title: The two sides of opioids in cyclical vomiting syndrome.
abstract: BACKGROUND
  Cyclical vomiting syndrome is increasingly recognized in adults, with recent reports suggesting 'coalescing attacks' in one third of the patients. We hypothesized that the common need for opioid treatment may contribute to coalescing attacks through development of opioid dependence and withdrawal, triggering cyclical vomiting syndrome.
  
  
  OBJECTIVE
  This study was to review iatrogenic opioid dependence as the potential cause for triggering cyclical vomiting syndrome.
  
  
  METHODS
  A retrospective review was performed to identify patients treated for cyclical vomiting syndrome by a single physician between Jan and December of 2010. Demographic data, clinical presentation, treatment, cumulative opioid prescription during hospitalizations and emergency room visits and days of inpatient stay were abstracted from the chart.
  
  
  RESULTS
  Forty-one patients (mean age 37.5.6 ± 2.6 years; 66% female) were seen within this timeframe. In eleven patients (27%) with ongoing opioid use, the initial cyclical illness had progressed and eventually coalesced. A cohort of 23 patients was followed for at least 6 months (12.3 ± 1.7 months). The best single predictor of repeat hospitalizations was the cumulative opioid dosage.
  
  
  CONCLUSIONS
  Continued use of opioid therapy is a poor prognostic marker of cyclical vomiting syndrome and may contribute to disease coalescence, with dependence and withdrawal triggering recurrent episodes.
authors.affiliation: Departments of Medicine and Gastroenterology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA ; Department of Gastroenterology, Kansas University School of Medicine, Kansas City, Missouri, USA.
authors.forename: Shreyas
authors.initials: S
authors.lastname: Saligram
authors.affiliation: Departments of Medicine and Gastroenterology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bielefeldt
keywords: Coalescing attacks; Cyclical vomiting syndrome; Opioids
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