical, Legal, and Social Implications) Review, commissioned to inform this work group, was the foundation for this analysis. From this effort, specific recommendations for the appropriate use of CYP2C9 and VKORC1 testing were developed and are presented here. The group determined that the analytical validity of these tests has been met, and there is strong evidence to support association between these genetic variants and therapeutic dose of warfarin. However, there is insufficient evidence, at this time, to recommend for or against routine CYP2C9 and VKORC1 testing in warfarin-naive patients. Prospective clinical trials are needed that provide direct evidence of the benefits, disadvantages, and costs associated with this testing in the setting of initial warfarin dosing. Although the routine use of warfarin genotyping is not endorsed by this work group at this time, in certain situations, CYP2C9 and VKORC1 testing may be useful, and warranted, in determining the cause of unusual therapeutic responses to warfarin therapy.