Article Notes
- Atracurium – 1 in 22,500
- Rocuronium – 1 in 2,500
- Suxamethonium – 1 in 2,000
Australia and New Zealand both experience an unusually high incidence of perioperative anaphylaxis, particularly to neuromuscular blocking drugs. The opioid-based anti-tussive pholcodine has been implicated in increasing population hypersensitivity to muscle relaxants.
Although historically difficult to identify accurate denominator numbers for incidence calculations, more recent data shows that the anaphylaxis risk for rocuronium is particularly high in Australia & New Zealand and may in fact be roughly comparable to the local risk of suxamethonium anaphylaxis, at 1 in 2,000-3,000 exposures.
Rocuronium also has a higher risk of anaphylaxis than it’s aminosteroid-sibling vecuronium, and up to a ten-times greater risk than the benzylisoquinolinium atracurium (~1 in 22,500, depending on population). Cisatracurium demonstrates the lowest incidence of anaphylaxis (~1 in 50,000).
Additionally, as sugammadex appears as a new anaphylaxis cause the potential for a rocuronium-sugammadex combination having an even higher risk of anaphylaxis than suxamethonium needs to be considered.
Daniel Jolley
This retrospective, observational cohort study over 6 years from Auckland, New Zealand identified a 10 fold higher incidence of anaphylaxis for rocuronium than for atracurium.
Also of note, the rate of anaphylaxis to rocuronium was similar to that for suxamethonium.
Anaphylaxis incidence for the three muscle relaxants were approximately:
Daniel Jolley
Why is this important?
Despite growth of regional and non-opioid analgesic options, opioids remain the mainstain of peri-operative management of moderate to severe pain. IV patient-controlled analgesia (PCA) is a safe, common and reliable delivery mechanism.
What did they do?
Dinges et al. performed a network meta-analysis of 63 studies covering 16 different PCA opioids, comparing side-effects at equianalgesic doses. Morphine was used as the baseline comparator.
And they found?
Although there were some small difference in the incidence of nausea & vomiting (fentanyl having lowest N&V risk, buprenorphine highest) and pruritus (nalbuphine, butorphanol, methadone, and pethidine/meperidine resulting in least pruritis), there were significant differences for sedation and satisfaction.
Pethidine/meperidine, fentanyl & oxymorphone showed the lowest sedation scores, although respiratory depression events were too infrequent to show differences. Oxycodone, alfentanil, remifentanil, fentanyl & pethidine/meperidine resulted in the highest patient satisfaction and tramadol was the least satisfying.
Take-home message
Although some PCA-opioids perform better than others in small ways, overall side-effect profiled are very similar and comparably safe. Oxycodone, alfentanil and remifentanil however result in significantly higher patient satisfaction.
The big picture...
Rather than focusing on the small differences among opioids, there is almost certainly more to be gained by a disciplined, multi-modal analgesic focus that reduces opioid use and thus side-effects.
Daniel Jolley