Lithium-related medication problems on nonpsychiatric inpatient medical units

PURPOSE: Results of a study of medication-related problems (MRPs) associated with lithium use on nonpsychiatric inpatient medical units are reported. METHODS: In a single-center, retrospective study, the records of all patients hospitalized over a 21-month period who received lithium or had a documented serum lithium concentration during hospitalization were evaluated. The primary objective was to identify patient-specific factors associated with lithium MRPs on nonpsychiatric inpatient medical units. Secondary objectives included characterization of lithium MRPs. Identified MRP occurrences were further evaluated to determine if an intervention was necessary to resolve the MRP and whether or not an intervention was made. RESULTS: A total of 150 patients were included in the study sample. One or more lithium MRPs were identified in 85% of the patients, with a total of 255 lithium MRPs identified. None of the patient-specific factors analyzed were significantly associated with MRP occurrence. Of the 128 patients in whom a lithium MRP occurred, 92.2% (n = 118) were judged to be appropriate candidates for interventions as defined per the study definitions; among those 118 patients, such interventions were documented for only 40.7% (n = 48). CONCLUSION: Lithium MRPs were found to have occurred frequently on nonpsychiatric inpatient medical units at 1 hospital. Laboratory test- related MRPs and drug-drug interactions were the most commonly identified types of MRPs. Interventions to address MRPs were not made in the majority of patients; however, interventions were more frequently made when psychiatry consultation was involved.