Past Issues

Background: Ketamine use disorder has become a major public-health problem. Urine drug screening for ketamine is essential in prevention programs at both individual and community levels. But no data exist for compounds in urine that may interfere with drug tests and cause false-positive results. We suspect that quetiapine may show cross-reactivity in urine drug screening for ketamine. Methods: We recruited 573 patients and divided them into a quetiapine-treated group (QTG) and a quetiapine-untreated group (QUG). Then, we determined the association between the dosage of quetiapine and that of false-positive results. Results: We collected 51 patients in the QTG, and 522 patients in the QUG. In the QTG, 44.2% of patients showed false positive. In the QUG, the ratio of false-positive results was 0.8%. The dose of quetiapine was found to be signifi cantly associated with false-positive results (p < 0.05, odds ratio = 1.415, 95% confi dence interval = 1.013-1.977). But the factors of patients’ sex, age, body weight, height of did not show any signifi cant difference between two groups. Conclusion: Quetiapine is a widely used second-generation (atypical) antipsychotic drug. To avoid mis-interpretating the data and misleading clinical decisions, physicians should be aware of its potential of cross-reaction of ketamine and quetiapine in urine drug screening tests. Double-check for the ketamine use is required to confi rm the ketamine use in quetiapine-medicated patients with ketamine use disorder.