What Causes False Negative Result Of Clonazepam In Urine Test?

Posted on Tue, 15 Jul 2014

Question: I did a recent urine test. My Dr. called to inform me that that my clonazepam did not show up in my urine test. I also have been taking new supplements, they are turmeric supreme 406mg. x2 every morning, Raspberry Ketone 800mg. x2 every morning, generic stool softener 100mg. x4 every morning, Niacin slow release 500mg. x1 every morning, and Percocet 5/325 x2 every day. I take all of my medication. Why is it that my clonazepam is not showing in my urine test. That is the one major medication that I take for my anxiety attacks. The drug does work well. I have been on it for over at least 15 years. Please help!!!

Answered by Dr. Sunil Gupta (20 minutes later)

Brief Answer:
Please see details below.

Detailed Answer:
Hi,

I went through your query in detail and can understand your concern regarding clonazepam not showing up in urine.

Let me clear up something. As long as you know you are taking clonazepam and it is working in controlling your anxiety, you have nothing to worry about.

False-negative tests are quite common for benzodiazepines and is reportedly more common in case of clonazepam. It is reported to be as high as 25-30%. Clonazepam gets metabolized to 7-aminoclonazepam which appears in urine. Most commercially available urine test kits don't test for 7-aminoclonazepam which leads to a false negative urine test.

So, I feel you have nothing to worry. The only thing that is important is that you are taking clonazepam as recommended and it is able to help control your symptoms.

I hope that I was able to answer your query. Please feel free to ask any further query that you might have.

Best wishes,

Dr. Sunil Gupta

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Sunil Gupta (21 minutes later)

My Dr. wants to wean me off because of this. What do I do? She told me to find another dr. ??? And that made no sense to me...Do you think any of the supplement's I am taking would effect the dr.'s urine test?

Answered by Dr. Sunil Gupta (15 minutes later)

Brief Answer:
No, the supplements don't affect the test.

Detailed Answer:
Hi,
Thanks for following up.

I am not too sure why your doctor wants to wean you off this. It might be because she thinks you might be diverting it.

In any case, taperig and weaning off clonazepam would not be a bad idea. Clonazepam has a high propensity to cause dependence. So, using a medicine from the group of selective serotonin reuptake inhibitors (SSRIs) like paroxetine or fluoxetine would be good idea which can take care of your anxiety.

However, you can discuss with your doctor regarding the possibility of a false negative test. I am sure, if you talk to her, she would understand and offer you another test.

And no, none of the supplements that you are taking would affect the urine test result. It may happen if you have drunk lots of water before the test as that will dilute the concentration. But the most feasible cause is the one I gave in the last response.

I hope that answers you query. Please don't hesitate in asking any more query that you might have.

Best wishes,

Dr. Sunil Gupta

Note: For further guidance on mental health, Click here.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar