Re: Myocardial Infarction Associated with Adderall XR and Alcohol Use in a Young Man

To the Editor: I appreciated the information in this article,¹ as one who specializes in the diagnosis and treatment of attention deficit/hyperactivity disorder. I am curious whether the drug screen urinalysis performed in this case distinguished between amphetamines and methamphetamine; the article noted the patient's sample was positive for methamphetamine.

One patient of mine experienced legal problems when a routine urinalysis in the workplace resulted in positives for both amphetamine and methamphetamine; she was taking plain dextroamphetamine for her attention deficit disorder. The head of the testing laboratory assured me that their test distinguished between these agents and that a positive methamphetamine result suggested abuse whereas the positive result for amphetamines in her case was expected.

I believe the distinction is important to make in order to identify what may be a major complicating condition in a patient, namely substance abuse involving methamphetamine. In the case cited, substance abuse is evident for alcohol, but not for methamphetamines necessarily (though the Adderall was being misused).

I am unaware whether amphetamines metabolize to methamphetamine in the body, resulting in a “false positive” for methamphetamine solely from the use of amphetamines in an appropriate manner. With some drug monitoring systems making the distinction between the two, it seems unlikely.

I welcome any comments on the above.