Q:  Gabapentin & Lithium as a Med Combo

I have run into problems with reactions to medications.  I started noticeable hand tremors from Lithium so we started taking me off it and withdrew too much too fast and I went into hypomania.  We then tried carbamanzapane and I am ok at 50mg. but have increased effect when using pain killers at increased dosage so we decided to try lamotrogine.  I developed a rash and my hair started to come out so  had to go off of that. 

We decided to stay with 300 mgs. of Lithium at night. 400 mg. of Gabapentin morning and dinner and 600 mgs. at bedtime.  I also take effexor 150 mgs morning and evening and 150 mgs. trazadone in the evening.

Its quite a cocktail and I am still on the edge of hypomania and going broke from my spending.  I think I will have to go up 150 mgs. in my Lithium and put up with the tremors as those side effects are probably the least cumbersome.

QUESTION
It was mentioned to me that Gabapentin and Lithium are not a good combination.  DO YOU HAVE ANY INFORMATION ON THAT?


Dear Ms. B' --
I ran that pair on a standard drug-interaction check (http://www.drugdigest.org/DD/Interaction/ChooseDrugs ); no interactions listed. One hears of lithium-anticonvulsant interactions, especially with carbamazepine for example, so I think there might be a sort of "hearsay" or "buzz" level concern that is not in the literature as such; or it might be better known than this and I've just not run into it.  

A PUB MED search (here's how to do one yourself) on gabapentin lithium interaction yielded one article by Frye and colleagues which looked specifically for a problem if these two medications were used together, as they are both excreted by the kidney -- but they did not find a basis for concern on the basis of how the kidney clears out these medications (they were not investigating any other aspect of how the medications might interact -- such as in the brain!). 

Dr. Phelps

Published Sept., 2006