Lithium Serum Levels

[AnneMarie]

I was on 900mg of Lithium for some time with a blood serum level of .7. My pdoc raised it to 1200mg a few weeks ago, and my test came back 1.2, a five point increase when I'd been trending at just over three. I'm getting another draw next week to see if the lab screwed up, which would make some sense since I'm not having any side effects. My pdoc wants me at no higher than 1.0.

My questions are:

Are there a lot of things that can cause such a big change?

Has anyone had wild swings in serum levels?

[resonance]

Not enough water or not enough salt can push people into toxicity. Have you made any changes to your diet recently?

[AnneMarie]

Not enough water or not enough salt can push people into toxicity. Have you made any changes to your diet recently?

No, not really. I don't have any side effects, so I know that I'm not experiencing toxicity. I'll try more water. I can't remember if I had much that morning.

[Silver]

The dose/level relationship isn't a straight line. (300 mg does not automatically equal .X SL as the dose increases.)

It will take a steeper curve up for some people as the dose goes up. This is where those 150 mg caps come in very handy. It's also why it's standard to recheck the level 4-7d after a dose change.

SL will vary somewhat with mood state. It goes down with mania in some (and then goes up as mania remits - that's a problem.) It goes up with depression. It's something of a mystery. It's not just that we're racing around dancing all night or laying on the couch and that clearance is increased by increased activity, fluids, etc. I can't look it up right now - will try to look it up tomorrow - but the article I'm thinking of was Goodnick and ??Schor, early 1990s. I have it at the office.

Did you change formulations? I doubt it, you'd have said so.

And are you taking your whole dose at once, or are you splitting it? If you're splitting it, when did you take your morning dose, and when was the lab? Times, please.