During this time of year, questions surrounding common cold medicines and their impact on drug testing results commonly arise. Some common prescription and over-the-counter (OTC) medications may contain drugs such as codeine, hydrocodone, and sympathomimetics, which have been reported to affect workplace drug tests.Codeine. Codeine is used in some medications as a cough suppressant.When codeine enters the body and is metabolized, it changes to morphine. Both codeine and morphine are used to relieve pain. The use of codeine-containing products may result in a positive drug screen for codeine and/or morphine.Hydrocodone. This narcotic is widely used to treat pain and is also FDA-approved for use in a handful of prescription medications as a cough suppressant.t is important that the donor keep a record of any such medications that may affect a drug screen. It is suggested that the donor write a list of these medications on his/her copy of the custody and control form after providing a specimen for a drug screen.