Lithium treatment: prescribing and monitoring habits in hospital and general practice.

OBJECTIVES: To define current clinical practice of lithium prescribing and monitoring and to compare hospital based practice with general practice. DESIGN: Prospective study of doctors' practice. SETTING: Psychiatric hospital day and outpatient facilities and general practices in Edinburgh and Midlothian district (population 600,000). SUBJECTS: 458 patients taking lithium who had been stabilised and who remained as outpatients during the year of study. 219 were treated by their general practitioner and 190 by the hospital; 49 had shared care or care transferred during the study. MAIN OUTCOME MEASURES: Daily dose, duration of treatment, psychiatric diagnosis, mean annual serum lithium concentration, frequency of occurrence of and response to raised serum concentrations. RESULTS: Compared with hospital doctors general practitioners were more likely to prescribe lithium three or more times daily (43/219 (general practice) v 10/190 (hospital); chi 2 = 18.6, p = 0.001) and to estimate serum concentrations less frequently (4.5 v 5.3 measurements/year; t = 3.04, p = 0.003), and their patients were more likely to experience raised lithium concentrations (39/219 v 17/190; chi 2 = 6.8, p = 0.01). One third of doctors made no response to raised lithium concentrations in the next six weeks. CONCLUSIONS: General practitioners and hospital doctors care for similar types of patients and the stringency of lithium surveillance varies greatly among doctors. Certain aspects of practice give cause for concern and could be improved by following more uniform guidelines.