Less than 5% of people whose opioid therapy is managed in a pain management setting test positive for illicit drugs, a new study found.
An analysis of urine drug tests (UDTs) from 600,000 pain clinic patients also shows that those who test positive for their prescribed opioids are significantly less likely to test positive for fentanyl, cocaine, heroin, or methamphetamines — drugs that are most often implicated in accidental overdose deaths.
The findings suggest that careful monitoring of patients on opioid therapy could significantly lower the risk for drug misuse, the investigators note.
“We suspected that, potentially, patients who were taking their opioids might be less likely to use illicit drugs, but we were still surprised at the magnitude of the findings of how low the entire population had in terms of illicit drug use,” lead author Maria Guevara, PharmD, CPE, director of Clinical Affairs, Education and Training for Millennium Health, San Diego, California, told Medscape Medical News.
“Carefully choosing who you prescribe an opioid to tends to make a difference,” Guevara said.
The findings were published in the Journal of Opioid Management.
Researchers at Millennium Health, one of the largest urine test labs in the United States, and Stony Brook University analyzed 600,000 urine specimens collected between January 2015 and September 2021. The median age of participants was 55 years and nearly 60% were women.
Samples were screened for evidence of five commonly prescribed opioids: fentanyl, hydrocodone, morphine, oxycodone, and tramadol. The investigators also examined levels of four illicit drugs most often involved in accidental overdoses: cocaine, fentanyl, heroin, and methamphetamine.
More than 95% of the overall study group tested negative for all four illicit drugs. In addition, 24% of those who had been prescribed opioids were negative for their prescribed medication.
Patients taking their prescribed opioid were 54% less likely to test positive for cocaine (incidence rate ratio [IRR], 1.54; 95% CI, 1.47-1.59), 47% less likely to test positive for heroin (IRR, 1.47; 95% CI, 1.34-1.57), and 35% less likely to test positive for methamphetamine (IRR, 1.35; 95% CI, 1.24-1.45) than were those who were negative on UDT for their prescribed opioid (all, P < .001).
Differences between groups for fentanyl were not significant.
“When pain management with opioids is done carefully and done in clinics where there’s adequate monitoring and offering of alternative therapies, I’m not surprised to see people do well,” co-investigator Steven Passik, PhD, vice president of Scientific Affairs and head of Clinical Data Programs for Millennium Health, told Medscape Medical News.
Researchers also found no significant difference in positivity rates when comparing UDT results collected before and during the COVID-19 pandemic.
The study was not designed to measure adherence, Passik said, and there are several reasons why a patient’s urine sample may have been negative for their prescribed opioid.
Commenting for Medscape Medical News, Andrew J. Saxon, MD, professor of psychiatry and behavioral sciences, University of Washington School of Medicine, Seattle, noted that although the findings are interesting, several questions remain.
Heroin, cocaine, fentanyl, and methamphetamines all have a relatively short half-life, and it is possible some of the samples that tested positive for prescribed morphine may represent heroin use and not pharmaceutical morphine use, said Saxon, who was not involved in the research.
“The paper is silent about how frequently urine testing was done,” he said. “Infrequent testing is likely to miss episodes of illicit substance use.”
In addition, he noted that urine samples analyzed in the study came from patients at pain management clinics, which limits its generalizability to patients whose opioid therapy is managed elsewhere.
“Many patients with chronic pain managed with opioids are seen in primary care settings, where clinicians are responsible for treating patients with a wide array of medical diagnoses, not just pain, and may not have the expertise in treating pain as would pain specialists,” Saxon said.
Another issue of concern was that about one quarter of urine samples from patients with a prescribed opioid showed no evidence of that drug.
“This finding indicates that many patients are having gaps in their adherence,” Saxon said.
“If taken inconsistently, withdrawal symptoms can occur which may lead to instability” and, as shown in this study, greater likelihood of having used an illicit substance, he added.
Passik agreed. “If you have a patient who’s testing negative for their prescribed medication and they have illicit drugs in their urine, they probably need more help within the substance use disorder spectrum,” he said.
Guevara and Passik are full-time employees of Millennium Health, which funded the study. Saxon reported no relevant financial relationships.
J Opioid Manag. 2022;18:361-375. Abstract
Kelli Whitlock Burton is a reporter for Medscape Medical News covering psychiatry and neurology.
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