Can sudafed cause a false positive for amphemines?

Yes, Sudafed (pseudoephedrine) can potentially cause a false positive for amphetamines in drug tests. This is because pseudoephedrine is chemically similar to amphetamines, which can lead to cross-reactivity in certain immunoassay tests. However, confirmatory tests, such as gas chromatography-mass spectrometry (GC-MS), can differentiate between the two substances. If you are concerned about drug testing, it's advisable to inform the testing facility about any medications you are taking.