title: Fentanyl-induced rigidity during emergence from general anesthesia potentiated by venlafexine.
abstract: OBJECTIVE
  To present and discuss a case of opioid-induced rigidity with low-dose fentanyl during recovery from anesthesia.
  
  
  METHODS
  A 41-yr-old woman underwent laparotomy for total abdominal hysterectomy and bilateral salpingo- oophorectomy under general anesthesia. She received a total of 500 micro g of fentanyl by iv intermittent boluses during the three-hour anesthetic. During emergence from anesthesia, while intubated, the patient presented with rigidity. No changes in ventilatory parameters were measured during the episode. The only notable predisposing factor was treatment with venlafexine, an antidepressant that modifies serotonin and norepinephrine levels. She was successfully treated with iv naloxone 20 micro g. The rest of the postoperative period was uneventful.
  
  
  CONCLUSIONS
  We observed an atypical case of opioid-induced rigidity in contrast to the classical syndrome, which presents at induction with high-dose opioids. This syndrome has many clinical presentations with neurologic and ventilatory signs of varying intensity. Early recognition of the syndrome and adequate treatment is crucial. If treated adequately, opioid-induced rigidity is self-limited with few complications.
authors.affiliation: Département d'anesthésiologie, Université de Montréal, Québec, Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Roy
authors.forename: Louis-Philippe
authors.initials: LP
authors.lastname: Fortier
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000009:adverse effects*; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General; D018687:Antidepressive Agents, Second-Generation / Q000009:adverse effects*; D003511:Cyclohexanols / Q000009:adverse effects*; D004357:Drug Synergism; D005260:Female; D005283:Fentanyl / Q000009:adverse effects*; D006801:Humans; D009127:Muscle Rigidity / Q000188:drug therapy / Q000209:etiology*; D009270:Naloxone / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000627:therapeutic use; D000069470:Venlafaxine Hydrochloride
chemical_list: D000701:Analgesics, Opioid; D018687:Antidepressive Agents, Second-Generation; D003511:Cyclohexanols; D009292:Narcotic Antagonists; D009270:Naloxone; D000069470:Venlafaxine Hydrochloride; D005283:Fentanyl