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Flashcards in Cholinergics Deck (86)
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1
Q

Hemicholinium receptor/mechnism

A

Blocks choline transporter CHT1 preventing uptake and synthesis of acetylcholine

Used for research

2
Q

Vesamicol receptor/mechanism

A

Blocks the vesicular ACh-H+ antiporter VAChT preventing storage of ACh

Used for research

3
Q

Botulinum Toxin receptor/mechanism

A

Prevents synaptic vesicle fusion inhibiting ACh release (synaptobrevin)

Used in local injection; conditions with excess muscle tone (blepharospasm); wrinkles, HA and pain

4
Q

Neuromuscular blockers drugs

A

Tubocurarine and Succinylcholine

5
Q

Tubocurarine receptor/mechanism

A

Non depolarizing
Binds to Nm->competitive inhibition
Prevents depolarization

6
Q

Tubocurarine indication/effect

A

Anesthesia->muscle weakness and flaccid paralysis

Action can be overcome by AChE inhibitors such as neostigmine or edrophonium

7
Q

Tubocurarine PK

A

Minimal oral absorption so need to be IV
Poor membrane penetration
Doesn’t cross BBB

8
Q

Tubocurarine adverse

A

May cause histamine release

May bind M receptors

9
Q

Succinylcholine receptor/mechanism

A

Depolarizing
Activates Nm causing depolarization -> transient disorganized contraction -> desensitization followed by flaccid paralysis

10
Q

Succinylcholine indication/effect

A

Useful for ET intubation

Electroconvulsive therapy

11
Q

Succinylcholine PK

A

continuous IV infusion

Rapid hydrolysis by plasma cholinesterase
Rapid onset (1m) and brief duration (5-10m)
Not metabolized effectively at the synapse

12
Q

Succinylcholine adverse

A

Malignant hyperthermia an autosomal dominant disorder -> excess release of calcium from the SR; usually when combined with a halogenated anesthetic (Tx dantrolene)

13
Q

Mecamylamine, Trimethaphan, Hexamethonium receptor/mechanism

A

Antagonize nicotinic receptors in both parasympathetic and sympathetic autonomic ganglia

14
Q

Mecamylamine, Trimethaphan, Hexamethonium effects

A

Arterioles and veins are under predominant sympathetic control (adrenergic) -> dilation, hypotension, etc alpha 1

Block parasympathetics at the heart, iris and ciliaris muscle -> tachycardia, mydriasis, and cycloplegia (far vision)

GI, urinary bladder and salivary gland lose parasympathetics -> reduced motility, secretions; urinary retention, xerostomia (dry mouth)

Sweat glands lose sympathetics -> anhydrosis

15
Q

Mecamylamine, Trimethaphan, Hexamethonium adverse

A
Vasodilation
Venodilation
Hypotension
Tachycardia
Mydriasis
Decreased GI/urinary motility
Xerostomia
Anhydrosis
16
Q

Mecamylamine, Trimethaphan, Hexamethonium other

A

Historically used to treat HTN, but have been replaced due to many undesirable effect

Dirty drugs

17
Q

Pralidoxime effect

A

Regenerate cholinesterase after organophosphate poisoning (before aging)

18
Q

Pralidoxime indication

A

not used for carbamate poisoning which is reversible and short lived

19
Q

Pralidoxime other

A

Positively charged; it does not enter the CNS -> not effect on central sx

20
Q

Tolterodine effect

A

Tertiary amine

Relaxes smooth muscle

21
Q

Tolterodine indication

A

overactive bladder

22
Q

Muscarinic antagonists

A
Atropine
Scopolamine
Ipratropium and Tiotropium
Homatropine, Cyclopentolate, Tropicamide
Benztropine, Trihexyphenidyl
Glycopyrrolate
Tolterodine
23
Q

Glycopyrrolate indication

A

Oral: inhibition of GI motility
Parenteral: prevent bradycardia during surgery

24
Q

Benztropine and Trihexyphenidyl Effects

A

Restore balance of input after loss of dopaminergic neurons in the nigrostriatal pathway

25
Q

Benztropine and Trihexyphenidyl Indication

A
Parkinsonism
Extrapyramidal effects ( i.e. drug induced movement disorders) of antipsychotic drugs (D2)
26
Q

Benztropine and Trihexyphenidyl PK

A

tertiary amines are able to enter the CNS

27
Q

Homatropine, Cyclopentolate, Tropicamide effects

A

Mydriasis and cycloplegia - preferred over atropine because of shorter duration of action

