Q:  Lithium & Thyroid Meds

I have been in treatment since 1991  I have taken a host of meds over the years as they seem to loose effectiveness after a few years.  I recently changed my Dr. and he started me on Lithium Carbonate (time release).  After 3 months I am taking 1200mg, blood level at 0.8.  Wow, it has really squashed the manic phases!! Such peace.  BUT, now my thyroid is acting up, and I am experiencing a "depression" I am not familiar with.  Lack of desire, sad, cry easily, feeling "dummbed down".  He wants to add Lamictal for the depression but I am just learning about how lithium affects the thyroid as well as how thyroid affects bipolar and how hypothyroidism contributes to depression.  I hesitate to do the Lamictal because I want to take care of my thyroid first.  Maybe Lithium is wrong for me?  If lithium screws up your thyroid, taking thyroid therapy seems like it will doom my thyroid in the long run.  I'm scared, The lithium really fixed the manic highs but it sounds like the side effect is dangerous to my thyroid as well as this new depression I am experiencing.  Used to be my depressive episodes followed a crash from a hi, this new depression is all the time and getting deeper.  My Dr is not hearing my concern over my thyroid, my General Practice (GP) Dr found the thyroid thing in a coincidental annual physical.  She wants to treat it with Levothroxine (I am taking it now-2 wk) but I am worried its a band-aid to a bigger problem-the lithium.  What do people do normally in this situation?  Will this damage my thyroid?  I need help quick, please email back....thanks.


Dear Mr. H' -- 
Your concern about the band-aid approach is understandable.  So it might help to know that this band-aid has been used successfully for several decades, that is, adding thyroid when lithium is the basis of the low thyroid in the first place -- rather than stopping the lithium. So, we know that much: it works. If someone has responded well to lithium and for some reason she/he and her/his doctor want to keep the lithium going, rather than switch to an alternative, then we routinely apply this band-aid and get good outcomes. As you've likely been assured, the chances of doing harm with the thyroid in this role are very low, so although it's a band-aid, at least it doesn't then generate its own problems (except for having to get the dose dialed in right, which can take awhile, and requires several blood tests, though you'd want at least half those blood tests to be checking your lithium level at this stage (more tests early, fewer later when everything is settled)). 

But, there's that second question in the background: what will this do to your thyroid in the long run?  The standard answer for years, the one I was taught, is that when the lithium is stopped, for whatever reason, your thyroid will bounce back to normal.  For most people, especially men, I think that's actually true.  There are some people, however, mostly or perhaps entirely women in my experience so far, who do not seem to pop back to normal thyroid function after lithium. I just recently came across an article on this corroborating this concern, suggesting that the presence of "antithyroid antibodies" might mark people who could end up hypothyroid, but that these antibodies are not consistently associated with this risk and so may not be of use for finding these people in advance.^Kirov  Yet that issue was not the main point of the article, which was just looking at the patterns of lithium effects on thyroid function.  The point of all this is that lithium effects on thyroid are still being actively investigated (albeit slowly, as there are no Big Bucks to fund this kind of research). I've never seen a paper reporting the frequency of people remaining hypothyroid after lithium made them that way and then was stopped.  Such data would help address your concern.  

Overall, of course, you'd want to weigh the risk of becoming permanently hypothyroid (even without lithium) and therefore having to take thyroid replacement for the rest of your life (and the probability of that event, which as explained above we can't give you, but we can say that it is uncommon if it occurs at all, and you're at lower risk than average because of your gender); versus the symptoms the lithium may help control.  Tricky, isn't it. I hope this helps just a little in that respect. 

Dr. Phelps 
 

Published November, 2005