The Role of Serum Lithium Concentration on Pill Burden in Psychiatric Populations

Objective: Current research validates the use of lithium as a first-line agent in bipolar disorder, yet it remains underutilized. This might, in part, be the result of lithium's risk of toxicity. A lower serum lithium concentration would decrease the risk of toxicity. This study examined whether lithium serum concentrations are associated with an additional medication burden resulting from psychiatric polypharmacy. Methods: The retrospective data of adult inpatients receiving lithium who had at least one serum lithium concentration recorded were extracted from the computerized patient record system, bar code medication administration, and mental health automated health record system. Results: 38 patient charts were reviewed and a total of 192 individual serum lithium concentrations were analyzed. There was no statistically significant difference (increase or decrease) in the number of psychiatric medications prescribed or the number of scheduled psychiatric medication doses administered. There was a statistically significant increase in the number of psychiatric medications prescribed over the Food and Drug Administration (FDA) recommended maximum daily dose (MDD) following a serum lithium concentration record. Individuals with a serum lithium concentration below 0.6mEq/L were more likely to be prescribed medications over the MDD. Conclusion: Serum lithium concentrations did not increase or decrease the overall psychiatric pill burden. The number of psychiatric medications an individual is prescribed remained the same regardless of their serum lithium concentration. Overall pill burden did not change with the serum lithium concentration; however, lower serum lithium concentrations might necessitate prescribing of psychiatric medications in doses exceeding the MDD.