||Many over-the-counter and prescription drugs can cause positive results on a drug test. Whether or not any particular painkiller will result in a positive test depends entirely on what the active ingredients in the painkiller are.|
Many prescription pain killers contain opiates. Many opiates are detected in the standard drug tests, so morphine or codeine, for example, would likely result in a positive opiates test. Other opiate pain killers are not detected with the standard opiate tests. Oxycodone, for instance, is detected with a standard opiate drug screen (used as the first pass test on urine), but will not be detected by the confirmation tests done by GC/MS. This is because the GC/MS test for opiates looks for morphine and codeine which many opiates break down into. Oxycodone does not break down into morphine or codeine and so is not detected. Doing a web search on the active ingredients listed on the pain killer packaging should turn up specific info about whether or not it is an opiate.
Other pain killers contain acetaminophen. While acetaminophen is not illegal, nor tested for in drug tests, heavy levels can cause a false positive for cannabis. This is relatively unlikely.
There is more information about such interactions in our Drug Testing Vaults.