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Q: Does Lithium Lose it's Effectiveness after Long Term Use?
Would Lithium & Carbamazepine Stay Effective?
She was diagnosed approx. 13 years ago at age 32 and has been on Lithium. She
has experience 3 manic episodes in the past 16 months. Does Lithium lose it's
effectiveness after long term use and what would the longer term
outlook be now that carbamazepine has been added. Does this combination stay
effective.
Thanks
Larry
Dear Larry --
Many medications for bipolar disorder seem to lose their effectiveness over
time, sometimes much more quickly than this, although I've always thought of
this phenomenon as the bipolar disorder getting worse, rather than the
medication getting weaker. For example, when this kind of worsening takes place,
people often are having symptoms that are worse than they've ever had (whereas
with the medication-weakening explanation, we'd expect the return of previous
symptoms, but not worse, right?) Not all bipolar disorders worsen this
way, only some.
One theory about this is that each mood episode can
make subsequent episodes more likely and more severe (this is called the
"kindling" model, a term borrowed from epilepsy where the same phenomenon is
seen (in some versions of epilepsy, it appears that each seizure can make
subsequent seizures more likely and more severe). Although this is a theory, it
does tend to make at least some of us doctors want to try to keep any episodes
from happening at all, not just because episodes can be bad unto themselves, but
also because they might make subsequent episodes more likely.
This often leads us to combinations of medications such
as your spouse/SO is currently taking. Will this too "stop working"? I can't
say. In general the trick is to look for very subtle signs of cycling, and if
those are seen, turn up the mood stabilizer -- in accordance with the above
theory. That's how I do it, but as noted, this is just a theory. I heard an
experienced doc' ask the other day whether we shouldn't just wait around for the
next episode and then treat it, rather than having people on things like lithium
for years trying to prevent episodes that might be almost decades apart. Or does
that make progression such as your spouse/SO has experienced more likely? We
don't know.
I hope this combination "sticks". Good luck to you
both.
Dr. Phelps
Published December, 2005
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