Phenytoin and plasmapheresis: Importance of sampling times and impact of obesity

Keith M. Olsen, Michael A. Marx, Michael S. Monaghan, Edilissa Barnes, Bruce H. Ackerman, Alex A. Pappas

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The effect of plasmapheresis (PP) on total and free phenytoin clearance is reported. An obese patient with the diagnosis of thrombotic thrombocytopenic purpura (TTP) was treated with PP. Twelve episodes of PP, having exchange volumes of 1.5–2.25 times the plasma volume with a mean ± SD 7.7 ± 0.8 L of plasma removed, were studied. A significant (p < 0.05) difference was observed with a mean change in plasma phenytoin concentrations from pre- to end-PP of 7.32 ± 2.5 mg/L compared to 1.98 ± 0.7 mg/L observed pre-PP to 1 h post-PP. These values corresponded to 48.4 ± 11.6 and 15.0 ± 6.7% decreases in phenytoin concentrations at the two aforementioned time periods. To prevent misinterpretation of plasma phenytoin concentrations, samples should not be obtained for at least 2 h after PP.

Original languageEnglish (US)
Pages (from-to)624-628
Number of pages5
JournalTherapeutic Drug Monitoring
Volume16
Issue number6
DOIs
StatePublished - Dec 1994

Fingerprint

Plasmapheresis
Phenytoin
Obesity
Thrombotic Thrombocytopenic Purpura
Plasma Volume

Keywords

  • Free phenytoin
  • Phenytoin
  • Plasmapheresis

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

Cite this

Olsen, K. M., Marx, M. A., Monaghan, M. S., Barnes, E., Ackerman, B. H., & Pappas, A. A. (1994). Phenytoin and plasmapheresis: Importance of sampling times and impact of obesity. Therapeutic Drug Monitoring, 16(6), 624-628. https://doi.org/10.1097/00007691-199412000-00017

Phenytoin and plasmapheresis : Importance of sampling times and impact of obesity. / Olsen, Keith M.; Marx, Michael A.; Monaghan, Michael S.; Barnes, Edilissa; Ackerman, Bruce H.; Pappas, Alex A.

In: Therapeutic Drug Monitoring, Vol. 16, No. 6, 12.1994, p. 624-628.

Research output: Contribution to journalArticle

Olsen, KM, Marx, MA, Monaghan, MS, Barnes, E, Ackerman, BH & Pappas, AA 1994, 'Phenytoin and plasmapheresis: Importance of sampling times and impact of obesity', Therapeutic Drug Monitoring, vol. 16, no. 6, pp. 624-628. https://doi.org/10.1097/00007691-199412000-00017
Olsen, Keith M. ; Marx, Michael A. ; Monaghan, Michael S. ; Barnes, Edilissa ; Ackerman, Bruce H. ; Pappas, Alex A. / Phenytoin and plasmapheresis : Importance of sampling times and impact of obesity. In: Therapeutic Drug Monitoring. 1994 ; Vol. 16, No. 6. pp. 624-628.
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