Objective: To use liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis to quantify kratom alkaloids and metabolites in the urine of healthy dogs following a single oral dose of an encapsulated kratom extract and evaluate the accuracy of an over-the-counter (OTC) human kratom urine test for identifying the presence of kratom alkaloids and metabolites in canine urine.
Methods: Urine samples were collected from 8 healthy female Beagles following a single oral dose of an encapsulated kratom extract (8 mg) every 4 hours for 24 hours. Urine concentrations of kratom alkaloids and metabolites were measured using LC-MS-MS analysis. Urine samples were tested with an OTC human kratom urine test for identification of mitragynine and/or 7-hydroxymitragynine.
Results: In this small cohort of dogs, the OTC human kratom urine test demonstrated 100% sensitivity (6 of 6; 95% CI, 60.97% to 100.00%) and 100% specificity (7 of 7; 95% CI, 64.57% to 100.00%) for identifying kratom alkaloids and/or metabolites. Kratom metabolite 7-hydroxymitragynine had higher urine concentrations compared to the parent alkaloid mitragynine.
Conclusions: Kratom is primarily excreted as metabolites in canine urine following oral administration of a single dose. Although these results are limited by the small sample size and wide CIs, the OTC human kratom urine test reliably detected kratom metabolites in canine urine when compared with LC-MS-MS.
Clinical relevance: The results of this study provide a better understanding of kratom elimination in dogs and support the potential utility of an OTC kratom urine test as a diagnostic tool for suspected kratom exposure; however, larger studies are needed to validate diagnostic performance.
Keywords: LC-MS-MS; canine toxicology; kratom; mitragynine; urine test.