Urine Drug Testing in Cancer Pain Management

Abstract

Urine drug test (UDT) is an effective tool used in chronic opioid therapy to ensure patient adherence to treatment and detect nonmedical opioid use. The two main types of UDT used in routine clinical practice are the screening tests or immunoassays and the confirmatory tests or laboratory-based specific drug identification tests such as gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, or tandem mass spectrometry. UDT produces objective data on some nonmedical opioid use that may otherwise go undetected, such as the use of undisclosed medications, the nonuse of prescribed medications, and the use of illegal drugs. It allows clinicians to initiate an open and effective conversation about nonmedical opioid use with their patients. However, the test has certain limitations that sometimes compromise its use. Its interpretation can be challenging to clinicians because of the complexity of the opioid metabolic pathways. Clear guidelines or recommendations regarding the use of UDT in cancer pain is limited. As a result, UDT appears to be underused among patients with cancer pain receiving opioid therapy. More studies are needed to help standardize the integration and use of UDT in routine cancer pain management. IMPLICATIONS FOR PRACTICE: Despite its potential benefits, urine drug testing (UDT) appears to be underused among patients with cancer pain receiving opioid therapy. This is partly because its interpretation can be challenging owing to the complexity of the opioid metabolic pathways. Information regarding the use of UDT in opioid therapy among patients with cancer is limited. This review article will improve clinician proficiency in UDT interpretation and assist oncologists in developing appropriate treatment plans during chronic opioid therapy.

Keywords: Cancer pain; Nonmedical opioid use; Opioid crisis; Opioids; Urine drug test.

Figure 1

Possible urine drug test findings based on opioid prescribed.^{a a} Using confirmatory tests such as Gas Chromatography/Mass Spectrometry, Liquid Chromatography/Mass Spectrometry. ^b The pharmaceutical opioid and/or its metabolites. ^c As contained in medications such as Tylenol #3 and Tylenol #4. ^d Rarely, morphine may have codeine impurities and oxycodone may have hydrocodone impurities. Note: the presence of 6‐monoacetylmorphine in addition to morphine metabolites in the urine is indicative of recent heroin ingestion.