These drugs fall into two groups:
*Non-depolarizing blocking agents: These agents constitute the majority of the clinically relevant neuromuscular blockers.  They act by competitively blocking the binding of ACh to its receptors, and in some cases, they also directly block the ionotropic activity of the ACh receptors.
*Depolarizing blocking agents: These agents act by depolarizing the sarcolemma of the skeletal muscle fiber. This persistent depolarization makes the muscle fiber resistant to further stimulation by ACh.