28
Q

Homatropine, Cyclopentolate, Tropicamide PK

A

tertiary amines are able to enter the CNS

29
Q

Ipratropium, Tiotropium effects

A

Bronchodilation (M3)

30
Q

Ipratropium, Tiotropium indication

A

Inhalation Tx of *COPD and adjuvant therapy in asthma

31
Q

Scopolamine effects/indication

A

DOC for motion sickness

Blocks short term memory (anesthetic procedures)

32
Q

Scopolamine other

A

Belladonna Alkaloids-Tertiary amines

Greater and longer duration of action in the CNS than atropine

33
Q

Atropine effects

A

Eye: mydriasis, unreactive to light, cycloplegia (paralysis of ciliaris muscle causing loss of accommodation and adaptation)
GI: antispasmodic; decreases motility (HCl production not affected)
Urinary: decreases hypermotility
CVS: low dose -> bradycardia (presynaptic M2)
moderate to high dose-> tachycardia (atrial M2)

Secretions from salivary, sweat and lacrimal glands are blocked (may increase body temperature)

34
Q

Atropine indication

A

Antisialagogue prior to surgery decreases respiratory secretions
Increased HR or Decrease AV block due to excessive vagal tone
OD of cholinergic drugs (farmer spraying parathion)
Death cap mushroom poisoning
Alleviate the muscarinic side effects of AChE drugs

35
Q

Atropine PK

A

readily absorbed, partially metabolized by the liver, eliminated primarily in the urine

36
Q

Muscarinic antagonists contraindications/adverse effects

A

“Atropine flush” due to cutaneous vasodilation (especially in upper body)

Anti-PS ->dry mouth, blurred vision, sandy eyes, tachycardia, constipation

CNS: restlessness, confusion, hallucinations, delirium, depression -> shock and death

Elderly patients with angle closure glaucoma -> exacerbation and blindness

Use with caution in patients with BPH ->decrease detrusor contraction can cause urinary retention

Low levels may cause bradycardia and sedation

High levels may cause tachycardia and CNS hyper excitation (delirium, hallucinations, and seizures)

37
Q

AChE Inhibitor drugs

A
Edrophonium (Tensilon)
Physostigmine
Neostigmine
Pyridostigmine
Echothiophate (obsolete)
Malathion, Parathion
Tabun, Sarin, Soman
Tacrine, Donepezil, Rivastigmine, Galantamine
38
Q

Tacrine, Donepezil, Rivastigmine, Galantamine indication

A

Orally used

Alzheimer’s disease

39
Q

Tabun, Sarin, Soman mechanism

A

Phosphorylate active site (extremely stable)

Ageing-strengthening of the bond making it much more difficult to reverse

40
Q

Malathion, Parathion mechanism

A

Phosphorylate active site (extremely stable)

Ageing-strengthening of the bond making it much more difficult to reverse

41
Q

Echothiophate mechanism

A

Phosphorylate active site (extremely stable)

Ageing-strengthening of the bond making it much more difficult to reverse

42
Q

Echothiphate indication

A

Chronic angle glaucoma

NOT liposoluble-> doesn’t enter CNS

43
Q

Malathion, Parathion effects

A

Activated by conversion to oxygen analogs in the body

44
Q

Malathion, Parathion indications

A

insecticides (farmer spraying his field…)

45
Q

Malathion, Parathion PK

A

Fully distributed (including CNS)

46
Q

Malathion, parathion adverse

A

Organophosphate overdose treated with atropine or Pralidoxime have to give before ageing

CNS toxicity

47
Q

Tabun, Sarin, Soman adverse

A

Organophosphate overdose treated with atropine or Pralidoxime have to give before ageing

CNS toxicity

48
Q

Tabun, Sarin, Soman effects

A

Nerve agents - most potent synthetic toxic agents known

Used for terrorism

49
Q

Pyridostigmine indication

A

Treatment of Myasthenia gravis (most common)

50
Q

Pyridostigmine adverse

A

CNS toxicity

51
Q

Neostigmine mechnism

A

Covalent bond with AChE and ButyrylChE

52
Q

Pyridostigmine mechanism

A

Covalent bond with AChE and ButyrylChE

53
Q

Physostigmine mechanism

A

Covalent bond with AChE and ButyrylChE

54
Q

Physostigmine chemical

A

carbamate - tertiary amine

Crosses BBB

55
Q

Neostigmine and Pyridostigmine chemical

A

Carbamates - QAC - does not enter CNS

56
Q

Edrophonium (Tensilon) chemical

A

simple alcohol QAC

57
Q

Edrophonium (Tensilon) mechanism

A

Reversible binding to active site of AChE and butyrylcholinesterase

58
Q

Neostigmine indications

A

Reversal of NMJ block produced by non depolarizing muscular blockers i.e. tubocurarine

