Presented at the 2012 AAPM Annual Meeting « Back

Stability of Commonly Prescribed Opioids and Other Pain Medications in Urine

Elizabeth G. Gonzales, BS, egonzales@becausepainmatters.com¹, Gary Ng, MS², Amadeo J. Pesce, PhD DABCC³, Cameron West, PhD¹, Robert West, MS1, Charles Mikel, PhD¹, Sergey Latyshev, MS¹, Perla Almazan, MT(ASCP)⁴, (1) Millennium Laboratories, San Diego, California, (2) SWAFS, San Diego, California, (3) Millennium Research Institute, San Diego, California, (4) ASCP, San Diego, California

Drug testing for patients on chronic opioid therapy requires an understanding of the stability of the excreted drugs and their metabolites in the urine matrix. Physicians often request repeat testing when results do not fit the clinical picture. The purpose of the study was to determine the stability of commonly prescribed opioids and other pain medications in urine. Urine from 80 de-identified specimens from patients with pain were stored at +4°C and analyzed within one day of receipt at the laboratory and then at 30 days and again at 70 days. Quantitative determination of the pain medications was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) at Millennium Laboratories. Stable medications were considered those that the average percent change was within 20% after 70 days. Norfentanyl, oxazepam, fentanyl, tramadol, meprobamate, temazepam, alpha-hydroxyalprazolam, oxymorphone, hydrocodone, hydromorphone, morphine, oxycodone, and norhydrocodone were stable over the 70-day time frame. The average percent change was greater than 20% for nordiazepam, lorazepam, and noroxycodone. In general, the opioid medications are stable and therefore repeat tests of the same sample within a 70-day time frame should provide consistent results using the same test methodologies. Future studies are required to include additional compounds and the increase the length of time of the study.

Funding: None