Which neuromuscular blocking drug causes the greatest release of histamine when administered intravenously?

Which neuromuscular blocking drug causes the greatest release of histamine when administered intravenously?

• A. Succinylcholine
• B. d-Tubocurarine
• C. Doxacurium
• D. Atracurium

Answer: (B)

The key idea is that some neuromuscular blockers trigger histamine release from mast cells when given intravenously, causing vasodilation and potentially hypotension or bronchospasm. Among the options, the one known for the most pronounced histamine release is d-tubocurarine. This drug often produces marked hypotension and flushing due to histamine-mediated vasodilation, especially with IV administration or higher doses. The other agents can release histamine as well, but to a lesser extent: succinylcholine may cause mild to moderate histamine release, atracurium can cause histamine release but usually less severe than d-tubocurarine, and doxacurium has relatively minimal histamine release.

The key idea is that some neuromuscular blockers trigger histamine release from mast cells when given intravenously, causing vasodilation and potentially hypotension or bronchospasm. Among the options, the one known for the most pronounced histamine release is d-tubocurarine. This drug often produces marked hypotension and flushing due to histamine-mediated vasodilation, especially with IV administration or higher doses. The other agents can release histamine as well, but to a lesser extent: succinylcholine may cause mild to moderate histamine release, atracurium can cause histamine release but usually less severe than d-tubocurarine, and doxacurium has relatively minimal histamine release.