Cisatracurium is a stereoisomer of
atracurium that is four times more potent. Atracurium contains approximately
atracurium, cisatracurium undergoes degradation in plasma at
physiological pH and temperature by organ-independent Hofmann elimination. The
resulting metabolites (a mono-quaternary acrylate and laudanosine) have no
neuromuscular blocking effects. Because of cisatra-curium’s greater potency,
the amount of laudanosine produced for the same extent and duration of
neu-romuscular blockade is much less than with atra-curium. Nonspecific
esterases are not involved in the metabolism of cisatracurium. Metabolism and
elimination are independent of renal or liver failure. Minor variations in
pharmacokinetic patterns due to age result in no clinically important changes
in duration of action.
Cisatracurium produces good intubating
conditions following a dose of 0.1–0.15 mg/kg within 2 min and results in
muscle blockade of intermediate duration. The typical maintenance infusion rate
ranges from 1.0–2.0 mcg/kg/min. Thus, it is more potent than atracurium.
Cisatracurium should be stored under
refrig-eration (2–8°C) and should be used within 21 days
after removal from refrigeration and exposure to room temperature.
Unlike atracurium, cisatracurium does
not pro-duce a consistent, dose-dependent increase in plasma histamine levels
following administration. Cisatracurium does not alter heart rate or blood
pressure, nor does it produce autonomic effects, even at doses as high as eight
Cisatracurium shares with atracurium the
pro-duction of laudanosine, pH and temperature sensi-tivity, and chemical incompatibility.