2. ANS drugs Flashcards

1
Q

Choline enters from ECF by sodium-dependent membrane carrier( blocked by

A

hemicholinium

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2
Q

Acetylcholine(Ach) is transported from cytoplasm to storage vesicles by antiporter(to be blocked by

A

vesamicol

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3
Q

ACh release can be blocked by

A

botulinum toxin

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4
Q

Dopamine is transported into vesicle by high-affinity carrier mechanism(inhibited by

A

reserpine

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5
Q

Release of norepinephrine can be blocked by

A

guanethidine and bretylium

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6
Q

Reuptake 1of NE is the most important mechanism for termination which can be blocked by

A

cocaine and tricyclic antidepressants

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7
Q

Cholinomimetic drugs divided into

A

Divided into: cholinoceptor-activating(direct) and cholinesterase inhibiting drugs(indirect)

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8
Q

Direct-acting drugs can be divided on the basis of chemical structure into:

A

Esters of choline, and
Alkaloids

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9
Q

Esters of choline:

A

acetylcholine, methacholine, carbachol, bethanechol

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10
Q

ACh has virtually no therapeutic applications because it

A

is hydrolyzed rapidly by AChE and pseudocholinesterases and diffuseness of its actions

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11
Q

Alkaloids:

A

muscarine, pilocarpine, nicotine, and lobeline

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12
Q

Esters of choline are
hydrophillic or hydrophobic

A

hydrophillic so not absorbed rapidly

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13
Q

Tertiary alkaloids are well absorbed from most sites of administration except

A

muscarine

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14
Q

ACh released from activation of parasympathetic NS can activate:

A

1) muscarinic receptors on effector organs,

2) interact with muscarinic receptors on nerve terminals to inhibit release of NTs

3) ACh can also activate nicotinic receptors

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15
Q

organ system effects og cholinomimetics

A

eye - miosis/ contaction which facilitate flow of aqueous humour

CVS- decrease in heart rate direct effect
increase reflex effect
decrease peripheral resistance

respa- broncho constriction

GIT - increased motility

GUT - increase voiding

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16
Q

Indirect-acting cholinomimetics types

A

1) Simple alcohols bearing quaternary ammonium group e.g. edrophonium
2) Carbamic acid esters of alcohols bearing
tertiary or quaternary ammonium groups e.g. physostigmine, neostigmine, pyridostigmine, ambenonium…)
3) Organic derivatives of phosphoric acid (organophosphates) e.g. isoflurophate, echothiophate,malathion, parathion,sarin,tabun…)

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17
Q

based on absorption best to worst

A

physostigmine well absorbed
organophosphates except echthiophate well absorbed
Quaternary amines poorly absorbed

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18
Q

Binding to the active site of the enzyme is

A

reversible for edrophonium and carbamic acid esters of alcohols bearing tertiary or Quaternary ammonium compounds(reversible AChE inhibitors)

irreversible for organophosphates

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19
Q

The process termed as aging

A

(breaking of one of oxygen-phosphorus bonds of the inhibitor) further strengthens the phosphorus-enzyme bond

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20
Q

antidote for aging or organophosphate poisoning

A

oxime regenerators or cholinesterase regenerators
split enzyme phosphate bond before aging

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21
Q

duration of action shortest to longest

A

edrophonium short
organophospahte long

22
Q

clinical use
eye
git
gut
skeletal
anti muscarnic drug intoxication
CNS

A

treatment of glaucoma open angle

post op ileus congenital megacolon
bethanecol

urine retention
bethanechol and neostigmine

myastenia gravis- edrophonium for diagnosis
-carvamic acid estres for treatment

physostigmine

alzheimers

23
Q

Cholinoceptor antagonists are divided into:

A

muscarinic, and
nicotinic antagonists

24
Q

muscarnic antagonists divided into

A

teritiary ammonium and quaternary ammonium cpds

25
tertiary amines include
atropine, scopolamine, dicyclomine, pirenzepine, benztropine,
26
Quaternary ammonium agents:
propantheline, glycopyrrolate, ipratropium, tiotropium….
27
Tertiary amines or quats well absorbed from the GIT and conjuctival membranes
teritiary
28
Mechanism of action of anti muscarnics
atropine causes reversible blockade of the actions of ACh at muscarinic receptors They compete for the common binding site Atropine does not distinguish between sub types of muscarinic receptors
29
..............exhibit relative selectivity
pirenzepine for M1
30
organ system effects eye cvs respa git gut sweat glands CNS
eye mydriasis and cycloplegia cvs tachycardia and block vasodilation respa bronco dilation git reduced motilty and secretion gut relaxed detrusor sweat glands no sweat atropine fever cns sedative effect
31
clinical use cns eye git cvs respa gut
cns parkinsons -benz and trihex motion sickness- scopolamine eye measuring refractive error - tropicamide git treat pud and diarrhea cvs treat bradycardia respa treat asthma - ipratropine and tiotro Gut treat urinary urgency
32
Nicotinic rec. antagonists are divided into:
Ganglion blockers Neuromuscular blockers
33
Ganglion blockers include
hexamethonium, mecamylamine, trimethaphan
34
organ system effects cns cvs eye git gut sweat gland
cns mecamylamine cross bbb and cause sedation cvs tachycardia reduce bp eye mydryasis and cycloplegia git reduced motility gut urine retention impaired sex function sweat gland ihibited
35
therapeutic use of gang. blockers
limited used for short term bp lowering
36
2 types of NM blockers
depolarizing and non depolarizing
37
non depolarizing based on time effective
long term tubucurarine pancuronium dexacurium intermediate vecucorium atracorium short mivacorium
38
depolarizing blockers
succinylcholine decamethonium
39
3 types of sympatomimetic drugs
direct indirect mixed
40
direct sympatomimetics
epinephrine, norepinephrine, phenylephrine. Isoproterenol, salbutamol, clonidine,.
41
indirect symp mimetics
amphetamine tyramine
42
Mixed-acting
ephedrine
43
based on selectivity alpha 1 selective
phenylephrine,methoxamine
44
Alpha2 selective: ..
clonidine, methylnorepinephrine
45
Beta1 selective:
dobutamine
46
Beta2 selective:
albuterol(salbutamol), terbutaline, salmeterol..
47
organ system effect cvs eye respa git gut exocrine glands metabolism cns
cvs tachycardia increase bp alpha 1 and 2 vasoconstrict b2 vasodilate eye mydriasis respa bronchodilate git decrease motility gut yterus alpha and beta 1 relax'bladder and sphinicter retention
48
Adrenoceptor blocking drugs divided into
Alpha rec antagonists- block alpha Beta rec. antagonists-block beta
49
Alpha rec antagonists divided into based on selectivity
Alpha1 selective blockers: prazosin, doxazosin, terazosin, tamsulosin Alpha2 selective blockers: yohimbine non selective phentolamine, phenoxybenzamine
50
Alpha1 antagonists are given
orally Prazosin is the prototype Doxazosin and terazosin are congeners of prazosin have higher bioavailability and longer half-lives
51
Beta receptor antagonists divided based on selectivity
Non-selective antagonists: propranolol, nadolol, pindolol, timolol, sotalol,labetalol,etc Beta1 selective antagonists: metoprolol(prototype), acebutolol, atenolol, betaxolol, bisoprolol, celiprolol,esmolol ABEAM partial agonists activity: acebutolol, celiprolol, pindolol,etc
52
all beta blockers are reversible or irreversible
reversible