Stability of pain-related medications, metabolites, and illicit substances in urine (original) (raw)
Abstract
Background: Effective urine drug testing requires an understanding of the stability of medications, metabolites and other substances excreted in the urine matrix. When the testing results do not fit the clinical picture, physicians frequently request repeat testing of the original specimen in order to corroborate the results. We determined the stability in urine of various medications, metabolites, and illicit substances commonly requested for testing by physicians treating patients with pain and pain-related disorders. Methods: Quantitative analyses of urine specimens were performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Two replicates at a high and low concentration were analyzed at time 0, and after 2, 3 and 6 months following storage at +4°C and −20°C. At each time interval, the percent difference from time 0 for each analyte was calculated and averaged for each storage condition. Results: For the majority of medications, the percent differences were within 20% of the original measurement for all 3 storage conditions. All were within 30% of the original measurement after 2, 3 and 6 months in all storage conditions, except for 7-amino-clonazepam, and carboxy-tetrahydrocannabinol. Conclusions: The findings from the current study confirm that the majority of medications, metabolites, and illicit substances commonly requested for testing by physicians treating patients with pain and pain-related disorders are stable within 20% of the original concentration when stored refrigerated or frozen for up to 6 months. Thus, delayed testing, repeat testing, and add-on testing of urine specimens can yield reliable results for up to 6 months following the urine collection date.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.
References (15)
- Chou R, Fanciullo GJ, Fine PG, et al. Clinical guidelines for the use of chronic opioid therapy in chronic noncancer pain. J Pain 2009;10(2):113-30.
- West R, Pesce A, Mikel C, et al. Observations of medication compliance by measure- ment of urinary drug concentrations in a pain management population. J Opioid Manag 2010;6(4):253-7.
- Gourlay DL, Heit HA, Caplan YH. Urine drug testing in clinical practice: the art and science of patient care. California Academy of Family Physicians. Stamford, CT: PharmaCom Group, Inc.; 2010.
- Christo PJ, Manchikanti L, Ruan X, et al. Urine drug testing in chronic pain. Pain Physician 2011;14(2):123-43.
- Frings CS, Queen CA. Stability of certain drugs of abuse in urine specimens. Clin Chem 1972;18(11):1442.
- Paul BD, McKinley RM, Walsh JKJ, Jamir TS, Past MR. Effect of freezing on the concen- tration of drugs of abuse in urine. J Anal Toxicol 1993;17(6):378-80.
- Dugan S, Bogema S, Schwartz RW, Lappas NT. Stability of drugs of abuse in urine samples stored at -20 degrees C. J Anal Toxicol 1994;18(7):391-6.
- Lin DL, Liu H, Chen CY. Storage temperature effect on the stability of morphine and codeine in urine. J Anal Toxicol 1995;19(5):275-80.
- Chang BL, Huang MK, Tsai YY. Total morphine stability in urine specimens stored under various conditions. J Anal Toxicol 2000;24(6):442-7.
- Clauwaert KM, Van Bocxlaer JF, De Leenheer AP. Stability study of the designer drugs "MDA, MDMA and MDEA" in water, serum, whole blood, and urine under various storage temperatures. Forensic Sci Int 2001;124(1):36-42.
- Zaitsu K, Miki A, Katagi M, Tsuchihashi H. Long-term stability of various drugs and metabolites in urine, and preventive measures against their decomposition with special attention to filtration sterilization. Forensic Sci Int 2008;174(2-3):189-96.
- Parlar A, Ayer A, Uzun N, Aydemir N. Effect of storage on THC-COOH level in urine [abstract]. Ther Drug Monit 2011;33(4):491.
- Wad N. Degradation of clonazepam in serum by light confirmed by means of a high performance liquid chromatographic method. Ther Drug Monit 1986;8(3): 358-60.
- Hart BJ, Wilting J, de Gier JJ. The stability of benzodiazepines in saliva. Methods Find Exp Clin Pharmacol 1988;10(1):21-6.
- El Mahjoub A, Staub C. Stability of benzodiazepines in whole blood samples stored at varying temperatures. J Pharm Biomed Anal 2000;23(6):1057-63.