Cisatracurium (Nimbex)

Anesthesia Implications

Classification: Non-Depolarizing Neuromuscular Blocker, Bisquaternary Ammonium Benzylisoquinoline
Therapeutic Effects: Paralysis
Time to Onset: 4-5 minutes
Time to Peak: 4-5 minutes
Duration: 45-60 minutes after intubation. 35-45 minutes after redosing.

Primary Considerations

Surgeries Greater than 1 hour – The duration of action limits the use of this agent to surgeries expected to last an hour or more.

Rocuronium and Vecuronium alternative – This agent is especially good for patients that have compromised renal/hepatic failure. This is because it relies on Hofmann elimination and ester hyrolysis to be metabolized.

Defaciculation – Cisatracurium is NOT effective as a defaciculant.

Volatile Inhaled Anesthetics – Volatile anesthetics potentiate the neuromuscular blockade when using cisatracurium. Doses should be based on ideal body weight in the obese.

No histamin release – No histamine release and very little laudanosine as a metabolite, which makes this an ideal agent over atracurium.

Sugammadex – Neuromuscular blockade using Nimbex will have a faster onset and deeper level of blockade when administered after a sugammadex reversal.

Neonates – Nimbex is a very useful induction agent for neonates. There is no dependence on liver function, which is reduced in the neonate.

IV push dose

Intubating: 0.15 mg/kg
Redosing/Maintenance: 0.1 mg/kg

Reversal

Neostigmine 40 mcg/kg. MAX dose in adults is 5mg. Neostigmine is typically administered (where not contraindicated) with glycopyrrolate. The dose of glycopyrrolate is 0.2 mg for every 1 mg of Neostigmine. Median recovery times from a TOF ratio of 0.5 back to 1.0 is 4.3 minutes.

Method of Action

The nicotinic cholinergic receptor at the skeletal muscle motor end-plate normally receives acetylcholine, which leads to muscle contraction. Cisatracurium is a competitive antagonist to acetylcholine. This means it essentially “blocks” acetylcholine by binding at the same receptor, preventing skeletal muscle contraction.

Metabolism

Hofmann Elimination and Ester Hydrolysis

Elimination

Hofmann Elimination and Ester Hydrolysis

Additional Notes
As pH or temperature increases, so does the metabolism (Hofmann elimination)