Lithium levels; Depakote and Lamictal Question

All three of the above meds are used for bipolar disorder but, to my knowledge, only Lithium is checked (via blood tests I'm assuming?) for correct levels. I periodically have a liver function test for the Depakote, but is there something different about Lithium that periodic level checks are needed vs the other two?

Thank you for any info on this!

Lithium is toxic to the kidneys if blood levels get to high, so it must be carefully monitored. It can lead to renal failure, i.e. dialysis or transplant.

If you stick to therapeutic levels, this is not (that I know of) an issue.

The reason you have to have Lithium levels checked regularly is to ensure you don't have a toxic level of Lithium in your system. Lithium toxicity can be as mild as a stomachache or as serious as kidney or liver damage/failure. I've been on Lithium for almost a year now, and I get bloodwork done every three months. The only thing I have to be careful of is to not over exert myself, because getting overheated can cause you to go toxic as well.

Depakote can affect the kidneys and liver as well, but not to the extent of Lithium. When I was on Depakote, I think I only had one blood draw in 6 months, and that was at 6 weeks to make sure the dose was proper.

As far as Lamictal, that was one I was never prescribed. I've been given pretty much everything under the sun until I was properly diagnosed bi-polar, and Lithium is my miracle drug.

Both lithium and Depakote (valproate) are designated NTI (Narrow Therapeutic Index) drugs. So is Tegretol (cabamazepine).

Therapuetic index is the ratio of the toxic dose to the therapuetic dose. The therapeutic index for lithium is less than 2, which is to say there is not a huge difference between the blood concentration that stabilizes mood, and the toxic dose that damages your tissues.

Ideally, routine blood concentration assessments should be done for all three of these mood stabilizers. It can be done by checking for toxic effects (e.g. liver enzyme concentrations), but that is indirect assessment.

The way a person's body manages lithium ion (the dissolved lithium atoms) can change over time. It is important to catch those changes early, before they become toxic changes. The same goes for valproate.

Lar

{{{{Samsara, Dolfin, Larry}}}}

Thanks so much for the explanation...I understand more why Lithium needs checked. Makes me wonder, though, why my pdoc isn't concerned about the Depakote. I've been on it for 10+ years. I liver function test was done after I'd been on it about 6 weeks (pdoc said IF my liver was affected at all, it usually shows up shortly after beginning the med). Since then, I request one at least once a year. My pdoc gives me the impression he thinks I'm over-reacting, but I'd rather be on the safe side.

Related question: When your pdocs prescribe a new med for you, do they discuss any possible side effects? Mine doesn't - guess he figures I'll read the insert with the meds.