lithium carbonate treatment of manic episodes of manic-depressive illness. initiate treatment at 600-900 mg/day in 3 divided doses; increase to 1,200-1,800 mg/day in 3 divided doses to achieve serum lithium concentrations between 0.8 and 1.2 mmol/l. adjust dose according to clinical response and trough serum level (12 h) after steady state is reached (4-5 days). after the acute manic episode subsides, adjust dose to maintain a level of 0.6-1.0 mmol/l. the average dosage range at this stage is usually 450-1,200 mg/day. if a satisfactory antimanic response is not obtained in 14 days, consider discontinuing lithium. once patients are stabilized on a maintenance dose with a multiple dosing schedule and once stable therapeutic blood levels are reached, consider a once-daily dosage regimen. the total daily dose, when given as a single dose, may be about 5-30% lower than when given in divided doses over the day.