methadone shows in urine with trimipramine?

Methadone can be detected in urine drug screening tests even when a patient is concurrently taking trimipramine, a tricyclic antidepressant. However, there is evidence that tricyclic antidepressants, such as trimipramine, can sometimes cause false positive results for methadone in enzyme immunoassay-based urine drug screens. This occurs because these immunoassays may cross-react with the tricyclic compounds, potentially leading to a false positive methadone result.

Because of this, UK guidelines recommend that any questionable enzyme immunoassay screening results, especially when involving tricyclic antidepressants, should be confirmed by an appropriate chromatographic technique, which is more specific and can differentiate methadone from tricyclic antidepressants and their metabolites.

Therefore, while methadone itself would normally be detected in urine tests during treatment and has an estimated detectability window of 3–4 days, the concurrent use of trimipramine may affect initial immunoassay results by causing false positives, but confirmatory testing prevents misinterpretation.