I have to start off by saying I do have a small bias here and that this reading is largely a "Why I'd choose Rocuronium or Succinylcholine" piece. Rocuronium > Succinylcholine in my opinion — All day, every day. But with that being said, I have used Succinylcholine (and occasionally still do). I won’t “knock” anyone who chooses to use it… pending they have identified that no contraindications exist.
Pictured here is my “Quick Look” infographic looking at both Succinylcholine and Rocuronium; the benefits, considerations, and adverse effects:
I can’t just tell you that I think Rocuronium (Roc) is better than succinylcholine (Sux) without giving you my reasons why... RIGHT? Soooo, here we go with another “Pharmacology NOT Taught in Medic School” blog; this time, the Rocuronium Edition.
Be sure to check out “Pharmacology NOT Taught in Medic School — Succinylcholine Edition” for context.
When I am asked what my “go-to” RSI medications are, I give the typical basic Starbucks answer: Ketamine and Roc. And while I agree, it's "totes basic," I find that having a reason why makes it less cliche and more coming from an educated background. Do I choose them every time? Absolutely not. If I can find a better reason to choose another medication… I will.
The typical follow-up questions I get after I give that Ugg Boots response is usually:
What about if you fail the attempt, don’t you want them to start breathing again on their own?
It takes so much longer to work, aren’t you worried about desaturation during your intubation attempt?
You’re worried about contraindications… Why don’t you just perform a more thorough history?
I’m gonna answer these questions and give you the reason for my opinions, then I’ll give a deeper dive into Rocuronium.
"What about if you fail the attempt, don’t you want them to start breathing again on their own?"
I’m not sure why this is a question I get so often. My rebuttal is usually pretty simple… “If the patient was breathing well enough for that to be an option, then why are you taking that airway in the first place?” More often than not, I’d say that the patient falls under the typical indications for rapid sequence induction if we are choosing to paralyze in the pre-hospital or emergency environment: Airway protection or respiratory failure (ventilation failure or oxygenation failure). They likely still need airway protection or assistance with ventilation or oxygenation 10 minutes later, after Succinylcholine has worn off. Ask yourself, "Will the pre-existing condition remain following recovery from Succinylcholine?"
Take a look at the above picture. This is the oxyhemoglobin desaturation curve. If you look at the bottom right of the photo, you’ll notice the “recovery” window. Roughly 7 to 10 minutes in is when the Succinylcholine will wear off. And if you look at the blue lines indicating oxygen saturation, you’ll notice that the patient is INSANELY hypoxic at this point; maybe dead 🤷♀️. Doesn’t seem like something we can wait out.
“But Jared… i WiLl BaG tHeM tHrOuGh iT!”
I friggin’ hope so! But the goal still remains the same… You need an airway. The medication has worn off and now you may have to resort to administering Rocuronium anyway. Or, hopefully, maybe, you’ve resorted to an extra-glottic device prior to getting to this point.
If you weren’t successful at your first attempt, you’ve lost time. You may need to “bag them back up.” You’re losing more time… You're getting nervous... Haste makes waste... My plan is to obtain the airway as soon as possible. However, that doesn’t always happen. I want the effect of paralysis to maintain through any intervention I perform. If my intubation attempts were unsuccessful, I move to extra-glottic devices. If that is unsuccessful, I move to the knife. I want my patient paralyzed (and sedated) through the entirety of that potential chaos. If I must resort to bagging on my way to my destination, at least the patient is paralyzed (and hopefully sedated), not fighting the intervention.
Am I saying no situation exists where succinylcholine’s short duration isn’t appropriate? NO. But in the pre-hospital and emergency environment, I have found that a majority of my intubations were due to reasons that would still exist 10 minutes after I decided to push my paralytic. The exception has really only been patients whom I have intubated due to clinician safety concerns (inmates, combative, behavioral patients). Clinical judgment and critical thinking are imperative.
"It takes so much longer to work, aren’t you worried about desaturation during your intubation attempt?"
