Anticholinergics

Question 1

2 types of anticholinergics

Answer 1

antimuscarinics and ganglionic blockers

Question 2

action of muscarinic AChR antagonists ( antimuscarinics)

Answer 2

interrupts parasympathetics influence in various tissues

• predominant autonomic tone is parasympathetic ( except: vasculature and sweat glands)
• blocking mAChR-> premits sympathetic influence to become predominant
• effects will be typical of sympathetic activity

Question 3

how do ganglionic blockers act

Answer 3

antagonising the neuronal nAChRs present on the primary ganglionic cell in all autonomic ganglia ( but arent all antagonists)
- effects are sympathetic-like ( not sweat glands or vasculature) due to blocking all autonomic influence

Question 4

pharm effects of prototypical anti-muscarinic atropine - on ocular a

Answer 4

ocular-> 1. relaxes iris sphinicter, symp tone predominates on radial muscle

2. blocks accommodation -relaxes ciliary muscle-> increases tension on ligaments -> flattens lens
3. inhibits lacrimation

Question 5

pharm effects of prototypical anti-muscarinic atropine - on cardiac

Answer 5

1. standard dose increase heart rate and atrioventricular conduction by blocking vagal input
2. very low doses may initially decrease hr by first blocking presynaptic receptors

Question 6

pharm effects of prototypical anti-muscarinic atropine - on respiratory

Answer 6

1. bronchial smooth muscle relaxation and dilation

2. inhibit secretions

Question 7

pharm effects of prototypical anti-muscarinic atropine - on GI

Answer 7

1. decreases lower esophageal muscle tone
2. relaxes GI tones, prolonging intestinal transit time
3. inhibits gastric acid secretions

Question 8

pharm effects of prototypical anti-muscarinic atropine - on urinary

Answer 8

1. relaxes detrusor muscle of the bladder causing urinary retention

Question 9

pharm effects of prototypical anti-muscarinic atropine - on CNS

Answer 9

1, atropine and scopolamine are tertiary amines

2. scopolamine is more sedating than atropine
3. atropine-> 1st stimulation followed by sedating effect
4. high doses can cause confusion and or hallucinations

other: inhibits sweating and could possibly lead to hyperthermia-> causes cutaneous vasodilation

Question 10

major clinical uses of atropine

Answer 10

long lasting mydriasis, pharm path to treat amblyopia, cycloplegia , sinus bradycardia and av block, decrease of salivary and respiratory secretions -> prevents airway obstruction
, intestinal spasms and pain , decrease gastric acid secretions, reversal of muscarinic or AChE inhibitor poisoning, prevention of muscarinic side effects in pts receiving AChE inhibitors and neostigmine to reverse nerve block, mixed with diphenoxylate (opioid agonist) its an anti-diarrheal

Question 11

scopolamine

Answer 11

anti-mus

motion sickness, side effect - drowsiness

Question 12

tropicamide , cyclopentolate, homatropine

Answer 12

anti-mus
fast but short acting mydriatic agent
may be combined with alpha adrenergic agonist

Question 13

ipratropium

Answer 13

anti-mus
quaternary amine-> inhalled
bronchodilator
COPD

TIOTROPIUM- similar but longer acting

Question 14

tolterodine

Answer 14

ant-mus
managment of overactive bladder ( increased freq, nocturia, incontinence)
-fewer side effects_> dry mouth and blurred vision
contraindicated for individuals w/ narrow-angle glaucoma

Question 15

dicyclomine

Answer 15

anti-mus
releaxes intestinal smooth muscle
IBS-> symptoms

Question 16

glycopyrrolate

Answer 16

anti-mus

• low doses preferentially inhibit secretions for preop
• prevents excessive generalized sweating
• prevention of muscarinic side effect in pt receiving neostigmine to reverse neuromuscular block

Question 17

benztropine

Answer 17

relieve extrapyramidal symptoms in parkinson’s or in pt taking antipsychotics

Question 18

adverse actions of anti-mus

Answer 18

dry mouth , blurred vision (mydriasis and cycloplegia) , hot, flushed skin( anhidrosis and cutaneous vasodilation) constipation difficulty in urinating, tachycardia , CNS effects : confusion, sedation, delirium

