A few weeks ago, the mother of a patient in my pediatric practice called me and said that her son had abruptly become much more difficult. The boy, who is wonderfully bright and creative but hard to handle, had been seeing an excellent child psychiatrist and was doing well when suddenly things sort of deteriorated. His mother knew what the problem was and told me: Health Canada (the Canadian equivalent of the FDA) had just banned Adderall XR, the medication he was taking, and—though the drug was still available in the United States—she had asked his psychiatrist to discontinue the treatment.
Adderall XR is used to treat Attention Deficit Hyperactivity Disorder, which lumps together all patients with attention problems—those with hyperactivity and those without it, as in the frenetic child and the space cadet. ADHD can be treated without drugs in a couple of ways. Often, though, (perhaps too often) doctors treat this condition with stimulants—drugs that also suppress appetite and interfere with sleep. At the moment, there are two ADHD drugs in the stimulant class: methylphenidate (Ritalin and Concerta) and amphetamine (Adderall). As far as I've been able to tell, the two kinds of stimulants work just about identically and are equally effective. They also have identical drawbacks: In addition to suppressing appetite and interfering with sleep, they can be abused and they're active for a very short period—a morning dose will usually be ineffective by afternoon. To lengthen the short duration, Adderall combines four different amphetamine compounds, each of which dissolves at a different rate. Adderall XR adds a second delayed-release mechanism to alter the time course slightly and, I suspect, to extend the period of patent protection to wall out the competition (the original Adderall is already available generically).
Why, then, did Health Canada ban Adderall XR while the FDA explicitly did not ban it? Between 1999 and 2003, about a million children, most of them in the United States, took Adderall or Adderall XR. In those four years, 12 boys being treated died suddenly and unexpectedly. At autopsy, five of the children were found to have structural heart problems, some surely present since birth. Of the rest, one was dehydrated after severe exercise in 110-degree weather, two might have been overdosed, and one came from a family with a history of abnormal heart rhythms. The rate of sudden unexplained death in children taking Adderall or Adderall XR averaged 4 per 1 million users per year (and none of the deaths occurred in Canada). For approximately the same age range, the annual cardiac death rate was about 6.3 per 1 million children. Given how similar these two rates are, it seems to me that it would be hard to make the case that Adderall adds significantly to the general risk of heart failure for the young people taking it. Unfortunately, however, there is no way to get at the most important datum: the annual rate of sudden, unexplained death in children with ADHD who were not treated with Adderall or Adderall XR. That means we can't compare the death rate between treated and untreated, but otherwise similar, children.
So, again, why did Canada ban Adderall XR? Frankly, it beats me. Probably the decision reflects simple economics: Because it's under patent, Adderall XR is a lot more expensive than generic versions of Adderall. But if Canada just didn't want to pay the extra cost, I wish the health authorities had owned up to that. When public health policy is submerged in other agendas, we can no longer safely turn to oversight agencies for reliable, trustworthy, and nonpartisan advice.