Mebeverine (Duspatal®) is a antispasmotic drug which is indicated for the symptomatic treatment irritable bowel syndrome. The SmPC of mebeverine does not mention that mebeverine can produce false positive reactions in amphetamine or ecstasy urine tests.
In March 2016 the Netherlands Pharmacovigilance Centre Lareb received a report of a false positive ecstasy urine instant drug test associated with the use of mebeverine. An additional laboratory urine test showed a negative result for ecstasy. Mebeverine is metabolized via ester hydrolysis to mebeverine-alcohol and veratric acid. Mebeverine-alcohol forms a number of metabolites including some amphetamine-like compounds. These amphetamine-like compounds are responsible for positive test results of the ecstasy instant drug test.
The Netherlands Pharmacovigilance Centre Lareb recommends that patients and healthcare professionals should be warned for the possibility that mebeverine can cause a positive ecstasy or amphetamine instant drug test. The manufacturer of the ecstasy instant drug test was informed about these findings.
More information on the analysis of the report can be found here.