Alfentanil-Induced Rigidity in Newborn Infants

Abstract

The authors evaluated whether alfentanil could be given before treatment procedures in critically ill mechanically ventilated neonates without adverse effects. Alfentanil (mean dose 11.7 micrograms/kg, range 9-15) was given intravenously to 20 mechanically ventilated critically ill newborn infants (mean birth weight 2510 g, range 1490-3990) during the first 3 days of life before treatment procedures. Heart rate, arterial blood pressure, transcutaneous partial pressure of O2, respiratory rate, and general activity were observed continuously from 10 min before the administration of alfentanil until 1 h after it. Plasma alfentanil concentrations were measured in 15 subjects. The pharmacokinetics of alfentanil varied greatly among the subjects. The hemodynamic changes were not clinically significant, and the most important side effect was muscle rigidity. Nine infants had mild or moderate rigidity, which had little or no effect on ventilation. Four infants had severe rigidity and jerking comparable to convulsive activity, transiently impairing ventilation and oxygenation for approximately 5-10 min. Increased inspired oxygen and increased pressure by manual ventilation were needed to prevent hypoxemia. Electroencephalographic recordings for three infants during alfentanil administration showed no evidence of increased seizure activity. We conclude that alfentanil should not be used for newborn infants without simultaneous muscle relaxation because of the danger of rigidity.

Fentanyl-induced rigidity during emergence from general anesthesia potentiated by venlafexine

“…Cases associated with lower doses of opioid have also been documented in patients with particular risk factors: extremes of age (newborns, elderly) critical illness with neurological or metabolic diseases, and use of medications that modify dopamine levels. [11][12][13][14] For example, opioid-induced rigidity has been reported with a dose of fentanyl 150 µg in a patient taking haloperidol. 14 Our patient was taking venlafexine, an antidepressant that modifies norepinephrine and serotonin levels.…”

Neonatal chest wall rigidity following the use of remifentanil for cesarean delivery in a patient with autoimmune hepatitis and thrombocytopenia

“…Skeletal muscle rigidity may impede controlled or manual ventilation and has been reported in newborn infants after maternal exposure to fentanyl 17 and alfentanil, 18 but there have been no previous reports following the administration of remifentanil during cesarean section 1-5 or labor. [13][14][15] In our patient, doses higher than previously described in case reports were required and this, combined with possibly a higher free fraction of remifentanil (normally 70% protein bound, two-thirds to a 1 -acid glycoprotein 7 ) due to the liver dysfunction, may have resulted in higher free blood levels and more placental transfer.…”

Selection of Anesthesia Techniques for the Neonate

“…In neonates, a bolus of 9-15 μg/kg of alfentanil facilitates tracheal intubation and decreases the stress response to that procedure. However, alfentanil may induce a greater incidence of muscle rigidity than other opioids [ 200 ].…”