- When they are used for treatment of depression and ADD simultaneously: Dexedrine, Adderall and Adderall XR, and Vyvanse
- -by blocking the metabolic pathway of AMP, ‘CYP450 2D6′
- -and have reported on this interaction vigorously for 2 years now [this is a picture of CYP450>>]
- -they cause the AMP to accumulate over time
- -the outcome is irritability, loss of focus, and frequently increased dosage to correct the inattention caused by the toxicity – making the patient doubly toxic, even more inappropriate
Those researchers, Cozza, Armstrong and Oesterheld, who constantly report on drug drug interactions [DDI], have confirmed what I have seen in the office since 1996 – regarding 2D6 interactions and my experience of regularly witnessing reactions to Prozac and Paxil with Adderall in hundreds of cases over many years.
Now we have a new kid on the interaction block: Antihistamines
In comments on another CorePsychBlog post regarding ADD and Vyvanse titration Eddie brought to my attention another drug drug interaction you should know about:
Antihistamines and 2D6 Interact: Antihistamines block 2D6 as well. For complete transparency, you must know that I keep the Cozza, Armstrong and Oesterheld book right by my side all day every working day, but this is still a new one for me. I haven’t been watching for this interaction, but it looks like something we should all keep on our radar. Review this article on Antihistamines and 2D6, relevant for AMP, less so for methylphenidate. This table breaks down different generations of antihistamines – and in the body of the article indicates more about 2D6 interactions than is on this table.
This warning is not dire, – it’s not necessary to exclude the more efficacious AMP from your treatment program, just watch for a possible reaction. Most often these reactions aren’t dangerous, but create treatment adverse consequences that cause the team to stop the better [AMP] intervention.
This report from the article:
“The “classic” or sedating antihistamines, with diphenhydramine (Benadryl® and others) as the prototype, are greatly effective but rife with side effects, most notably sedation. In fact, they are often found in over-the-counter sleeping aids, allergy remedies, and numerous multicompound preparations for “colds and flu.” Finkle et al.3 indicated that 47% of people with allergies take over-the-counter medications that typically contain a first-generation antihistamine.”
This will be interesting to watch, and may be contributory to some of the “unpredictable” reactions with stimulants.
And, by the way, when you read it you will be reading also about the “narrowing of the Therapeutic Window” in their report – for many more articles on ‘The Therapeutic Window with ADD Treatment’ drill down to the bottom of this EzineArticles page.
Thanks Eddie, – thanks Cozza, Armstrong, and Oesterheld