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42 Cards in this Set
- Front
- Back
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Botox
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Interferes with membrane docking proteins that mediate vesicular fusion of Ach vesicles (↓ Ach)
Treats spastic muscles (strabismus, dystonias, tics, wrinkles) |
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Muscarinic Receptor Subtypes
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M 1,3,5 = activate Gq and are stimulatory
M 2,4 = activate Gi and are inhibitory M1 = somatic nerves (at NMJ) M2 = cardiac mm M3 = glands, smooth mm, endothelium M4,5 = CNS |
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What does methylation of a muscarinic agonist do to its mode of action?
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- causes it to be more specific to Muscarinic receptors
- confers slight resistance to cholinesterase to prolong its action |
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What does Caramyl substitution of a muscarinic agonist do to its mode of action?
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confers total cholinesterase resistance for VERY prolonged action
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Acetylcholine
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Muscarinic agonist
choline ester |
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Bethanechol
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Muscarinic agonist
choline ester Methylated and carbamyl substituted (Ach + CH3 + NH2) to give high M receptor specificity and high resistance to cholinesterase |
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Carbachol
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Muscarinic agonist
choline ester Carbamyl substituted (Ach + NH2) to give high resistance to cholinesterase |
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Methacholine
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Muscarinic agonist
choline ester Methylated (Ach + CH3) to give high M receptor specificity and slight resistance to cholinesterase |
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Pilocarpine
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Muscarinic agonist
Naturally Occuring Alkaloid selective for M receptors Cholinesterase resistant |
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Muscarine
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Muscarinic agonist
Naturally Occuring Alkaloid selective for M receptors |
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Arecoline
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Muscarinic agonist
Naturally Occuring Alkaloid selective for M receptors Cholinesterase resistant |
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Systemic effects of Muscarinic Agonists
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Occular: Miosis, Loss of accomodation (only see near objects)
CV: bradycardia, vasodilation (stimulates NO release) Resp.: Bronchoconstricition, ↑ mucous secretions GI: Sailorrhea (slobbery), ↑gastric acid, ↑ gastric motility + relaxed spincters = defecation UG: contracts detrusor and relaxes trigone and sphincter = urination CNS: no effect (can't cross BBB) |
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What kind of drug would you use to Sjogrens Syndrome (autoimmune attack of salivary glands) or radiation-induced dry mouth?
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Muscarinic Agonist (increases salivation)
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What kind of drug would a surgeon inject into the bowel post-operatively to prevent ileus?
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Muscarinic agonists (increases gastric motility and relaxes sphincters to promote defecation)
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Cholinesterase Inhibitors
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cholinomimetic drugs that ↓ the breakdown of choline esters (including Ach) to ↑ their concentration at synapses
. Same effect as muscarinic agonists at Muscarinic synapses . Cause mm fasiculations/contraction at Nicotinic synapses . Cause Hypertension at Ganglionic synapses |
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Edrophonium
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Cholinesterase Inhibitor
Short-Acting - Used to diagnoses Myasthenia Gravis (injection causes immediate relief of symptoms) - Used to differentiate between a Myasthenia crisis (due to a rise in anti-AchR antibodies from drug failure) vs Cholinergic crisis (due Ach toxicity-induced depolarizing block from too much drug) →→ If injection relieves symptoms = myasthenia crisis |
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Neostigmine
(and Pyridostigmine) |
Cholinesterase Inhibitor
Intermediate-Acting - Treatment for Myasthenia Gravis (prolongs Ach action at the NMJ) |
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Physostigmine
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Cholinesterase Inhibitor
Intermediate-Acting - Treats Atropine (competitive muscarinc antagonist) poisoning |
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Isoflurophate
Echothiophate Organic pesticides and nerve gas |
Cholinesterase Inhibitor
Long-Acting - irreversible *treat overdose with atropine + slow infusion of pralidoxmine |
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What kind of drug would you use to treat Alzheimers?
