Retrospective Audit of Serum Carbemazepine Level Monitoring at The Canberra Hospital
Background: Therapeutic drug level monitoring for antiepileptic drugs (AED) has a limited role in clinical practice. Inappropriate and unwarranted use of AED level monitoring is common, despite the limited usefulness of this test as found in previous studies.
Aim: To assess the current practice of serum carbamazepine (CBZ) level measurement at The Canberra Hospital (TCH) and its effect on patient management.
Methods: An audit was conducted on all of the CBZ level measurements performed on inpatients at TCH from 1st October to 31st December, 2006. Requests for measurement were considered appropriate or inappropriate on the basis of their indication and timing according to published guidelines.
Results: Forty-nine CBZ level measurements were recovered. Of these, 45% had an appropriate indication and were sampled correctly. Forty-eight percent of the 29 relevant samples were not taken at an appropriate time. The results of 51% of the tests were not documented in the patients’ medical records. Only 10% of CBZ level measurements were clearly associated with a change in patient management.
Conclusions: Compared with a recent similar audit of serum sodium valproate level measurement, a considerably higher proportion of CBZ level measurements were appropriate and valid. Potential reasons for this and possible ways in which the situation might be improved still further will be discussed.