Fentanyl-induced rigidity during emergence from general anesthesia potentiated by venlafexine.
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.
Roy
Sébastien
S
Département d'anesthésiologie, Université de Montréal, Québec, Canada.
Fortier
Louis-Philippe
LP
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
D000701:Analgesics, Opioid; D018687:Antidepressive Agents, Second-Generation; D003511:Cyclohexanols; D009292:Narcotic Antagonists; D009270:Naloxone; D000069470:Venlafaxine Hydrochloride; D005283:Fentanyl