Which muscle relaxant is eliminated most by renal excretion?

Which muscle relaxant is eliminated most by renal excretion?

• A. Pancuronium
• B. Vecuronium
• C. Rocuronium
• D. Atracurium

Answer: (A)

Elimination pathways of nondepolarizing neuromuscular blockers and how renal function influences their duration are being tested. Pancuronium is eliminated primarily by the kidneys, with a substantial amount excreted unchanged in the urine. Because its clearance relies heavily on renal excretion, impaired kidney function prolongs its action and increases the risk of prolonged weakness after surgery. In contrast, the other agents rely less on the kidneys. Vecuronium and rocuronium are mainly broken down by the liver, with some renal excretion of metabolites, so renal impairment has a smaller effect on their duration. Atracurium degrades mainly through Hofmann elimination and ester hydrolysis, which do not depend on renal function, making its renal excretion minimal. Thus, pancuronium is the muscle relaxant eliminated most by renal excretion.

Elimination pathways of nondepolarizing neuromuscular blockers and how renal function influences their duration are being tested. Pancuronium is eliminated primarily by the kidneys, with a substantial amount excreted unchanged in the urine. Because its clearance relies heavily on renal excretion, impaired kidney function prolongs its action and increases the risk of prolonged weakness after surgery.

In contrast, the other agents rely less on the kidneys. Vecuronium and rocuronium are mainly broken down by the liver, with some renal excretion of metabolites, so renal impairment has a smaller effect on their duration. Atracurium degrades mainly through Hofmann elimination and ester hydrolysis, which do not depend on renal function, making its renal excretion minimal.

Thus, pancuronium is the muscle relaxant eliminated most by renal excretion.