An elderly woman with moderate Alzheimer's disease and comorbid sick sinus syndrome requiring a pacemaker needs a cholinesterase inhibitor. Her cardiologist warns against agents that can worsen conduction. Among the cholinesterase inhibitors, which agent uniquely inhibits both acetylcholinesterase and butyrylcholinesterase and is available as a transdermal patch?
- A Donepezil
- B Galantamine
- C Rivastigmine ✓
- D Tacrine
Correct answer: C. Rivastigmine
Explanation
Rivastigmine inhibits both acetylcholinesterase and butyrylcholinesterase and is available as a once-daily transdermal patch, which reduces gastrointestinal side effects compared with oral dosing. All cholinesterase inhibitors can cause bradycardia and syncope via vagotonic effects, so cardiac monitoring is needed regardless of agent. Tacrine was the first drug approved for Alzheimer's disease but was withdrawn because of hepatotoxicity, which defeats option D.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.