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Q: Lamictal Dosing
I have been diagnosed with rapid cycling bipolar while living in Japan. Dealing
with doctors in another language has been an enormous struggle. Many of the
medications available in the US are not available here, and nothing I tried
worked (except to cause massive weight gain). I am able, under Japanese law, to
import my own medicines, which I have. I am slowly (12.5 mg a week) dosing
myself with Lamictal, with some benefit. I have now reached 50mg. The
problem is that the doctors here have no experience of using Lamictal, they
don't know what dose I should go up to and are recommending that when I feel a
bit better I should lower the dose down to 25mg. This is the only drug I am on
(except for fish oil, sleeping tablets and voltaren for a disc problem). I am
extremely worried that they are just making a wild guess, since I thought I had
to keep taking it long-term if it helps, and at a higher dose than that. Please
help, as I have no other English speaking support.
Thank you.
Dear Vivienne --
It is not our general practice to lower lamotrigine if it works. We generally,
for this medication anyway, follow the maxim "what gets you better keeps you
better" (not a universal rule). I can't step in and "play doctor" at this
distance, so you need to keep chasing options for who's going to help you manage
this situation. But I can agree that the current dose is relatively low. I've
seen some people start to show improvement at 25 mg, and 50 mg has been shown to
be better than placebo (that is to say, we know from randomized trials that 50
mg is an effective dose -- not just clinicians saying excitedly that they have
seen it work). I used to stop the dose increase as soon as the patient was
getting better, but some of the researchers who have studied this stuff have
strongly suggested "get to 200", thinking that this offers more preventive
benefit against return of symptoms.
So if your mood history has been "recurrence", then
there is reason to think preventively (if not, I can imagine this "lowering
strategy", though only after a long while of things going smoothly).
In my experience, few patients have any side effects as
they go from 100 to 200 if they didn't have them already (mainly headache, which
can limit the dose for some people, although after a few months during which we
lowered the dose to avoid this problem, some people have been able to go up
without the headaches coming back). So if there is additional benefit to be had
at 200 and no "price" to pay (other than the real price of the medication, which
as you know ain't cheap), this logic does seem rather compelling. I discuss it
with my patient and we decide. But I have very few people hanging out at less
than 100 mg (unless they're also taking Depakote, which roughly doubles the
blood level and thus can make 50 mg more like 100).
That may give you some idea of the range and the logic
behind dosing. I think these are very standard here in the U.S., i.e. not just
my practices, from discussion with colleagues. I hope you're able to arrange
some "stateside" consultation system soon.
Dr. Phelps
Published October, 2005
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