Will Effexor cause a drug screen to show cocaine in the system?

Effexor (venlafaxine) is not known to cause a drug screen to show cocaine. Standard drug tests typically screen for specific substances, and while Effexor can sometimes lead to false positives for other drugs, it does not cross-react with cocaine. If you are undergoing a drug test and are concerned about potential interactions, it's best to inform the testing agency about any medications you are taking.