Which drug could effectively reverse the effects of a nondepolarizing neuromuscular blocker used during surgery?

Neostigmine is a reversible acetylcholinesterase inhibitor, which means that its primary function is to inhibit the enzyme that breaks down acetylcholine in the neuromuscular junction. When nondepolarizing neuromuscular blockers are used during surgery, they compete with acetylcholine for binding to nicotinic receptors at the motor end plate, leading to muscle paralysis. By administering neostigmine post-surgery, the increased levels of acetylcholine can outcompete the neuromuscular blocker, effectively reversing the paralysis by restoring the ability of the muscles to contract.

In contrast, drugs like pilocarpine and bethanechol primarily act on muscarinic receptors and are not effective in reversing the effects of neuromuscular blockers as they do not directly influence nicotinic receptors where the neuromuscular blockers exert their action. Atropine is an anticholinergic that blocks the effects of acetylcholine at muscarinic receptors, which would not aid in reversing the effects of neuromuscular blockade and could, in fact, worsen muscle weakness by further reducing acetylcholine's action.

Thus, neostigmine is the correct choice because it directly increases acetylcholine levels at the