Updated July 2026 · 9 min read
Part of the ICU Emergencies Hub — browse every related guide in one place.
In rapid sequence intubation the paralytic buys the team a still, relaxed airway for the few seconds that matter most. Two drugs dominate that slot: succinylcholine, the fast, short-acting classic, and rocuronium, the safer-in-many-ICU-patients alternative. Knowing why the team picks one over the other — and what each commits you to afterward — is core ICU knowledge.
Succinylcholine is a depolarizing blocker: it mimics acetylcholine, briefly activating the muscle (you see fasciculations) and then holding the junction open so the muscle can't re-fire. It is broken down by plasma pseudocholinesterase, which is why its effect is so short. Rocuronium is a non-depolarizing blocker: it competitively blocks the acetylcholine receptor without activating it — no fasciculations — and its effect ends as the drug redistributes and is cleared, mostly hepatically.
Both give intubating conditions in roughly 45–60 seconds when rocuronium is dosed at the higher RSI dose. The decisive difference is the back end. Succinylcholine's paralysis fades in about 5–10 minutes, so a patient can begin breathing again relatively quickly if the airway can't be secured. Rocuronium at RSI dosing keeps the patient paralyzed for 45–60+ minutes. That long tail is the single most important thing to understand: with rocuronium and no reversal agent immediately available, a failed intubation means an apneic, fully paralyzed patient for a long time — which is exactly why sugammadex being on hand changes the calculus.
Other cautions: succinylcholine transiently raises potassium even in normal patients, can cause bradycardia (especially in children or with repeat dosing), raises intraocular and intracranial pressure modestly, and the fasciculations produce post-procedure myalgias. This long hazard list is precisely why many ICUs now default to rocuronium for the crashing, often hyperkalemia-prone critically ill patient.
Rocuronium sidesteps the hyperkalemia and malignant-hyperthermia problems entirely, which is its main appeal in the ICU. Its costs are the long duration already discussed and the fact that it provides no sedation or analgesia — a point that applies to succinylcholine too. A paralyzed patient who is under-sedated is fully aware and unable to move or signal. Ensuring adequate sedation and analgesia alongside any paralytic is a nursing safety imperative, not an afterthought.
Succinylcholine needs no reversal — you wait it out. Rocuronium (and vecuronium) can be reversed with sugammadex, which encapsulates the drug and can reverse even a deep block within minutes; neostigmine reverses only a shallow block and works more slowly. The ready availability of sugammadex is a major reason rocuronium has become a comfortable RSI choice: the "committed airway" concern is mitigated when a rescue reversal is minutes away.
| Feature | Succinylcholine | Rocuronium |
|---|---|---|
| Class | Depolarizing | Non-depolarizing |
| Onset | ~45–60 sec | ~45–60 sec (RSI dose) |
| Duration | ~5–10 min | ~45–60+ min |
| Fasciculations | Yes | No |
| Key contraindications | Hyperkalemia/risk, MH, burns/crush/denervation, pseudocholinesterase deficiency | Few; caution in hepatic impairment (longer effect) |
| Reversal | None needed (self-limited) | Sugammadex (fast) or neostigmine (shallow only) |
| Sedation provided | None | None |
Related: Etomidate vs ketamine for RSI · Sugammadex vs neostigmine · Hyperkalemia emergency treatment · Malignant hyperthermia
Educational content for licensed clinicians. Always follow your facility's pharmacy dosing protocol and provider orders. Not medical advice.
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