title: Hyperdopaminergic crises in familial dysautonomia: a randomized trial of carbidopa.
abstract: OBJECTIVE
  The purpose of this study was to determine whether carbidopa (Lodosyn), an inhibitor of dopa-decarboxylase that blocks the synthesis of dopamine outside the brain, is an effective antiemetic in patients with familial dysautonomia (FD) and hyperdopaminergic nausea/retching/vomiting attacks.
  
  
  METHODS
  We enrolled 12 patients with FD in an open-label titration and treatment study to assess the safety of carbidopa. We then conducted a randomized, double-blind, placebo-controlled, crossover study to evaluate its antiemetic efficacy.
  
  
  RESULTS
  Previous fundoplication surgery in each patient studied prevented vomiting, but all of the subjects experienced severe cyclical nausea and uncontrollable retching that was refractory to standard treatments. Carbidopa at an average daily dose of 480 mg (range 325-600 mg/day) was well tolerated. In the double-blind phase, patients experienced significantly less nausea and retching while on carbidopa than on placebo (p < 0.03 and p < 0.02, respectively). Twenty-four-hour urinary dopamine excretion was significantly lower while on carbidopa (147 ± 32 µg/gCr) than while on placebo (222 ± 41µg/gCr, p < 0.05).
  
  
  CONCLUSIONS
  Carbidopa is a safe and effective antiemetic in patients with FD, likely by reducing the formation of dopamine outside the brain.
  
  
  METHODS
  This study provides Class II evidence that carbidopa is effective in reducing nausea/retching/vomiting in patients with FD.
authors.affiliation: Dysautonomia Center, New York University School of Medicine, New York, NY, USA.
authors.forename: Lucy
authors.initials: L
authors.lastname: Norcliffe-Kaufmann
authors.forename: Jose
authors.initials: J
authors.lastname: Martinez
authors.forename: Felicia
authors.initials: F
authors.lastname: Axelrod
authors.forename: Horacio
authors.initials: H
authors.lastname: Kaufmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000932:Antiemetics / Q000627:therapeutic use; D002230:Carbidopa / Q000627:therapeutic use*; D002648:Child; D018592:Cross-Over Studies; D015259:Dopamine Agents / Q000627:therapeutic use*; D004311:Double-Blind Method; D004402:Dysautonomia, Familial / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D009325:Nausea / Q000188:drug therapy / Q000209:etiology; D014839:Vomiting / Q000188:drug therapy / Q000209:etiology; D055815:Young Adult
chemical_list: D000932:Antiemetics; D015259:Dopamine Agents; D002230:Carbidopa
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