title: Saint John's wort, an herbal inducer of the cytochrome P4503A4 isoform, may alleviate symptoms of Willis-Ekbom's disease.
abstract: OBJECTIVE
  Certain drug classes alleviate the symptoms of Willis-Ekbom's disease, whereas others aggravate them. The pharmacological profiles of these drugs suggest that drugs that alleviate Willis-Ekbom's disease inhibit thyroid hormone activity, whereas drugs that aggravate Willis-Ekbom's disease increase thyroid hormone activity. These different effects may be secondary to the opposing actions that drugs have on the CYP4503A4 enzyme isoform. Drugs that worsen the symptoms of the Willis-Ekbom's disease inhibit the CYP4503A4 isoform, and drugs that ameliorate the symptoms induce CYP4503A4. The aim of this study is to determine whether Saint John's wort, as an inducer of the CYP4503A4 isoform, diminishes the severity of Willis-Ekbom's disease symptoms by increasing the metabolism of thyroid hormone in treated patients.
  
  
  METHODS
  In an open-label pilot trial, we treated 21 Willis-Ekbom's disease patients with a concentrated extract of Saint John's wort at a daily dose of 300 mg over the course of three months.
  
  
  RESULTS
  Saint John's wort reduced the severity of Willis-Ekbom's disease symptoms in 17 of the 21 patients.
  
  
  CONCLUSIONS
  Results of this trial suggest that Saint John's wort may benefit some Willis-Ekbom's disease patients. However, as this trial was not placebo-controlled, the extent to which Saint John's wort is effective as a Willis-Ekbom's disease treatment will depend on future, blinded placebo-controlled studies.
authors.affiliation: Faculdade de Medicina de Jundiaí, Pediatria, Jundiaí/SP, Brazil. jcpereirajr@uol.com.br
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Pereira
authors.forename: Márcia
authors.initials: M
authors.lastname: Pradella-Hallinan
authors.forename: Rosana Cardoso
authors.initials: RC
authors.lastname: Alves
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D051544:Cytochrome P-450 CYP3A / Q000187:drug effects* / Q000378:metabolism; D065692:Cytochrome P-450 CYP3A Inhibitors; D005260:Female; D006801:Humans; D020902:Hypericum; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000627:therapeutic use*; D020033:Protein Isoforms / Q000187:drug effects / Q000378:metabolism; D012148:Restless Legs Syndrome / Q000188:drug therapy* / Q000201:enzymology; D012720:Severity of Illness Index; D013963:Thyroid Hormones / Q000378:metabolism; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D065692:Cytochrome P-450 CYP3A Inhibitors; D010936:Plant Extracts; D020033:Protein Isoforms; D013963:Thyroid Hormones; D051544:Cytochrome P-450 CYP3A