Anticholinergics

Question 1

Atropine

Answer 1

• administered prior to bronchoscopy to decrease respiratory mucus secretions and promote bronchodilation.
• Anticholinergic drugs competitively inhibit the muscarinic acetylcholine receptor both centrally (leading to delirium, coma, and respiratory failure) and peripherally
• elderly are at particularly high risk of developing anticholinergic toxicity, likely due to decreased renal and hepatic clearance.

Question 2

Cholinesterase inhibitors

Answer 2

• inhibiting the degradation of acetylcholine, thereby increasing the concentration of acetylcholine at the synaptic cleft.
• Central nervous system (CNS) penetration and reversal of central symptoms are dependent on chemical structure:

1. Tertiary amines (eg, physostigmine, galantamine, donepezil, rivastigmine) are lipophilic (nonpolar) and can easily cross the blood-brain barrier to reverse both central and peripheral symptoms.
2. Quaternary amines (eg, neostigmine, edrophonium, pyridostigmine) = NEP are hydrophilic (polarized) and do not readily cross the blood-brain barrier. These drugs reverse peripheral symptoms only