Sure. It absolutely crosses my mind. However, with the appropriate pre-oxygenation technique as discussed in the blog, “Weapon of Choice During Your RSI: Pre-oxygenation,” I find this putting some of those worries at ease.
I also find the following information useful:
Succinylcholine has an onset of approximately 45 seconds, whereas Rocuronium has an approximate onset of 60 to 90 seconds. That is substantial in some clinical scenarios, and not so much in others, in my opinion. But this is also, "source dependent" and "dose-dependent." In fact, Herbstritt 2012, identified that there was "no significant difference to time to intubate, intubating conditions, or intubating success rate when using 1 to 1.2 mg/kg Rocuronium versus 1 to 1.5 mg/kg of Succinylcholine during RSI in an ED setting." 
According to the package insert received with Rocuronium, "Neuromuscular block sufficient for intubation (80% block or greater) is attained in a median (range) time of 1 (0.4 to 6) minute(s) and most patients have intubation completed within 2 minutes. Maximum blockade is achieved in most patients in less than 3 minutes."
The Manual of Emergency Airway Management reports that Rocuronium "produces intubation-level paralysis consistently within 60 seconds, especially when an adequate dose of induction (sedative) agent is used, because the induction agent also causes substantial relaxation." 
In the Cochrane Library Database of Systematic Reviews: Rocuronium Versus Succinylcholine for Rapid Sequence Intubation, under the "Main Results," they report, "We found no statistical difference in intubation conditions (the ease with which physicians can quickly and safely pass the endotracheal tube) when Succinylcholine was compared to 1.2 mg/kg rocuronium; however, succinylcholine was clinically superior as it has a shorter duration of action." 
In an airway/review article by Dr. Scott Weingart and Dr. Richard Levitan titled, Preoxygenation and Prevention of Desaturation During Emergency Airway Management, it is reported that “Patients with high saturation levels on room air or after oxygen administration are at lower risk (for desaturation) and may maintain adequate oxygen saturations as long as 8 minutes.” 
Annals of Emergency Medicine. Airway/Review Article | Volume 59, Issue 3, P165-175.E1, March 01, 2012. https://www.annemergmed.com/article/S0196-0644(11)01667-2/fulltext
In that same article, it is reported that the time to desaturation after administration occurs faster with the use of Succinylcholine versus that of Rocuronium. Desaturation to 95% or lower was seen in 242 seconds (4 minutes) with Succinylcholine and desaturation to 95% or lower was seen in 378 seconds (6.3 minutes) with Rocuronium; both of which were following adequate preoxygenation measures. 
To add to the "desat" side of the drugs, Taha 2010, concluded, "when suxamethonium (Succinylcholine) is administered for rapid-sequence induction of anesthesia, a more rapid onset of oxygen desaturation is observed during the subsequent apnea as compared to rocuronium." 
Does this make you feel a tad better about choosing Rocuronium yet? My other rebuttal to this question is that if you are that worried about desaturation during the apneic phase, consider using appropriate, but also gentle, bag-mask ventilation technique leading up to laryngoscopy.
Check out this article on emDocs titled: Roc Rocks and Sux Sucks! Why Rocuronium is the Agent of Choice for RSI. 😏
Another quick read on the topic from Life in The Fast Lane: Does Roc Rock? Does Sux Suck?
"You’re worried about contraindications… Why don’t you just perform a more thorough history?"
Ok… You got me. I should have probably performed a more thorough history. I should have asked about a family history of malignant hyperthermia, performed a 12 lead ECG, and inquired about the patient's conditions, putting them at risk for hyperkalemia, including:
Pre-existing hyperkalemia (got that POC chem7 at the ready?)
