Standards of laboratory practice: antiepileptic drug monitoring

¹ Departments of Pathology and Laboratory Medicine and
² Neurology, University of Cincinnati Medical Center, P.O. Box 670714, Cincinnati, OH 45267-0714.

³ Division of General Medicine and Primary Care, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115.
^a Author for correspondence. Fax 513-558-2276; e-mail ann.warner{at}uc.edu.

Discussion and development of standards for appropriate monitoring led to the following key recommendations for ordering, sampling, and analyzing antiepileptic drugs: Monitoring should usually be done on trough specimens after steady-state has been reached and always with an appropriate medical indication; non-steady-state concentrations may be indicated in selected situations. Monitoring of free phenytoin and free valproic acid is indicated in specific situations and should be done in serum. The metabolite of primidone, phenobarbital, should be measured concurrently with parent drug, but the active metabolite of carbamazepine does not need to be monitored unless the patient is exhibiting an unusual toxic response that cannot be otherwise explained. Assays used for antiepileptic drug monitoring should display a long-term CV of <10% and preferably <5%. Subtherapeutic and supratherapeutic drug concentrations should be investigated on a regular basis as part of a quality assurance process.

The following articles in journals at HighWire Press have cited this article:

				U. Idrees and M. Londner Pharmacotherapy Overview of Seizure Management in the Adult Emergency Department Journal of Pharmacy Practice, October 1, 2005; 18(5): 394 - 411. [Abstract] [PDF]

				R. W. Jenny and K. Y. Jackson-Tarentino Causes of Unsatisfactory Performance in Proficiency Testing Clin. Chem., January 1, 2000; 46(1): 89 - 99. [Abstract] [Full Text] [PDF]