This post is not interesting to specialists, but
may be of some use to
others. I'm writing it mostly because the matter has been
href="http://www.washingtonpost.com/wp-dyn/content/article/2006/06/12/AR2006061200722.html">reported
in the mainstream press, and I think some clarification is in order.
Wellbutrin XL has been approved by the US FDA, "for the
prevention of major depressive episodes in patients with a history of
seasonal affective disorder."
In this post, I go over some of the history of the product, and try to
explain why the new indication is important, or not. Continue
below the fold...
href="http://us.gsk.com/products/assets/us_wellbutrinXL.pdf">Wellbutrin
XL (package insert PDF) is a brand name for
title="Wikipedia link"
href="http://en.wikipedia.org/wiki/Bupropion" rel="tag">bupropion.
It is the same molecule as
href="http://us.gsk.com/products/assets/us_zyban.pdf" rel="tag">Zyban
(package insert PDF), the smoking cessation
product. It has been used for treatment of major depression
since 1985.
The manufacturer, GlaxoSmithKline, originally marketed an
immediate-release form of Wellbutrin. Several years later,
they came out with Wellbutrin SR. This was done primarily to
enable people to take it only twice per day. With the
original formulation, some people had to take it three times a day.
However, the marketing of a second formulation gave them an
additional period of time under patent protection. 
Shortly before that patent ran out, they came
out with Wellbutrin XL.
The XL formulation can be taken once per day; this is a
reasonable improvement, because it does increase the percentage of
people who will actually take all of their doses. Currently,
Wellbutrin XL is under patent, so there are no generics.
So now, Wellbutrin XL has another "indication." This means
that the FDA will allow them to advertise it specifically for use in
title="Medline Plus link" rel="tag"
href="http://www.nlm.nih.gov/medlineplus/seasonalaffectivedisorder.html">seasonal
affective disorder. It also gives them a little
more time on their patent.
Notice that, so far, I've only mentioned patents and advertising.
That is because the main effects of FDA indications are on
patents and marketing.
When a drug is marketed in the USA, it has to be approved by the FDA.
In order to be approved, it has to be shown to be "safe" and
"effective." Those terms have special meanings in FDA-land.
In order to demonstrate that a drug works, it is necessary to
declare what it is that it is supposed to treat. So the
company that wants to sell the drug declares that it is to be used to
treat condition X. Then then conduct studies to show that the
drug is better than placebo, and that taking the drug is not as
dangerous as having an untreated case of condition X. If they
are successful, the drug is granted an indication for the treatment of
condition X.
Notice that an FDA indication does not prove that the drug is
particularly good. It proves only that it is better than
placebo. It does not prove that the drug won't kill you,
either. It only proves that the drug is safe according to
someone's notion of the relative safety of the drug
in comparison with the disease, taking into account a few other
factors.
Now Wellbutrin XL has an indication "for the prevention of seasonal
major depressive episodes in patients with a diagnosis of seasonal
affective disorder." It is the only drug that has that
indication. So now, the company can advertise it as being the
only drug approved for that
purpose. Notice that this does not mean it is the only drug
that works, nor does it mean that it is better than other drugs for
that purpose. Those things may or may not be true.
What the indication means, is that GSK went through the
expense, time, and trouble to get the FDA indication.
Understanding these things is an exercise in making distinctions, and
avoiding assumptions.
Continuing with that exercise, I would like to point out that I do not
mean to imply any criticism of either GSK, or Wellbutrin XL.
Both have a legitimate place in the world. I just
wish that the actions of the FDA were easier for the general public to
understand, and that journalists would do a better job explaining these
things.
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The same I said for chocolate:
http://scienceblogs.com/mixingmemory/2006/06/chocolate_on_the_brain_is_…
It may take the edge off of symptoms, it has nothing to do with the underlying cause.
BTW, I have SAD, but Wellbutrin gives me seizures of sorts.
The lay press has a penchant for sensationalizing and often distorting any medical information it can get its pens on, and psychiatric news is clearly an especially ripe target. In thegrand age of the Internet, where everyone's an expert, I imagine that half of your practice could be spent clarifying the "facts" reported in everyone's local rag over the AP wire.
Regarding your post last week that mentioned Intermittent Explosive Disorder and the blogger who noted that such people "used to be called assholes," I admit that this observation is eerily similar to what I first felt upon learning that personality disorders are, by definition, untreatable. As such they seem to be nothing more than labels.
P.S. You look very much like Dr. Lawrence Jacoby in your profile pic.
I suppose that it might help to try to educate the journalists more, but I get the impression that their eyes start to glaze over once you get into the difference between pharmacodynamics and pharmacokinetics.
Besides, when lay people write about science without understanding it, we call them journalists. When lay people write about science after reading and understanding it, they call us policy analysts. Unfortunately, if we tried to write a journalism-type article about whatever field we analyze, nobody would print it, because we're "biased insiders." Oy.
My name is Tricia Hurley and i would like to show you my personal experience with Wellbutrin.
I am 54 years old. Have been on Wellbutrin for 1 year now. Helps with depression. No weight gain like with Zoloft or decreased libido like with Prozac. I do think Prozac worked better and the only reason I went off it was my husband complained about that libido thing.
I have experienced some of these side effects -
Involuntary jerks of hands and legs. Feels like when you're about to fall asleep and suddenly jerk awake, but this is in the daytime. Often feel like adrenaline is flooding my stomach.
I hope this information will be useful to others,
Tricia Hurley