Okay, so it is now three and a half years later, and I have some anecdotal news for you...
I am undergoing some pretty intense back surg in a week and a half, so my neurosurgeon wanted me to stop all anti-inflammatory meds (I've been taking several Ibuprofens a day for quite some time). His only option really was to give me a scrip for Vicodin, and we all know they contain a good deal of acetaminophen. I told him that was fine: of course, my Dex would be adversely affected, but I could just do without it for the few weeks leading up to my surgery, and whatever time it takes to heal up and stop the Watsons post-operatively.
So, I filled the scrip and decided to take one but leave my sensor on, just to see how much things went haywire when the acetaminophen hit my system. And...
That's right, not a thing. The acetaminophen in the pills did NOTHING to disturb my Dexcom G4 system IN ANY WAY. I was a little stunned that I was seeing that the medication had no effects on my CGM, especially since I inadvertently took a Tylenol once when I had the 7+, and it went crazy within minutes of me taking it! I watched my Dex pretty closely for two days, taking my bgs whenever I looked at the Rx for a number. It was entirely undisturbed bythe Vicodins -- readings were all spot on.
I called Dexcom and spoke to a rep for a few minutes about this. She mentioned that they have been working on making acetaminophen less impactful on their systems, but that they were not ready yet to say that they are no longer affected at all. She was real pleased that I was having such good luck, and I couldn't be happier.
Just wanted to let you all know. You may have to do your own tests to be sure what your situation is, but at the least, know that my Dex is okay with Vicodin now.