Friday, November 7, 2008

ADHD Medication Dosage Windows

Blogger's note: I was first introduced to the concept of a "window" in the blog of Dr. Charles Parker. I highly recommend it. A link to his site, CorePsychBlog, can be found here. I would like to borrow his "window" analogy, as I think it is a very relevant description for what is going on here.

We have spent quite a bit of time discussing the different medications for treating ADHD. Recent attention has been given to methylphenidate (Ritalin, Concerta, Daytrana) treatment. While the choice of drug is extremely important for treating ADHD, there is often a less discussed, but equally important, factor for medication treatments: the actual dosages used. Of related interest is the timing effect of ADHD medications. If you are interested in the need for proper timing for ADHD medications, please visit the site here.

In treatment areas such as homeopathic medicine, we see that specific volumes and concentrations of the desired compounds are essential for the effectiveness of the agent used. In these treatments, treatment effectiveness depends on extremely low concentrations of the treatment agent being used.

While there are stark differences between standard ADHD medications and homeopathic remedies, it is important to realize one common overlapping factor the two treatments often share is overdosage is countereffective and often harmful. While this seems inherently obvious, it is important to note that "overdosage" here can refer to even a slight excess of medication, and is not limited just to exceedingly high amounts.

Going one step further, we even see that specific ADHD medications actually have completely different modes of action and completely different effects when taken at different dosage levels. For example, a 15 mg dose of Ritalin may not only be "overkill" for a patient who should be taking the 5 mg dose, but the extra 10 mg may actually offset or even counteract the benefits derived from the first 5 mg. We have seen similar effects in previous posts such as the one on tyrosine and clozapine. With regards to the medication and amino acid combination treatment, we see that tyrosine supplementation boosts the effectiveness of clozapine to a certain point, but beyond this point, excess tyrosine is counterproductive. Essentially, tyrosine supplementation follows an upside down "U" curve (see bullet point #6 in this post).

This same effect can also be seen in medications, especially when minimizing negative side effects is a concern. In other words, the ADHD medication dosage window is often extremely small. Given the fact that multiple other factors including diet, sleep patterns, other medications, co-existing conditions and health of the patient, etc. can all interfere with medication effects, it is no wonder that even at the right prescription doses individuals frequently shift between "on" or "off" days for medication-controlled treatments. In the next post, we will be examining the effects of different doses of the ADHD medication methylphenidate (Concerta).