When I first started to take lithium, I wanted to calculate my peak serum concentration using my 12-hour sample value. I knew it was going to be a very rough estimation, but for me, doing the calculation made me feel less anxious about toxicity.
My plan was to use the exponential decay formula to find the peak concentration (assuming the peak occurred around five hours). I wanted to find out, given I knew my serum creatinine levels, what my approximate lithium half-life was. I went looking for data in the lithium pharmacokinetic literature to figure this out.
This blog post is in reference to my article in the May 2023 edition of the Lancet Psychiatry – Lithium Story: Eight Guidelines, Eight Recommendations. It is adapted from notes I sent to one of the editors when constructing the article
In a previous blog post, I looked at two examples of imprecise language in a Grandjean and Aubry paper about lithium pharmacokinetics (which I used in my May 2023 Lancet Psychiatry article). In this post, to show that the problem is not limited to a single paragraph in a single review paper, I have included a couple more examples of unclear messaging.