Comparison of two muscle relaxants, rocuronium and succinylcholine, to facilitate rapid sequence induction intubation

Review question

Which drug (rocuronium or succinylcholine) is better at providing excellent conditions to quickly insert breathing tubes into participants of all ages for elective and emergency situations?


In emergency situations some people need a general anaesthetic with an endotracheal tube (a tube to help them breathe). It is important to have fast-acting medications to allow physicians to complete this procedure quickly and safely. Currently, the medication used most frequently to relax muscles is succinylcholine. Succinylcholine is fast-acting and lasts for only a few minutes, which is very desirable in this setting. However, some people cannot use this medication as it can cause serious salt imbalances or reactions, so an equally effective medication without these side effects would be advantageous. One possible alternative medication is rocuronium, a muscle relaxant with fewer side effects but longer duration of action. This review compares the quality of intubation conditions (the ease with which physicians can quickly and safely pass the endotracheal tube) between rocuronium and succinylcholine in all ages and varying clinical situations.

Study characteristics

We included in the review controlled trials from 1966 to February 2015 involving participants of all ages needing rapid intubation using rocuronium and succinylcholine . The minimum dose of rocuronium given was 0.6mg/kg and succinylcholine was 1mg/kg. We have combined the results of 50 trials, with a total of 4151 participants, which compared the effectiveness of succinylcholine versus rocuronium on intubation conditions. No major side effects from use of the drugs were reported.

Key results

We have found that rocuronium is slightly less effective than succinylcholine for creating excellent and acceptable intubation conditions. Rocuronium should therefore only be used as an alternative to succinylcholine when it is known that succinylcholine should not be used and a more prolonged intubation is expected.

Quality of evidence

The level of evidence is of moderate GRADE due to imperfect study designs and varying techniques used across trials .

Authors' conclusions: 

Succinylcholine created superior intubation conditions to rocuronium in achieving excellent and clinically acceptable intubating conditions.

Read the full abstract...

Patients often require a rapid sequence induction (RSI) endotracheal intubation technique during emergencies or electively to protect against aspiration, increased intracranial pressure, or to facilitate intubation. Traditionally succinylcholine has been the most commonly used muscle relaxant for this purpose because of its fast onset and short duration; unfortunately, it can have serious side effects. Rocuronium has been suggested as an alternative to succinylcholine for intubation. This is an update of our Cochrane review published first in 2003 and then updated in 2008 and now in 2015.


To determine whether rocuronium creates intubating conditions comparable to those of succinylcholine during RSI intubation.

Search strategy: 

In our initial review we searched all databases until March 2000, followed by an update to June 2007. This latest update included searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 2), MEDLINE (1966 to February Week 2 2015), and EMBASE (1988 to February 14 2015 ) for randomized controlled trials (RCTs) or controlled clinical trials (CCTs) relating to the use of rocuronium and succinylcholine. We included foreign language journals and handsearched the references of identified studies for additional citations.

Selection criteria: 

We included any RCT or CCT that reported intubating conditions in comparing the use of rocuronium and succinylcholine for RSI or modified RSI in any age group or clinical setting. The dose of rocuronium was at least 0.6 mg/kg and succinylcholine was at least 1 mg/kg.

Data collection and analysis: 

Two authors (EN and DT) independently extracted data and assessed methodological quality for the 'Risk of bias' tables. We combined the outcomes in Review Manager 5 using a risk ratio (RR) with a random-effects model.

Main results: 

The previous update (2008) had identified 53 potential studies and included 37 combined for meta-analysis. In this latest update we identified a further 13 studies and included 11, summarizing the results of 50 trials including 4151 participants. Overall, succinylcholine was superior to rocuronium for achieving excellent intubating conditions: RR 0.86 (95% confidence interval (CI) 0.81 to 0.92; n = 4151) and clinically acceptable intubation conditions (RR 0.97, 95% CI 0.95 to 0.99; n = 3992, 48 trials). A high incidence of detection bias amongst the trials coupled with significant heterogeneity provides moderate-quality evidence for these conclusions, which are unchanged from the previous update. Succinylcholine was more likely to produce excellent intubating conditions when using thiopental as the induction agent: RR 0.81 (95% CI: 0.73 to 0.88; n = 2302, 28 trials). In the previous update, we had concluded that propofol was the superior induction agent with succinylcholine. There were no reported incidences of severe adverse outcomes. We found no statistical difference in intubation conditions when succinylcholine was compared to 1.2 mg/kg rocuronium; however, succinylcholine was clinically superior as it has a shorter duration of action.