Denervating injuries (eg, stroke, spinal cord injury), after 72 hours
Denervating diseases (eg, multiple sclerosis, amyotrophic lateral sclerosis)
Burns, after 72 hours
Crush injuries, after 72 hours
Severe infection with exotoxin production (eg, tetanus, botulism)
You know, because we’re not task saturated enough… Especially if we are working with minimal staffing or working a two clinician crew. I agree that we should perform the most thorough history possible, we really should try. But can you tell me that you have inquired about every one of these things before giving Succinylcholine? Think back to EVERY time you gave it… did you know ALL of this info? Was it even possible to identify them all?! I feel with Rocuronium, I don't have to worry about these issues. You know, sometimes it's all about feeling warm and fuzzy about your decisions, and Roc just does it for me.
Now let me give you this loooooong list of Rocuroniums absolute contraindications?
Let this be known. I am NOT anti-succinylcholine, I’m just pro Rocuronium for a small handful of reasons. Hopefully, this is information you all find useful and consider in the future. With some of my opinions out of the way, let us dive into Rocuronium.
Rapid sequence intubation with a NMBA is the current standard of care for emergency intubation. Multiple prospective studies and ED registry data confirm the high success rate of RSI with NMBAs when performed by experienced operators in both adult and pediatric emergency patients. [4-7]
Rocuronium is a non-depolarizing neuromuscular blocking agent (paralytic) widely used to produce muscle relaxation. It is one of many non-depolarizing neuromuscular blocking agents that is used, but has the distinct advantage over the others, for having a faster onset and being reversible. 
Mechanism of action:
The site of action for our paralytics is the neuromuscular junction (NMJ). The NMJ is a specialized synapse connection between the terminal end of a motor nerve and a muscle, consisting of three main parts: a presynaptic nerve terminal, a postsynaptic motor end-plate, and the space in between — the synaptic cleft. It is the site for transmission of action potential from nerve to muscle .
Normally, on arrival of an action potential at the nerve terminal, calcium channels open to cause influx. Increased calcium inside the nerve terminal causes a series of events leading to a release of the neurotransmitter acetylcholine from synaptic vesicles into the synaptic cleft. The released acetylcholine then binds to nicotinic acetylcholine receptors on the postsynaptic neuromuscular endplate. These receptors are acetylcholine-gated ion channels. The binding of acetylcholine to these receptors leads to another cascade of events that generates and transmits action potential to the cell membrane, ultimately resulting in muscle contraction .
Rocuronium is a non-depolarizing, competitive, NMBA that competes with and blocks the action of acetylcholine at the neuromuscular endplate’s postjunctional, cholinergic nicotinic (acetylcholine) receptors . When Rocuronium is introduced, the medication binds to the receptors on the neuromuscular endplate, inhibiting depolarization.
Like I stated, Rocuronium is a non-depolarizing NMBA. Unlike Succinylcholine, which is a depolarizing NMBA, Rocuronium won't cause defasciculations, and issues with hyperkalemia aren't present.
Rocuronium is an IV NMBA, serving a multipurpose role in emergency airway management and is the preferred non-depolarizing NMBA for emergency RSI.  Its clinical uses as we see it in the ER, pre-hospital environment, and critical care environment includes:
Neuromuscular blockade (paralysis) to facilitate endotracheal intubation
Continued paralysis of the mechanically ventilated patient
In appropriately premedicated and adequately anesthetized patients, rocuronium bromide will provide excellent or good intubating conditions in most patients . Dose:
0.6 to 1.2 mg/kg.
Higher doses can be used to provide intubating conditions similar to succinylcholine with a short onset time of approximately one minute . This dose is:
1.0 to 1.2 mg/kg
Onset time is faster, compared to other non-depolarizing NMBAs
Higher dosing creates a similar onset time to that of Succinylcholine 
May be used for postintubation continued paralysis, if desired or indicated
Of the non-depolarizing NMBAs, Rocuronium is the recommended choice for emergency RSI 
Onset time and duration are the shortest in its class (non-depolarizing NMBAs)
Reversal agent exists
Adverse Effects & Considerations:
Prolonged onset seen in low cardiac output (shock) states