Most agree that in order to achieve the desired effects of lithium without heading into a toxic range, the blood levels should be between 0.8 meq/Liter to 1.0 milli equivalent/Liter, Possibly higher (1.2-1.4) when treating someone in an acute manic episode. This range is referred to as the therapeutic window. Below these levels the incidence of relapse goes up, and above these levels people experience worsening side effects.
For some, even the 0.8 meq/liter may leave them with bothersome side effects, and so during periods of stability they, and their prescribers, may try to maintain symptom control at a lower level. Should symptoms begin to worsen, then dosage is increased.
Most people will be maintained on between 900–1200mg of Lithium a day, divided into two doses. The actual dose is individualized and followed by obtaining lithium levels. Occasionally, when treating someone in an acute manic state, the dosage might be increased to a maximum of between 1800–2100mg/day. This is then reduced as the person improves.