title: Severe laryngeal dystonia in a patient receiving zuclopenthixol "Acuphase" and fluoxetine.
abstract: OBJECTIVE
  Prescribers are warned to be vigilant for potential cytochrome P450 mediated drug interactions; guidelines separately highlight risks of toxicity associated with zuclopenthixol acuphase. We previously examined potential cytochrome P450 interactions with zuclopenthixol and here describe dangerous side effects in a patient receiving zuclopenthixol acuphase and the selective serotonin reuptake inhibitor fluoxetine at high dose.
  
  
  METHODS
  We present the case of a patient established on fluoxetine 80 mg/day who subsequently received injected zuclopenthixol acuphase 100 mg.
  
  
  RESULTS
  Following zuclopenthixol acuphase administration, dangerous extra-pyramidal side effects were observed, including severe laryngeal dystonia necessitating emergency medical treatment.
  
  
  CONCLUSIONS
  Our observations of symptoms of zuclopenthixol toxicity are consistent with a cytochrome P450 2D6/3A4 interaction with fluoxetine. Previous evidence demonstrating this interaction included only patients taking fluoxetine up to 60 mg/day. This case extends the evidence base. In patients taking high dose fluoxetine, we advise marked reductions in the prescribed dose of zuclopenthixol acuphase.
authors.affiliation: School of Psychiatry & Clinical Neurosciences (M521), University of Western Australia, QEII Medical Centre, Perth, WA, Australia. sean.hood@uwa.edu.au
authors.forename: Sean
authors.initials: S
authors.lastname: Hood
authors.forename: Kenneth
authors.initials: K
authors.lastname: Orr
authors.forename: Lynette
authors.initials: L
authors.lastname: Bennett
authors.forename: Simon
authors.initials: S
authors.lastname: Davies
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D003006:Clopenthixol / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D003865:Major Depressive Disorder / Q000188:drug therapy*; D004347:Drug Interactions; D004359:Drug Therapy, Combination / Q000009:adverse effects*; D004421:Dystonia / Q000139:chemically induced*; D005260:Female; D005473:Fluoxetine / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D007821:Laryngeal Muscles / Q000187:drug effects; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D014150:Antipsychotic Agents; D003006:Clopenthixol; D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors; C060342:clopenthixol acetate ester