Pharmacogenetic characteristics of the eosinophilia‐myalgia syndrome

David A. Flockhart, Daniel J. Clauw, Elaine Buchert Sale, Jan Hewett, Raymond L. Woosley

Research output: Contribution to journalArticle

26 Scopus citations


This study tested the hypothesis that patterns of xenobiotic metabolism in patients with eosinophiliamyalgia syndrome (EMS) differed from healthy control subjects. We determined the genotypes of 27 EMS patients with EMS and 114 control subjects for the cytochrome P450 CYP2D6 polymorphism. The metabolic phenotypes of patients with EMS for S‐mephenytoin hydroxylation (n = 17) and dapsone acetylation (n = 19) were determined and compared with 29 healthy control subjects. The incidence of the CYP2D6 poor metabolizer genotype (mutant/mutant) was 0.185 in patients with EMS and 0.061 in control subjects (Mantel‐Haenszel, χ2 = 7.213, p = 0.007). The mephenytoin S/R ratios were 0.39 ± 0.23 in patients with EMS versus 0.18 ± 0.13 in control subjects (p≤ 0.005). There was no difference in dapsone acetylation between the two groups. A pattern of xenobiotic metabolism may play a role in the pathogenesis of EMS, but the precise role that it plays remains unclear. Clinical Pharmacology and Therapeutics (1994) 56, 398–405; doi:

Original languageEnglish (US)
Pages (from-to)398-405
Number of pages8
JournalClinical Pharmacology & Therapeutics
Issue number4
StatePublished - Oct 1994

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

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    Flockhart, D. A., Clauw, D. J., Sale, E. B., Hewett, J., & Woosley, R. L. (1994). Pharmacogenetic characteristics of the eosinophilia‐myalgia syndrome. Clinical Pharmacology & Therapeutics, 56(4), 398-405.