“dry as a bone, red as a beet, hot as a hare, blind as a bat, mad as a hatter”

Question 19

classes of drugs which some members have antimus activity

Answer 19

antihistamines - diphenhydramine
antidepressants - tricyclics - amitriptyline
phenothiazine antipsychotics- chlorpromazine

Question 20

depolarizing ganglionic blockers

Answer 20

nicotinic agonist

• act by initially activating the ganglionic nACh receptors - followed by receptor blockade resulting from persistent depolarization
• organophosphate cholinesterase inhibitors may cause some degree of depolarizing ganglionic block

Question 21

nicotine

action, basic pharm effects

Answer 21

1. stimulation of autonomic ganglia followed by ganglionic blockade ( dose-dependent)
2. stim of adrenal medulla (possible significant secretion of epi)
3. stim of CNS: altering response, change in respiration

Question 22

symptoms of nicotine toxicity

Answer 22

GI-> nausea, vomiting, salivation, diarrhea
cardio-> tachy/brady, hypo/hypertension, arrhythmia
CNS-> lethargy, confusion, seizures, coma
peripheral nervous system-> diaphoresis
muscles-> tremors, fasciculations, weakness, paralysis
endocrine-> increase epi release

Question 23

non-depolarizing ganglionic blockers

Answer 23

act by blocking nACh receptors in all autonomic ganglia

• reduce the most prominent autonomic tone in each organ
• curare compounds use in the past as NM blockers cause non-depolarizing ganglionic blocks as well

Question 24

hexamethonium (C6)

Answer 24

antagonist at nAChR at ganglion

• 1st effective antihypertensive (not used anymore)
• poor absorption and autonomic side effects led to discontinuation of its use

Question 25

mecamylamine

Answer 25

antagonist at nAChR at ganglion - can be used to improve GI absorption - recent interest in its use for tourette syndrome

Question 26

effects of ganglionic blockade on and predom tone 1. arterioles 2. veins 3. heart 4. iris 5. ciliary muscle 6. GI tract 7. urinary bladder 8. salivary glands 9. sweat glands

Answer 26

1. arterioles -s-vasodilation and increase peripheral blood flow 2. veins -s- dilation, peripheral pooling , decrease return decrease CO 3. heart- p- tachy 4. iris-p- mydriasis 5. ciliary muscle-p-cycloplegia (loss of accomodation) 6. GI tract-p-decrease tone and motility, constripation 7. urinary bladder- p- urinary retention 8. salivary glands -p-xerostomia 9. sweat glands -s- anhidrosis ( cholinergic)

Question 27

atropine action selected uses

Answer 27

antagonist at all mAChRs | revere muscarinic or AChE inhibitor poisoning, long lasting pupil dilation and antidiarrheal

Question 28

scopolamine | action and uses

Answer 28

antagonist to all mAChRs motion sickness

Question 29

tropicamide cyclopentolate homatropine

Answer 29

antagonist to all mAChRs - hort acting pupil dilation

Question 30

Ipratropium tiotropium action and uses

Answer 30

antagonist at mAChRs quaternary amine ; local action newer alt: tiotropium COPD

Question 31

tolterodine action and uses

Answer 31

antagonist at bladder mAChRs overactive bladder

Question 32

dicyclomine | action and uses

Answer 32

antagonist at GI mAChRs irritable bowel

Question 33

Glycopyrrolate action and uses

Answer 33

antagonist at mAChR secretion, sweating, muscarinic overshoot after cholinesterase inhibition

Question 34

benztropine | action and uses

Answer 34

lipid soluble mAChR antagonist extra pyramidal effects of parkinsons

Question 35

mecamylamine | action and uses

Answer 35

antagonist at nAChR at ganglion improves GI absorption , tourette syndrome

Question 36

hexamethonium action and uses

Answer 36

antagonist at nAChR at ganglion prevents baroreceptor reflex