Atropine

• Naturally occuring muscarinic antagonist
• Competitive antagonist at all muscarinic receptors
• Tertiary amine widely distributes and goes into CNS
• Excreted unchanged in urine, except for in rabbits that rapidly metabolize via atropine esterase

Physostigmine

• Indirect acting reversible ACE Inhibitor
• much slower enzyme kinetics for the rate limiting step of AChE (hydrolysis of covalent bond between acetylate and AChE)
• Tertiary amine, and is absorbed well and can be used topically in eye. Distributed to CNS and thus can be toxic

Bethanechol

• Synthetic direct acting cholinomimetic that only activates muscarinic receptors

d-Tubocurarine

• Non-depolarizing NM Blocker
• Can be reversed by AChE inhibitor
• May result in a bit of histamine release and weak block of autonomic ganglia
• Musts be adminstered IV because quaternary amine

Succinylcholine

• Depolarizing NM Blocker
• 2 ACh in tandem
• AChE inhibitor will make it worse rather than reverse
• Must be given IV due to quaternary amine
• Stim autonomic ganglia and has inotropic/chronotropic effects