Time of onset from most rapid to least rapid for reversal agents is which of the following sequences?

Time of onset from most rapid to least rapid for reversal agents is which of the following sequences?

• A. Edrophonium, pyridostigmine, neostigmine
• B. Edrophonium, neostigmine, pyridostigmine
• C. Neostigmine, edrophonium, pyridostigmine
• D. Neostigmine, pyridostigmine, edrophonium

Answer: (B)

The time to reversal at the neuromuscular junction depends on how quickly each acetylcholinesterase inhibitor acts. Edrophonium is a very fast-acting, short-acting inhibitor, so its onset is typically about 1–2 minutes after IV administration. Neostigmine has a slower onset, usually around 7–11 minutes, with a moderate duration of action. Pyridostigmine takes the longest to onset, roughly 10–20 minutes, though its duration is longer. So, from most rapid to least rapid onset, the sequence is edrophonium, then neostigmine, then pyridostigmine. The other sequences place a slower-onset agent before a faster one, which isn’t consistent with how quickly these drugs work. In clinical use, these agents are given with an anticholinergic to blunt muscarinic side effects.

The time to reversal at the neuromuscular junction depends on how quickly each acetylcholinesterase inhibitor acts. Edrophonium is a very fast-acting, short-acting inhibitor, so its onset is typically about 1–2 minutes after IV administration. Neostigmine has a slower onset, usually around 7–11 minutes, with a moderate duration of action. Pyridostigmine takes the longest to onset, roughly 10–20 minutes, though its duration is longer.

So, from most rapid to least rapid onset, the sequence is edrophonium, then neostigmine, then pyridostigmine. The other sequences place a slower-onset agent before a faster one, which isn’t consistent with how quickly these drugs work. In clinical use, these agents are given with an anticholinergic to blunt muscarinic side effects.