Page 31 - CASA Bulletin of Anesthesiologisy 2022 9(6)-1 (3)

Vol. 9, No 6, 2022

Liposomal Bupivacaine

Local anesthetics have been frequently injected into surgical sites to provide postoperative
analgesia. In order to prolong the duration of action, long acting local anesthetics (ie
bupivacaine) has been encased in liposomes so that they would be released over a longer period
of time. However, recent meta-analysis including 13 RCTs suggests that there are few, if any,
benefits in switching from intraoperative infiltration with unencapsulated bupivacaine to
liposomal bupivacaine .
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Opioids

Opioids is one of the most common analgesics used in the perioperative setting but is also
associated with unwanted opioid related adverse events (ORAES) which complicates dosing and
management. Opioids bind non-selectively to mu receptors to activate both the G protein
signaling pathway and the beta-arrestin pathway that is responsible for desired analgesic effects
and ORAES (ie respiratory depression, constipation) respectively. Recent studies have led to the
w ‘ ’
signaling pathway without activating the beta arrestin pathway that cause ORAES.

Biased agonism (also known as functional selectivity) refers to agonists that preferentially
activate one signaling pathway over another. Oliceridine is an example of a mu-GPS modulator
that is actively being developed for pain management. Oliceridine is a newly approved FDA
ligand bias opioid that has the ability to differentially activate the G protein signlaing pathway
and provide pain relief with a decreased side effect profile (ie respiratory depression, nausea,
vomiting) compared to morphine broadening the therapeutic window while decreasing ORAEs .
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The onset of time of Oliceridine is 1-2 minutes with a duration of action of 1-3 hours. It is up to
five times more potent compared to morphine. A 1-2 mg loading dose can be given and
supplemented with 1-3 mg every 1-3 hours as needed. The recommended PCA dosing regimen
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consists of a loading dose of 1.5 mg with 0.35 or 0.5 mg demand dose with a 6-minute lockout .

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Figure 1. Mechanism of action of conventional opioids versus mu-GPS modulators

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