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Cholinesterase Inhibitor - Tacrine (prolong action of Ach in brain synapses)
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Depolarizing Block
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results from too much Nm receptor activation, causing Nav channels to become refractory leading to flaccid paralysis
Caused by Ach, Nicotine, Succinylcholine stimulation or too much myasthenia gravis drugs (cholinerigic crisis) |
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What adverse effects are unique to cholinesterase inhibitors
(i.e. what effects do AchE inhibs. have that muscarinc agonists do not?) |
MM fasiculation and tremor, flaccid paralysis and respiratory collapse from depolarizing block
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Systemic effects of Muscarinic Antagonists
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Occular: Mydriasis, Loss of accomodation (only see far objects)
CV: tachycardia Resp.: Bronchodilation, ↓ mucous secretion, ↓ ciliary clearance of mucous GI: xerostomia (dry mouth), ↓ gastric acid, ↓ gastric motility + contracted spinchters = constipation UG: relaxes detrusor + contracts trigone to retain urine CNS: crosses BBB → sedation, antiemisis, amnesisa, hallucinations (@high doses) Symp: ↓diaphoresis (no sweat) |
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Atropine
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Muscarinic Antagonist
Cholinesterase inhibitor antidote, antiemetic, anti-diarrhea |
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Ipraptropium
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Muscarinic Antagonist
COPD treatment |
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Scopolamine
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Muscarinic Antagonist
motion sickness treatment |
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What kind of drug would you use as a surgery adjunct to dry airways for ventilation and cause surgical amnesia?
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Muscarinic Antagonist
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What kind of drug would you use to treat a resting tremor caused by Parkinson's disease?
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Muscarinic Antagonist
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What kind of drug would you use to treat motion sickness?
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Muscarinic Antagonist
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Muscarinic Antagonist Overdose Toxicity symptoms
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Dry as a bone (no sweating)
Hot as a furnace (no sweating = no cooling) Red as a beet Mad as a hatter (hallucinations and amnesia) Blind as a bat (Mydriosis and only able to see far away objects) |
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Ganglionic Blockers
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Channel blockers (prevent Na+ from entering channel pore) for Nn receptors in ANS, causing effects opposite of the effector organs' predominant tone
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What is the predominant tone and resulting effects of ganglionic blocker for the following effector organs:
GI/UG, Cardiac, Vasculature, Upper Resp, Iris, Sweat glands, salivary glands |
GI/UG: Parasymp → relax GI muscle (ie ↓ motility) to cause constipation
Cardiac: Parasymp → tachycardia Vasculature: Symp → vasodilation Upper Resp: Symp → bronchodilation Iris: Parasymp → cycloplegia and mydriosis Sweat Glands: Symp → Anhydrosis Salivary Glands: Parasymp → dry mouth |
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Hexamethonium
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Ganglionic blockers
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Non-Depolarizing Neuromuscular-Blocking Drugs
In what order do they effect mm? |
competitive antagonists of Nm receptors that prevent the depolarization of mm cells, and at high doses block Na+ channels of receptor
paralyzed small mm first, then large mm of limbs, and finally the diaphragm (reversal of effects in opposite order) |
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Adverse effects of Non-Depolarizing Neuromuscular-Blocking Drugs
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Hypotension (via histamine release), tachycardia, ganglionic blockade at high doses, prolonged NMJ blockade
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Depolarizing Neuromuscular-Blocking Drugs
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NMJ agonists of Nm receptors that initially cause depolarization (causing a brief, intense, uncoordinated mm contraction) followed by a partial repolarization and refractory state of channel (seen as flaccid paralysis)
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Adverse Effects of Depolarizing Neuromuscular-Blocking Drugs
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prolonged NMJ blockade, HYPERKALEMIA, ↑ intraoccular pressure, ↑ intragastric pressure, mm pain, malignant hyperthermia
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Succinyl Choline
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Short-acting Depolarizing NMJ-Blocking Drugs
Used for emergency intubation |
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Vecuronium
Gallamine |
Intermediate-acting (20-35 min) Non-Depolarizing NMJ-Blocking Drugs
used for short surgical procedures to paralyze diaphragm for ventilation |
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Tubocurarine
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Long-acting (35min+) Non-Depolarizing NMJ-Blocking Drugs
used for long surgical procedures to paralyze diaphragm for ventilation |
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How would you reverse the effects of a neuromuscular-blocking drug?
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1. AchE Inhibitor (neostigmine or pyridostigmine) to ↑ Ach
*except for Mivicurium 2. Sugammadex - chelates drug and removes the inactive complex in urine |
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Mivicurium
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Non-depolarizing NMJ-Blocker short-acting
*Can't be treated with AchE Inhibitors due to it being metabolized by AchE |
