Phenytoin and fosphenytoin: A model of cost and clinical outcomes

We developed a pharmacoeconomic model to compare costs and clinical outcomes of administering phenytoin and fosphenytoin alone and in combination in hospitalized patients. Effectiveness data were obtained by distributing a questionnaire to 33 registered nurses at three acute care hospitals who worked in critical care, neurology services, or emergency department. The questionnaire addressed methods of phenytoin and fosphenytoin administration, frequency of adverse reactions, methods of treating adverse reactions, and demographic information. The model estimated that if 50% of phenytoin loading doses were substituted with fosphenytoin, a reduction in adverse events resulted in an estimated increase of $36/patient cost to the hospital. If phenytoin maintenance dosages were substituted with fosphenytoin, the model predicted essentially no change in cost to the hospital. It appears that fosphenytoin reduces adverse events at a reasonable increase in total hospital costs.