Cisatracurium

Cisatracurium (usually as cisatracurium besilate, trade name Nimbex) is a neuromuscular-blocking drug. It is one of the ten isomers of atracurium. Its active metabolites contain less laudanosine which cause hypotension, central nervous system excitement, and seizures than that of atracurium. It is considered an intermediate-acting agent in terms of duration of action.

Structure
It is a benzyl-isoquinolinium agent in the quaternary ammonium compound family.

Metabolism
80% is metabolized to laudanosine via Hoffman Elimination (which is dependent on the pH and the temperature of the plasma) and 20% is metabolized hepatically or excreted renally. Since Hoffman elimination is organ-independent, the use of cisatracurium may pose less risk in patients with liver or renal disease than other neuromuscular blockers. 10-15% of the dose is excreted unchanged in the urine.