Accuracy and safety of a priori lithium loading.

A 30 mg/kg loading dose of slow-release lithium carbonate (Lithobid) was given in three divided doses to 38 patients to evaluate the accuracy and safety of achieving a therapeutic level in 12 hours. No patient experienced any adverse effects during the loading procedure or in the 12 hours after loading was completed. Prediction error (actual minus predicted level) for males was -0.11 mEq/L +/- 0.03 (SEM) with a mean absolute error of 0.16 mEq/L +/- 0.09 (SEM). Prediction error for females was -0.04 mEq/L +/- 0.07 (SEM) with a mean absolute error of 0.28 mEq/L +/- 0.14 (SEM). Lithium loading is safe and slightly overestimates the level actually achieved, except in obese females.