These are the drugs which stimulate the
parasympathetic system and mimic the
action of acetylcholine. The acetylcholine
receptor stimulants and cholinesterase
inhibitors together comprise a large group
of drugs that initiate the action of
acetylcholine. They belong to the various
groups (Table 3.4.1).Table 3.4.1: Classification of cholinergic agents.
I. Choline esters
Acetylcholine
Methacholine (Acetyl-β-methylcholine) 5-10 mg SC
Carbachol (Carbamocholine) 1-4 mg oral, 0.25-0.5 mg SC and 0.75-3.0% topical
(eye).
Bethanechol (Carbamoyl-β-methylcholine;
UROCONTIN) 10-40 mg oral, 2.5-5.0 mg SC
II. Naturally occurring alkaloids
Pilocarpine (PILOCAR) 1, 2, 4% topical (eye)
III. Anticholinesterases (Cholinesterase inhibitors)
i. Reversible
Physostigmine (BIO-MIOTIC) 0.5-1 mg oral/IM, 0.1-1.0% topical (eye)
Neostigmine (PROSTIGMIN) 15-30 mg TDS oral, 0.5-5.0 mg IM/SC, 3-5% topical
(eye)
Pyridostigmine (MYESTIN) 60-180 mg oral, 1-5 mg IM/SC
Edrophonium 1-10 mg IV
Distigmine 5 mg oral, 0.5 mg IM
Rivastigmine, Donepezil, Tacrine etc. (used in Alzheimer’s disease).
ii. Irreversible
Diisopropyl fluorophosphate (DFP; DYFLOS) 0.025% topical (eye)
Hexaethyl tetraphosphate (HETP)
Certain insecticides such as parathion and malathion.Chapter
1.4
Chapter
3.4
Parasympathomimetics
(Cholinergic Agents)(Cholinergic Agents)(Cholinergic Agents)(Cholinergic Agents)(Cholinergic Agents)