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Q: Would a Lower
Dose of Lamictal Reduce Risk during Pregnancy & Lactation?
I have Type II Bipolar
Disorder. I am on 200 mg Lamictal and have no symptoms or side effects.
Because a seizure medication controls my symptoms, is it possible/reasonable to
believe that a ketogenic diet would help control symptoms at a lower dose of
Lamictal?
I
understand that the (assumed) method that Lamictal works is by inhibiting
glutamate. If this is correct, could an MSG-free diet and choosing foods low in
glutamate control symptoms at a lower dose of Lamictal?
Would a
lower dose of Lamictal reduce risk during pregnancy and lactation?
Thank you!
Anne
Dear Anne – (sorry to be so slow in replying this
month)
Hmm, 200 mg, no symptoms, no side effects. Mighty
hard to beat that, with a medication with no known long term risks (lamotrigine/Lamictal).
However, if the questions arise because you’d like to consider pregnancy,
off we go --
1. Ketogenic diet: because
these diets can have anti-epilepsy effects, and
because some anti-epilepsy medications can help in bipolar disorder (but not all
of them), might such a diet help control bipolar symptoms? Of course, we’d also
have to wonder what effects such a diet might have on a developing fetus, and
compare that to the risks of lamotrigine; but first, to see if anyone has
studied effectiveness of this approach in bipolar disorder --
Searching ketogenic diet bipolar disorder
on Google, a reasonable place to start, oh look, there’s a letter I wrote on
this in
2004, first link after the Wikipedia link above.
Darn: I’d have hoped in 6 years there might be more on this subject. So, let’s
try PUB MED again, same procedure I outlined in the 2004 letter. No, nothing new
there (the letter from Dr. Belmaker to which I referred was published. They
tried the ketogenic diet in a patient with bipolar disorder, but it didn’t work;
however, they measured whether the patient actually became ketotic with her
diet, and found that she did not, so the theory didn’t get a fair trial.)
2. Could an MSG-free diet and choosing foods low in
glutamate control bipolar symptoms, perhaps allowing a lower dose of lamotrigine?
Well, again we’d have to wonder about the effects of such a diet on a developing
fetus. Perhaps they need a large supply of glutamate for building themselves? I
doubt that’s been studied well enough to reassure you. So again, you’re
comparing that unknown risk versus the known risks of lamotrigine in pregnancy,
which you’ve probably discovered are not very big, but apparently not quite zero
either, because of the recent finding of increased incidence of cleft palate and
other related disorders, occurring at a rate statistically greater than in
babies of women not taking lamotrigine.
Somewhere along the way here, although you didn’t ask
specifically about it, you’d also have to compare the risk to the developing
fetus of going without lamotrigine but potentially having your old bipolar
symptoms back, and the impact of those symptoms on the fetus – currently thought
to be a significant risk, at least for severe symptoms. And then there’s no
guarantee that going back on the same dose of lamotrigine will get you the same
outcome you’re getting now, if you go off then back on (not to mention the
common worsening in symptoms that occurs after a pregnancy; and is that
decreased by staying on an effective mood stabilizer through pregnancy and the
post-partum period? Again unknown. Why aren’t these things studied, you might
ask? Snide answer: because the gender ratio of medical students only recently
reached 50/50 (or close; in some schools the women outnumber the guys now).
That’s our next generation of researchers…
3. Lower lamotrigine dose, lower risk? That’s a short
answer: unknown again. It took years to find the small signal of risk in
pregnancy for lamotrigine; to dissect that signal and correlate it with doses
used – that’s another long wait. Because, you see, one needs big numbers even
just to find the signal, and the only numbers you can really count are women who
became pregnant while on lamotrigine and no other medications that might affect
risk. That’s a small number. Then you need much bigger numbers to correlate dose
(e.g. there might only be a very small number of women who were taking less than
100 mg, and most would be taking 200 or so).
Sorry, you ask very reasonable questions and yet most of
the answers boil down to “don’t know”, yet I’m also challenging you with other
tricky questions (and the answer to those is also “don’t know”!). Not fair.
Sorry that’s the state of things. You might be interested in the story of a
glutamate cousin, a related, similar amino acid, that’s been studied as a
glutamate opposite (perhaps a similar role as that played by lamotrigine…):
cysteine.
Good luck with your research and your decision-making.
Dr. Phelps
Published June, 2010
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