Understanding Anesthesiology - The Global Regional Anesthesia ...

REMIFENTANIL
Class
Synthetic opioid analgesic (ultra short-acting); adjunct
to anesthesia.
Mechanism of Action
Acts at the mu-and kappa opioid receptors.
Dose
On induction of general anesthesia: 0.3-1 ug/kg
For maintenance of general anesthesia: 0.1-1 $g/kg/
minute (by infusion)
For sedation: infusion 0.05 – 0.1 $g/kg/minute
Onset
After single bolus: 1-1.5 minutes
After initiation of infusion: 3-5 minutes
Duration
5-10 minutes; context sensitive half time 3 minutes
Elimination
Non-specific blood-tissue esterases (end-organ independent)
by concurrent use of sedatives, volatile anesthetics and
nitrous oxide.
CVS
Exaggerated bradycardia, hypotension (compared with
other opioids). The synthetic opioids are not direct myocardial
depressants but they do reduce sympathetic
drive, which may result in decreased cardiac output in
patients who are relying on sympathetic tone to support
their circulation, such as those in hypovolemic or
cardiogenic shock.
Respiratory
Profound respiratory depressant which often leads to
apnea.
GI
Nausea, vomiting.
Misc.
Can cause profound muscle rigidity. Not suitable for
spinal or epidural use due to glycine additive. Rapid
elimination requires initiation of post-operative analgesia
(usually morphine) prior to emergence.
Effects
CNS
Potent analgesic effects, sedation. “MAC sparing” allows
up to 75% reduction in dose of co-anesthetics. All
of the depressant effects of remifentanil are potentiated
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