Urine drug testing (UDT) remains an effective tool for assessing misuse among patients prescribed opioids for chronic pain. These findings from a review were published in Current Pain and Headache Reports.
In recent years, clinicians have been blamed ─ even prosecuted at times ─ for the increase of opioid abuse in the United States. To ensure safe and appropriate use of these drugs, the choice to prescribe opioid medications must include weighing the potential risks, such as causing unintentional overdose, interacting with concurrent medications, or providing access to opioids by third parties.
UDT not only allows for the assessment of opioid overuse or concomitant use of illicit drugs but may indicate which opioid is appropriate, document absorption and metabolism, and show which drug-drug interactions may occur. Assessing all these factors among patients prescribed opioids is as important as monitoring glycated hemoglobin among patients with diabetes or measuring peak and trough antibiotic levels among patients with infections.
Before prescribing an opioid drug, clinicians should assess the risk for opioid misuse and adherence with either objective or subjective screening tools. Regardless of risk stratification, they should follow the prescription monitoring program of the state of residence.
Patients should be given access to naloxone and tested by UDT 3 times during the first 15 months of use. After the first 15 months, patients who are determined to be at low risk should be screened with UDT at least every 12 months. Patients at intermediate risk should be monitored every 6 to 12 months.
Patients who are at high risk for misuse or noncompliance are generally not good candidates for opioids. If opioid use cannot be avoided, a low dose (10 mg morphine equivalent dose) is recommended, and these patients should be monitored by UDT every 3 to 6 months.
Although UDT remains the gold standard for assessing drug abuse due to its low cost, ease of administration, and high specificity and sensitivity, the risk for false positives from nonillicit substances remains. Clinicians should be aware that some nasal decongestants may cause a false positive result for amphetamines or the sleep aid sertraline for benzodiazepines, among others.
The expected result of the UDT is positive for prescribed drugs and negative for other illicit or licit drugs. If the patient is negative for the prescribed drug, this may indicate the patient is hoarding, engaging in binge use, or diverting the drug to others. For this situation, definitive testing is recommended because false negatives are rare. Alterations to the prescription may be considered, depending on the cause of a negative result.
UDT results that are positive for illicit substances or nonprescribed opioids should be assessed carefully to confirm accuracy. If use of other nonprescribed drugs is the cause, patients should be counseled on potential effects, including overdose death. Discontinuation of prescriptions may be warranted among patients who are using or abusing other substances.
The review authors concluded that UDT remains a valuable tool for assessing patients prescribed opioids and for guiding informed clinical decisions.
Chakravarthy K, Goel A, Jeha GM, Kaye AD, Christo PJ. Review of the current state of urine drug testing in chronic pain: still effective as a clinical tool and curbing abuse, or an arcane test? Curr Pain Headache Rep. 2021;25(2):12. doi:10.1007/s11916-020-00918-z.