Brief Answer:
This may be due to benadryl

Detailed Answer:
Hello,
Thanks for using healthcaremagic.

I read your query and understand your concerns.

Although false positive amphetamine drug screening is described with many of the agents but antihistamine play a significant role in causing false positive test for amphetamine despite the fact that you never tried this substance.

I like to refer this article at medscape which gives comprehensive picture about this problem. http://www.medscape.com/viewarticle/726897.

It clearly states that " Categories of medications included antihistamines, antidepressants, antibiotics, analgesics, antipsychotics, and nonprescription agents. Reports of false-positive results were found for the following formulary and nonprescription medications brompheniramine, bupropion, chlorpromazine, clomipramine, dextromethorphan, diphenhydramine, doxylamine, ibuprofen, naproxen, promethazine, quetiapine, quinolones (ofloxacin and gatifloxacin), ranitidine, sertraline, thioridazine, trazodone, venlafaxine, verapamil, and a nonprescription nasal inhaler.

False-positive results for amphetamine and methamphetamine were the most commonly reported. "

I like to tell you that Diphenhydramine is nothing else, it is benadryl.

Hope I am able to answer your concerns.
If you have any further query, I would be glad to help you.
If not, you may close the discussion and if possible you may rate the answer for me, so that I get a good feedback.
In future if you wish to contact me directly, you can use the below mentioned link:
http://doctor.healthcaremagic.com/doctors/dr-ashok-kumar/67386
Thanks and regards

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Brief Answer:
It is difficult to convince but........

Detailed Answer:
Hello,
Thanks for reverting back to me.

I understand the current issue as many times physician do not believe their patient and more convinced with test.
But whatever the fact you need to deal with available evidence which is available over the internet.
Alternatively call the pharmacist and ask him to provide details about false positive test for amphetamine with benadryl intake. You can show the same evidence to your physician.

Other than that, collect evidence available at pubmed (medical literature). medscape. US drug pharmacy colleges and many more.

Take all the papers and try to convince him that this is due to benadryl and you are not responsible for positive test.

If despite all this he is not convinced ask him to retest for amphetamine using gas chromatography which is advanced technique of measurement and able to differentiate between true amphetamine and benadryl.

'Hope I have answered your query. If you have any further questions I will be happy to help".
Thanks

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