Is the Dexcom CGM sensitive or affected by Levothyroxine?

I started using the Dexcom in March 2012. It has been amazingly accurate and I love it. Last week, I began taking Levothyroxine and now my CGM is wildly inaccurate about half the time, especially at night.

Has anyone experienced this problem?

Hi Alex, I've been using a Dexcom since September. I've also been taking Levothyroxine for about 25 years. Most of the time my Dex is spot on with accuracy, give or take the % deviation allowed.

You may want to try different sites. Dexcom only approves of using your abdomen but I've found much better accuracy putting the Dex on my arms and even my legs. My arms are my favorite spot and most comfortable. I actually have to pat on my arms to remember which arm I have it on.

I also find that my Dex is more inaccurate when my bg levels are rollercoastering. The Dex seems to have trouble sometimes when it's going up or down in knowing when to stabilize. The more stable my bg, the more accurate the Dex. Eating lower carb has helped me get flatter lines and it's a good feeling to see those nice flat lines on the Dex.

I am on Synthroid, and have been for many years, pre-diagnosis. I have not noticed an issue regarding the Synthroid and the Dexcom. I do notice at night, especially if leaning on the sensor during sleep, that the results are typically a false low or ??? - especially on the first couple of nights after a new sensor is placed.

I have been on levothyroxine without incidence.

Location of sensor has beed big deal with gut useless and 1ot's of points off.

I use arms.

Regarding these sensors, I see a recent article on new sensor technology that states these sensors of Dexcom/minimed suffer from:

sensor is an invader in body and as such body spends its spare time trying to wall off the sensor and/or occlude it. Folks proposing a one year sensor are using titanium shell as that is compatible with body.

Also, becasue no absolute oxygen sensor in present 7 day sensor, sensor is looking at relative changes in h2o2 hydrogen peroxide from chemical reactions and that is why one needs to keep entering timely calibration entries to keep system on track

2932-glucose_implant_sensor_glysyn.doc (117 KB)

Thanks everyone for the info. I have now started using the sensor in my arms, and as everyone else noted, it seems much more accurate. And the levothyroxine effect has gone away, so perhaps it was just a matter of my body adjusting to it.

I really love my Dexcom CGM. It has helped me more in the two months I've used it than anything else has helped me in twenty years. Knowing where I'm going, either up down or steady, is amazing and makes treatment decisions so much easier. Next year, I turn 65 and then it is no longer covered by insurance. That's going to be interesting.

Thanks again.

good luck with medicare.

you will need script/prescription - note - explanation from your doctor as well as log of finger stcks twice a year documenting dr's recommended usage quantity on his script/note.

otherwise one ends up fighting a crew with extra long hairy arms dragging along the ground. for the strips - use a contractor that already bills medicare.

As Alex notes, cgms concept excellent, helpful and extremely useful.

my only beef is with current sensor technology and its irrascability and short life.