My doctor doesn't know. Anyone?

[broken4life]

So my doctor lowered my lithium from 900mg/day to 750mg/day because my test came back reading 1.1. So he lowered it to the 750, which I've been taking for 3 weeks and my blood levels came back at 1.2.
How is it possible for the level to increase when he decreased the dose. I tried to read online but can't seem to find anything solid.

Thanks to anyone who reaches out to this confused girl.

[paul m]

Hello Broken4life. Lithium levels depend on many things. Some of the more important things are 1) your weight, your metabolism , your kidney function, how you have been feeling and how long you've been taking lithium, when you took your last dose and how much fluid there is in your body.(most of what is below is my opinion and not scientific fact)

For example if I have been more active or been ill or had the runs, my lithium levels can soar due to the decreased water content in my body. Even a cold can shift my lithium levels.

Ideally lithium levels should be taken at exactly 12 hrs after I've taken my last dose, and my previous doses should all be taken exactly as prescribed, it's seldom possible to be this exact. I have found that many lab techs do not ask when I took my last dose and just mark down 12 hrs, even though it may have been only 5 or as much as 18hrs, it can make a big difference.

I've been taking lithium for a long time,but I've been peeing (pardon the expression) for even longer. I know that some days my urine output is higher than other days. I have no idea why, I can only assume that my kidneys on some days react slightly different to the food and drink that I consume. I don't put any salt in my food, so perhaps on the days that I eat in a restaurant (they often serve food high in salt) perhaps my body will retain more salt. Or perhaps they just react differently on some days. (our bodies get rid of lithium by way of our kidneys).

Alcohol and caffeine intake can also sharply affect lithium levels.

Lastly, my doc should also be testing my kidney function at the same time, not all docs order this test. Lithium can alter your kidney function and it is important that a basic kidney function test should be done every time you give blood for a lithium level test. (Its just a slightly different test done on the blood that you give).

For a slightly more scientific primer, https://en.wikipedia.org/wiki/Lithium_(medication) Take Care. paul m

[broken4life]

I don't think he is testing for kidney function at all. I mean I had not been feeling well for about 4 days prior to the test so maybe that had some affect on it it. But why would a psychiatrist NOT know answers to my very logical questions.
Thanks for all your input