Page 29 - CASA Bulletin of Anesthesiologisy 2022 9(6)-1 (3)

Vol. 9, No 6, 2022

Gabapentinoids given on the day of surgery were also associated with increased risk of
postoperative complications (ie. respiratory failure, pneumonia, reintubation) due to respiratory
depression independent of opioid use . In 2019, the FDA issued a drug safety alert on serious
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breathing problems with gabapentin and pregabalin in patients with respiratory problems or those
taking CNS depressants. Day of surgery gabapentinoids is also associated with increased risk of
ICU admissions without decreasing opioid requirements or hospital length of stay . The French
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Society of Anesthesia and Intensive Care Medicine no lonbger recommends gabapentinoids
being used as part of the routine perioperative regimen. With the risks of gabapentinoid use
outweighing the benefits, current evidence forces us to re-evaluate the routine use of
perioperative gabapentinoid in adults.

Sufentanil
Sufentanil is a potent, central mu opioid agonist that produces analgesia. Intravenous
administration is not an effective postoperative analgesic because of its rapid decline in plasma
concentration following cessation. However, sublingual administration has a longer duration of
action and high bioavailability. Compared to oral sufentanil which has a bioavailability of 9%,
sublingual sufentanil has a bioavailability of 60%. Sufentanil is highly lipophilic and crosses the
blood brain barrier easily and has a potency that is 400 times stronger than that of morphine.
Sufentanil is 12 times more potent than fentanyl with similar onset of time of 6.2 min (The onset
of time for fentanyl is 6.6 min). The patient-controlled dispensary system for sublingual
sufentanil is similar to PCA (patient controlled analgesia) pumps and dispenses 15 ug tablets
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every 20 minutes. It can be continued up to 72 hours postoperatively .
Although IV PCAs provide excellent analgesia and high patient satisfaction, it has been
associated with issues such as infection, analgesic gaps (due to tubing obstructions) and
respiratory depression. Sufentanil sublingual tablet system (SSTS) has been able to address such
issues: Unlike morphine whose active metabolite (Morphine-6-Glucuronide, M6G) reaches its
peak concentration hours following its dose event, sufentanil lacks active metabolites, decreasing
the risk of delayed respiratory depression. Sublingual administration eliminates the risks
associated with administering medications intravenously (ie. obstruction, catheter infiltration).
Studies have shown that SSTS provides higher patient & nurse satisfaction due to its faster onset
of analgesia and ease of use of the device compared to morphine PCAs . However, according to
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Kim et al., there was no difference in postoperative pain following lumbar fusion surgeries
between IV fentanyl and sufentanil PCA. IV sufentanil PCA did have a lower postoperative
nausea and vomiting rate compared to fentanyl .
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Methadone

Methadone is another option that can be used for postoperative pain due to its prolonged
duration of action. The elimination half-life of methadone is approximately 22 hours. However,
the metabolism may vary greatly between individuals due to variation in CYP 3A4, 2B6 and 2D6
expression. It is more commonly used for chronic pain, but the potential benefits of methadone
in reducing the need for PCAs postoperatively offers much potential. Methadone for
postoperative analgesia can be given orally 0.2-0.3 mg/kg prior to induction or as a single
intravenous bolus 0.14-0.2 mg/kg intraoperatively. 0.2 mg/kg methadone intraoperatively
decreases pain scores and postoperative pain requirements by 50% up to 72 hours
postoperatively. However, intraoperative methadone has been associated with side effects such

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