In this episode, I’ll compare succinylcholine vs rocuronium with magnesium pretreatment.
Succinylcholine and rocuronium are the two main neuromuscular blockers that are used in rapid sequence intubation.
Many clinicians have a strong preference for one or the other based on how they value the small differences between them.
Succinylcholine 1mg /kg IV has a faster onset of action than rocuronium 0.6 mg/kg IV, however this advantage disappears when a larger dose of 1.2 mg/kg rocuronium is used. Unfortunately, the larger dose comes with a longer duration of action, which may be clinically undesirable.
It is known that pretreatment with IV magnesium sulfate shortens the time of onset time of a 0.6 mg/kg dose of rocuronium. Investigators recently published in Anesthesia and Analgesia a randomized controlled trial that directly compared a 1 mg/kg IV succinylcholine dose with saline placebo to a 0.6 mg/kg IV rocuronium dose with magnesium 60 mg/kg IV pre-treatment.
The primary endpoint was the rate of excellent intubating conditions 60 seconds after administration of the neuromuscular blocking agent. Secondary endpoints included blood pressure and heart rate before induction, before and after intubation, and adverse events up to 24 hours postoperatively.
While 280 patients were enrolled, data on intubating conditions could only be analyzed for 259 patients. The rates of excellent intubating conditions were equivalent between groups at 45% with succinylcholine+saline and 46% with rocuronium+magnesium. Prespecified subgroups such as gender and the study center also had equivalent rates of excellent intubation conditions.
While mean heart rate was higher in the rocuronium+magnesium group, patients with at least one adverse event was higher in the succinylcholine+saline group at 28% compared to 11% for the rocuronium+magnesium group. Postoperative muscle pain was the most frequent adverse event in the succinylcholine+saline group. There was no difference between groups in blood pressure at any point.
The authors concluded:
IV pretreatment with MgSO4 followed by a standard intubating dose of rocuronium did not provide superior intubation conditions to succinylcholine but had fewer adverse effects.
Patients in the ED and ICU requiring RSI likely do not have time for an extra 15-minute infusion of magnesium to complete before an airway should be established. Therefore this study is likely to have greater relevance in OR settings than the ED or ICU. However, if the recovery time from rocuronium can be shortened by giving magnesium pretreatment in OR patients, that may eliminate or reduce the need for sugammadex to be used to reverse rocuronium’s effects.
Members of my Hospital Pharmacy Academy have access to my Airway Pharmacology Masterclass, where I cover paralytic and sedative choices for the 6 different types of airway scenarios, as well as how to anticipate and deal with complications related to intubation. The Hospital Pharmacy Academy is my online membership site that teaches pharmacists practical critical care and hospital pharmacy skills you can apply at the bedside so that you can become confident in your ability to save lives and improve patient outcomes. To get immediate access, go to pharmacyjoe.com/academy.
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