IV fosphenytoin in obese patients

Sarah L. Clark, Megan R. Leloux, Ross A. Dierkhising, Gregory D Cascino, Sara E. Hocker

Research output: Contribution to journalArticle

Abstract

Background: Previous studies evaluated the disposition of IV phenytoin loading doses and found that obese patients had increased drug distribution into excess body weight, larger volumes of distribution, and longer half-lives when compared to their nonobese counterparts. We assess the safety and efficacy of fosphenytoin loading doses in patients with different body mass indices (BMIs). Methods: A retrospective chart review was conducted in 410 patients who received fosphenytoin. Patients were divided into 2 groups: BMI <30 (nonobese) and BMI ≥30 (obese). Patient demographics, fosphenytoin dose administered in mg/kg body weight, renal and liver function tests, fosphenytoin drug levels, and pre- and post-fosphenytoin administration vital signs were collected to assess for adverse events. Necessity of additional antiepileptic loading doses was used as a surrogate for clinical efficacy. Results: The median dose of fosphenytoin administered was 19 mg/kg (interquartile range 15-20). The most frequently encountered adverse event was hypotension, which occurred in 39% of the cohort. Using a Bonferroni adjustment for multiple comparisons, there were no differences in adverse events between the 2 groups. The need for additional antiepileptic loading doses was not different between the 2 groups (p = 0.07). Conclusions: The incidence of adverse events and the need for repeat loading antiepileptic medications was similar between the 2 groups. From our findings, the patients in our study did not receive empiric loading dose adjustments and the current method of loading fosphenytoin achieves similar outcomes, regardless of the patient's BMI.

Original languageEnglish (US)
Pages (from-to)45-52
Number of pages8
JournalNeurology: Clinical Practice
Volume7
Issue number1
DOIs
StatePublished - Feb 1 2017

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Body Mass Index
Anticonvulsants
Body Weight
fosphenytoin
Vital Signs
Liver Function Tests
Phenytoin
Pharmaceutical Preparations
Hypotension
Demography
Kidney
Safety
Incidence

ASJC Scopus subject areas

  • Clinical Neurology

Cite this

Clark, S. L., Leloux, M. R., Dierkhising, R. A., Cascino, G. D., & Hocker, S. E. (2017). IV fosphenytoin in obese patients. Neurology: Clinical Practice, 7(1), 45-52. https://doi.org/10.1212/CPJ.0000000000000322

IV fosphenytoin in obese patients. / Clark, Sarah L.; Leloux, Megan R.; Dierkhising, Ross A.; Cascino, Gregory D; Hocker, Sara E.

In: Neurology: Clinical Practice, Vol. 7, No. 1, 01.02.2017, p. 45-52.

Research output: Contribution to journalArticle

Clark, SL, Leloux, MR, Dierkhising, RA, Cascino, GD & Hocker, SE 2017, 'IV fosphenytoin in obese patients', Neurology: Clinical Practice, vol. 7, no. 1, pp. 45-52. https://doi.org/10.1212/CPJ.0000000000000322
Clark, Sarah L. ; Leloux, Megan R. ; Dierkhising, Ross A. ; Cascino, Gregory D ; Hocker, Sara E. / IV fosphenytoin in obese patients. In: Neurology: Clinical Practice. 2017 ; Vol. 7, No. 1. pp. 45-52.
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