Adrenergic & Cholinergic Drugs Flashcards
Acetylcholine
Direct nicotinic and muscarinic agonist, choline ester, quaternary ammonium, rapidly hydrolyzed by Ach-ase.
Used to obtain rapid miosis in cataract surgery.
Methancholine
Direct muscarinic agonist. Choline ester, quaternary ammonium. More resistant to Ach-ase.
Used to diagnose bronchial airway hyperreactivity.
Bethanechol
Direct muscarinic agonist. Choline ester, quaternary ammonium. More resistant to Ach-ase.
Used to treat atony of post-op urinary retention and atony of the bladder.
Pilocarpine.
Direct partial muscarinic agonist. natural alkaloid. Tertiary amine. Resistant to ach-ase.
Used to treat glaucoma and dry mouth after radiotherapy.
Nicotine
Direct nicotinic receptor agonist. Natural alkaloid. Tertiary amine.
At low dose it will stimulate both sympa and parasympa ganglions by depolarization. At high doses it will cause ganglionic and neuromuscular blockade.
Edrophonium
Choline-esterase inhibitor. (indirect-acting cholinergic agent). Short-lived reversible inhibition. Quaternary ammonium, does not enter CNS.
Used to diagnose Myasthenia Gravis. Used to reverse neuromuscular block produced by non-depolarizing muscular blockers.
Phyostigmine
Choline esterase inhibitor (indirect cholinergic agent). Tertiary amine. Can enter and act in CNS. Carbamate- forms covalent bond with ach-ase.
Used to treat overdoses of anticholinergic drugs.
Neostigmine
Choline esterase inhibitor (indirect cholinergic agent). Quaternary ammonium, can’t enter CNS. Carbamate- forms covalent bond with ach-ase.
Used to treat urinary retention, myasthenia gravis, and reverse effects of non-depolarizing neuromusc blockers afer surgery.
Pyridostigmine
Choline esterase inhibitor (indirect cholinergic agent). Quaternary ammonium, can’t enter CNS. Carbamate- forms covalent bond with ach-ase.
Used to treat myasthenia gravis.
Organophosphates
Phosphorylate Ach-ase. Disables ach-ase for a while. Synthetic and extremely toxic.
Malathion: insecticide
Sarin: nerve agent
Atropine
Muscarinic Antagonist. Belladonna Alkaloid. Reversible competitive. Tertiary amine. both CNS and PNS
Used to block respiratory tract secretions prior to surgery. Antidote for cholinergic agonists.
Scopolamine
Muscarinic Antagonist. Belladonna Alkaloid.
Treats motion sickness
Ipatropium
Muscarinic Antagonist. Synthetic quaternary ammonium.
Used to treat COPD and asthma.
Tropicamide
Muscarinic antagonist. Synthetic tertiary amine.
Used to induce mydriasis with cycloplegia (lens muscle paralysis)
Hexamethonium
Nicotinic antagonist. Ganglion blocker.
Was used to treat hypertension in the past.
Tubocurarine
Neuromuscular blocker. Nondepolarizing, competitive antagonist.
Used as an adjuvant in anaesthesia to relax skelet muscle.
Succinylcholine
Neuromuscular blocker. Depolarizing agonist. Leads to rapid receptor desensitization and flaccid paralysis.
Used for rapid endotracheal intubation. Also electroconvulsive therapy.
Botulinum Toxin
Presynaptic acetylcholine release inhibitor.
Treats muscle spasms also used cosmetically for wrinkles.
Epinephrine
Agonist at both alpha and beta receptors. Endogenous catecholamine. At low concentrations mainly acts on b1 and b2. At higher concentrations, a1 effects are more pronounced.
Used for anaphylactic shock, acute asthmatic attacks, cardiac arrest.
Norepinephrine
Agonist at a1, a2 and b1 receptors. Little action on b2 receptors. Endogenous catecholamine.
Used to treat shock because it increases blood pressure via peripheral vasoconstriction.
Isoproterenol
Non-selective Beta agonist. Activates B1 and B2 receptors.
B1 effect- increases heart rate contractility. B2 effect- dilates arterioles in skelet muscle, also bronchodilates. Sys bp stays the same, dia bp falls.
Used in emergencies to stimulate heart rate in bradycardic or heart block patients.