Second line treatment for myasthenia gravis
Does not enter the CNS
Prevention and Tx of urinary retention

59
Q

Neostigmine adverse

A
Hypotension
Salivation, flushing
Abdominal pain
Nausea, diarrhea
Bronchospasm
60
Q

Physostigmine indications

A

Tx for anticholinergic overdose

Intestinal or bladder atony

61
Q

Physostigmine adverse

A

High dose -> convulsions**, skeletal muscle paralysis, bradycardia

Contraindicated in suspected TCA overdose -> aggravates depression of cardiac conduction (TCA’s block sodium channels)

62
Q

Edrophonium indication

A

Diagnosis of Myasthenia gravis (rapid increase in muscle strength after dose)

Reverse neuromuscular block produced by non depolarizing muscular blockers (can be used for recovery after surgery)

63
Q

AChE inhibitor effects

A

CNS: convulsion, coma, respiratory arrest

PS action in the eye, respiratory, GI and urinary tracts

CVS: -ve chronotropic and inotropic effects -> decreased CO and hypotension

NMJ: increased contraction in weak muscles

64
Q

Acetylcholine Receptor

A

N and M

65
Q

Acetylcholine mechanism

A

Binding to M receptor induces PS activity

Nicotinic effects once M receptors are blocked by atropine (high dose)

66
Q

Acetylcholine Effects

A

M: parasympathetic and sympathetic activity, sweat glands

CVS: M3 vasodilation and reflex tachycardia at small doses; hypotension and bradycardia at higher doses

N: stimulate all autonomic ganglia, secretion of Epi from adrenal medulla; skeletal muscle increase HR, BP, etc.

67
Q

Acetylcholine indication/use

A

Small iv-> drop BP with tachycardia

Virtually no use except
Cataract surgery -> rapid miosis

68
Q

Cholinergic agonist adverse

A

Muscarinic syndrome
Generalized cholinergic stimulation -> sweating, miosis, flushing, salivation, bradycardia, hypotension, bronchospasm

DUMBBELLSS-> 
Diarrhea
Urination
Miosis
Bradycardia
Bronchoconstriction
Emesis
Lacrimation
Lethargy
Salivation
Sweating
69
Q

Bethanechol receptor

A

M

70
Q

Bethanechol mechanism

A

Parasympathetic

71
Q

Bethanechol effects

A

Activates bowel and bladder

72
Q

Bethanechol indication/use

A
Urinary retention (post-surgical postpartum)
Hypotonic, myogenic, neurogenic bladder ... atony

Ileus, gastroparesis, congenital megacolon

Cannot cross BBB

73
Q

Carbachol receptor

A

M and N

74
Q

Carbachol mechanism

A

parasympathetic

75
Q

Carbachol effects

A

Miosis and contraction of ciliaris muscle

76
Q

Carbachol indication/use

A

Intraocular surgery
Glaucoma - decrease intraocular pressure (use pilocarpine first)

External use only

77
Q

Methacholine receptor

A

M and little N

78
Q

Methacholine indication/use

A

diagnosis of bronchial airway hyperreactivity in patients without clinically apparent asthma

79
Q

Pilocarpine receptor

A

Partial M

tertiary amine

80
Q

Pilocarpine effects

A

Contraction of ciliaris

Secretion from sweat, salivary, lacrimal and bronchial glands

81
Q

Pilocarpine indication/use

A

Acute close-angle glaucoma
Open angle glaucoma -> 2nd line after timolol
Included in the regimen for close angle glaucoma with: timolol, apraclonidine, acetazolamide, and mannitol or glycerol

82
Q

Pilocarpine adverse

A

CNS disturbances
Sweating
Salivation

83
Q

Nicotine receptor

A

Nn>Nm

Tertiary amine

84
Q

Nicotine mechanism/effect

A

Low dose: ganglion deploarization in both sympathetic and parasympathetic
CVS: sympathomimetic due to catecholamine release
GI and UG: parasympathomimetic -> n/v/d, voiding, salivary and bronchial secretions

High dose: ganglion blockade due to prolonged depolarization (desensitization)

85
Q

Nicotine indication/use

A

smoking cessation therapy

86
Q

Nicotine adverse

A

Acute nicotine poisoning: nausea, salivation, abdominal pain, vomiting, diarrhea, cold sweat, confusion, etc.
Hypotension with a rapid and weak pulse
Can lead to death respiratory arrest (central or peripheral)