Expert: Nigel Simmons - 11/1/2009

Question
I take xanax every night and have for years for restless legs syndrome my doctor recently gave me a urine screen and my xanax did not show up in my urine.  I take 1 to 2 mg per night most of the time 1 works I also take cimetidine for GURD I read somewhere that this could cause a false negative for xanax but the doctors who prescribed both these medications will not listen.  Also there was a hole in my urine container and had to be transfered to another cup at the time I paid no attention to all this because I had nothing to hide but now it's throwing up red flags everywhere botched urine test is this my urine but can't get an answer and the doctors will not even talk to me.  They discharged me for this reason and basically accused me of giving or worse yet selling my medication I was devastated and humiliated I meed some answers and quick do I need a lawyer or what?  I am not letting this go and will take it as high as I need to because I know I take my medication every night.  I have never had a problem and have always gone to the same medical center for over 10 years nothing like this has ever happened I just don't know what to do I need advice and help!!

Answer
Sandy

I'm not aware of cimetidine causing a false result for drug screens, but it does increase the blood level, and decrease the metabolism of some benzodiazepines such as Xanax. The reduced metabolism could possibly explain a low level in a urine screen. However, if you have been taking both drugs at consistent doses for some time, and have been similarly screened previously, then I would not expect the test result to be any different.

If the specific test product has changed, then possibly the sensitivity is different and low levels of Xanax may not be detected. You would need to confirm this with the testing organisation and the manufacturers of the test itself.

Normally I would suggest a blood test to immediately back up any unexpected result, but that is possibly too late now. Any test is likely to show that you are currently taking Xanax, but I'm not sure whether there is a way to show you have been taking it for a prolonged period.

The manufacturers of the test should also be able to confirm which drugs are known to cause false results, and it seems this information is not always made available to users.

I hope this helps.