Lithium monitoring: should tracking prescriptions be implemented to improve outcome? An evaluation of potential practice change

This study seeks to compare rates of blood lithium monitoring with rates of lithium prescription collection in order to evaluate whether identifying patients with low frequency of monitoring could alert clinicians to poor prescription collection. It examines whether routine monitoring of lithium prescription pick‐up would be likely to reduce admissions to hospital, as a way of identifying those who were poorly adherent with treatment. It also ascertains the frequency of lithium toxicity and its outcomes.

The frequency of monitoring of lithium was assessed through laboratory results of 773 patients. A sub‐sample of 119 patients on lithium was found through general practice records and the rates of medication collection determined. Admission data were examined to assess whether this was related to a failure in blood monitoring or prescription collection.

A total of 87 per cent of the GP group had lithium levels measured at least twice a year and 84 per cent collected more than 80 per cent of prescriptions. It was found that those patients not collecting their prescriptions were a different group from those who did not have their blood levels monitored. Admission rates were not higher in those who were less efficient at picking up prescriptions. Two per cent of the total sample had lithium levels above 1.6 mmol l⁻¹. There were no fatalities associated with high levels.

It is important to assess the real potential benefits of additional monitoring rather than assuming that increased surveillance will improve the outcome.