It is the shape and size of the tablets that is the problem. Lithium and mirtazapine look the same. I don't want to overdose on mirtazapine. I just have to be on the ball when I take my meds.The lozenge shape mirtazapine are the best and are larger than the lozenge shape mirtazapine. I just have to be on the ball when I take my meds.