Which drug should be administered with caution to patients receiving echothiophate for glaucoma?

Which drug should be administered with caution to patients receiving echothiophate for glaucoma?

• A. Atropine
• B. Succinylcholine
• C. Ketamine
• D. Pancuronium

Answer: (B)

Echothiophate inhibits cholinesterase, so acetylcholine builds up at neuromuscular and parasympathetic sites. Succinylcholine is normally broken down by plasma cholinesterase (pseudocholinesterase) in a matter of minutes. If cholinesterase is inhibited by echothiophate, succinylcholine is not cleared quickly, leading to an unexpectedly prolonged depolarizing blockade and extended apnea. That’s why this drug should be used with caution (often avoided) in patients on echothiophate. Other drugs listed don’t hinge on rapid cholinesterase breakdown in the same way, so they don’t carry this specific risk.

Echothiophate inhibits cholinesterase, so acetylcholine builds up at neuromuscular and parasympathetic sites. Succinylcholine is normally broken down by plasma cholinesterase (pseudocholinesterase) in a matter of minutes. If cholinesterase is inhibited by echothiophate, succinylcholine is not cleared quickly, leading to an unexpectedly prolonged depolarizing blockade and extended apnea. That’s why this drug should be used with caution (often avoided) in patients on echothiophate. Other drugs listed don’t hinge on rapid cholinesterase breakdown in the same way, so they don’t carry this specific risk.