Lithium 150 mg. Lithium (Eskalith ® , Eskalith CR ® , Lithobid ®) is a medication used for the treatment of bipolar disorder. It is available by prescription only and comes in several different forms and strengths, including:1  Lithium carbonate 150 mg capsules. Lithium carbonate 300 mg tablets. 2  Lithium carbonate 300 mg extended-release tablets (Lithobid). 3  Lithium carbonate 450 mg extended-release tablets (Eskalith CR). 4  Lithium citrate syrup, containing 8 mEq lithium per 5 mL, which is equivalent to 300 mg lithium carbonate per 5 mL or per teaspoonful.