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Can Cold Medicine Make You Fail a Drug Test?

Case Study: Cough & Cold Medicine Can Produce a Positive Result

Winter is well and truly here and that can only mean one thing – coughs and colds are upon us.

So far in the year 2022, the Australian Department of Health has reported 38,743 flu illnesses. From mid-April 2022, the weekly number of influenza cases in Australia has exceeded the 5-year average.

As drug and alcohol screening becomes a part of a workplace culture within many industries. For employers, it is essential to communicate with employees and make them understand that there are some popular flu & cold medicines that can be confused for illegal substances in the Australian workplace safety standard.

If there is a drug and alcohol testing program at your workplace, then it is important to understand that many of our everyday cough and cold medicines can produce a positive result on a drug test. For example, over-the-counter cough syrups may contain pholcodine, a drug from the opiate family. Opiates are one of the six drug classes included in workplace testing. Not everyone is aware of this, as we discovered at a workplace testing event recently.

We attended a busy office as part of a scheduled testing program. Of the 10 people selected for testing, one worker returned a positive drug test result – and he was incredulous. He could not possibly be positive he said, he does not do drugs and was not on any medication. How could the result be correct?

Our collector calmly explained the result indicated the presence of opiates in his system. She then asked if he had taken any medicine recently, from the doctor or pharmacy. Then the penny dropped.

Turns out this worker had taken some cough syrup that morning. In fact, because he was feeling miserable, he had taken a big swig. At the time of testing, it hadn’t occurred to him that cough mixture would even show up on the test.

When his initial onsite test went to the laboratory, it was indeed confirmed positive for pholcodine, and this was consistent with the cough syrup he had declared.

Workplaces can help avoid these stressful testing situations and ensure safe work activities by communicating with their staff, particularly at this time of year, about medicines at work. Our recommendation is that such messaging include:

  • An appreciation that medicines, even common household names, can produce a positive drug test result.

  • Guidelines for the safe use of medicines.

  • When and how to declare a medication that you are taking.

  • Your process for managing positive drug test results.

We have fact sheets and toolbox talks that can help you deliver this message to your staff. If you would like to find out more, get in touch with DASA today on 1300 230 231 or via an email to


DASA (Drug and Alcohol Solutions Australia) is proud to be leading the way in workplace drug and alcohol testing services throughout Australia. Whether your need is for workplace drug testing and workplace alcohol testing, advice on drug and alcohol policy or ideas on how to communicate your workplace expectations, policies and procedures to your staff, DASA can help. We have the experience, technical expertise and people to lead you to the right solution.


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