Cholinergic Agonists and Antagonists Flashcards
Acetycholine
Direct acting cholinomimetic
Bethanechol
direct acting cholinomimetic
Carbachol
direct acting cholinomimetic
Civemeline
direct acting cholinomimetic
Methacholine
direct acting cholinomimetic
Pliocarpine
direct acting cholinomimetic
Varenicline (Chantix)
direct acting cholinomimetic
Ambenonium
Cholinisterase inhibitor
Donepezil
Cholinesterase inhibitor
Echothiophate
Cholinesterase inhibitor
Edrophonium
Cholinesterase inhibitor
Galantamine
Cholinesterase inhibitor
Neostimine
Cholinesterase inhibitor
Physostigmine
Cholinesterase inhibitor
Pyridostigmine
Cholinesterase inhibitor
Rivastimine
Cholinesterase inhibitor
Tacrine
Cholinesterase inhibitor
Pralidoxime
Cholinesterase regenerator
Antimuscarinic drugs used for motion sickness
Scopolamine
Antimuscarinic drugs for GI disorders
Atropine
Dicyclomine
Glycopyrrolate
Hyoscyamine
Antimuscarinic drugs used in ophthamology
Atropine Cyclopentolate Homatopine Scopolamine Tropicamide
Antimuscarinic drugs used for respiratory disorders (asthma, COPD)
Ipratropium
Tiotropium
Antimuscarinic drugs used for urinary disorders
Darifenacin Fesoterodine Oxybutynin SOlifenacin Tolterodine Trospium
Antimuscarinic drugs used for cholinergic poisoning
Atropine (+ pralidoxime)
Antimuscarinic Drugs used for movement disorders
Benztropine Biperiden Orphenadrine Procyclidine Trihexyphenidyl
Ganglion blockers
Mecamylamine
Choline esters and alkaloids are what type of drugs
Direct acting cholinergic agonists
Choline esters MOA
Act as agonists on cholinergic receptors
Choline esters eg
acetylcholine
carbachol, bethanechol
Choline esters absorption, distribution and metabolism
permanently charged quartenary ammonium groups that result in poor absorption and distribution into the CNS
Hydrolyzed in the GI tract, less active when given by mouth
Hydrolysed by cholinesterase but at different rates –> varrying durations of action
Alkaloid MOA
acts as agonist on cholinergic receptors
Alkaloids eg
muscarine, nicotine, pliocarpine
Hydrolyzation speeds of choline esters by cholinesterase
most rapid: acetylcholine > methacholine> carbachol=bethanechol : least rapid
Alkaloids absorption, distribution and metabolism
uncharge tertiary amines (muscarine is an exception). well absorbed from most sites of administration
muscarine is a quartenary amine, is highly toxic when ingested, and can enter the brain (musrooms)
Cheifly excreted by the kidneys; acidification of the urine accelerates clearance.
M1, M3, M5
Gq, stimulatory, Ip3 DAG cascade
Nerves (M1)
Glands, smooth muscle, endothelium, (M3)
CNS (M5)
M2, M4
Gi, inhibitory, inhibition of cAMP production (activation of K+ch in M2)
M2 - heart, nerves, smooth muscle
M4 - CNS
Nicotinic receptors
Nm - skeletal NMJ
Nn - postganglionic cell body, dendrites, cns
Na, K depolarizing ion channel
Organ system effects of the direct acting cholinergic agonists Skeletal muscle (somatic effects)
only nACHRs ar on skeletal muscle, so only those agents that activate nACHR will produce any effect (muscle contraction)
Prolonged agonist occupancy of the nACHr abolishes the effector response: the postganglionic neuron stops firing and the skeletal muscle cell relaxes (similar to succiylcholine)
Eventually a state of depolarizing blockade is produced (flaccid paralysis)
Nicotine itself has a greater affinity for neuronal nACHRs than skeltal muscle nACHRs
Organ system effects of the direct acting cholinergic agonists
Eye
Contraction of iris sphincter and ciliary muscle –> increased aqueous humor outflow into canal of Schlemm
Organ system effects of the direct acting cholinergic agonists
Cardiovascular system
M2 mACHR
reduction in peripheral vascular resistance and changes in HR
