Q: Lamotrigine & Melanin : Beta-blockers &
Bipolar Disorder Treatment
Dr. Phelps, I have two
questions in regard to mood stabilizers or potential mood stabilizers: 1) Does Lamotrigine permanently bind to melanin receptors or does it clear out after a
certain length of time? 2) I have seen Beta-blockers listed as potential
treatment options for bipolar in some publications. Apparently, the theory is
that these increase blood flow to the frontal lobes. Are these worth a try?
1. Let's start with the beta blocker. I think what you may have run into,
unless there is something out there I haven't seen yet, is that beta-blockers
have been used as an augmentation strategy along with standard serotonergic
antidepressants for the treatment of unipolar major depression. Their
effectiveness in this role has been debated for some time. The current working
impression is that they don't have much impact. Interestingly, in response to
your question, I discovered one article on the use of beta-blockers in bipolar
disorder, suggesting that they might actually have an adverse effect (Yatham
et al; I have not dug up the article itself to see what adverse
effect they are referring to).
Whoops, hold it, maybe this is the article that spurred your question. In
February of 2008, in a European Journal, a
group reported augmentation of
paroxetine (trade name Paxil in the United States) with a beta blocker (pindolol).
Although again they did not find that overall this augmentation strategy was
more effective than a starting up paroxetine alone, the combined strategy
(versus paroxetine plus placebo) did indeed help patients with bipolar
In other words, in this 2008 study, some of the patients had bipolar depression,
and some had unipolar depression. In those with bipolar depression, when they
were given paroxetine, they did better if paroxetine was combined with pindolol
than if paroxetine was given alone. Well, that's interesting. At this point,
adding paroxetine for the treatment of bipolar depression is not a widespread
strategy. So this paper may not have a great deal of impact (particularly in the
United States, where a much larger scale study recently showed that paroxetine
was no better than a placebo in patients with bipolar disorder (Sachs).
2. As for lamotrigine and melanin: nothing new -- I just looked, on Google and
Pub Med -- since I wrote a
response to a question about that in 2005.
I presume that because there is still a one-liner about this on websites like
Drugs.com, the issue keeps coming up. But there is really nothing to go on to
substantiate concern about this possible connection. As far as I know, the only
place that any warning at all was raised about it is in the manufacturer product
information. As far as I can tell, that is what drugs.com is quoting. If you
know of any other source of information on this issue, please
let me know.
Published November, 2008