parasympathetic nervous system (cholinergic) Flashcards
1
Q
describe the PNS
A
regulates our “rest and digest” maintenance and promotes balance in the nervous system (opposite of SNS)
2
Q
what physiological effects occur when PNS is activated
A
- dilation of blood vessels
- decreased HR
- increased secretion of digestive enzymes/gastric motility/digestion
- pupil constriction
- contraction of smooth muscle in urinary bladder
- contraction of skeletal muscle
- constriction of bronchioles in lungs and increased lung secretions
3
Q
what is the primary neurotransmitter in the parasympathetic nervous system
A
Acetylcholine (Ach)
4
Q
describe Ach
A
- former in cholinergic nerve endings/located in the brain, ANS, and neuromuscular junctions
- exerts excitatory effects at nerve synapse and NMJ
- inhibits effects at peripheral sites, including cardiac (resulting in a decrease HR)
- Ach synapse is broken down by acetylcholinesterase (AchE)/cholinesterase (choline is taken up by presynaptic neuron to make more Ach)
5
Q
name two cholinergic receptors
A
- nicotinic
- muscarinic
6
Q
where are nicotinic receptors located
A
located in CNS motor nerves and skeletal muscle and adrenal medulla
7
Q
what happens when nicotinic receptors are activated by Ach
A
- causes cell membrane depolarization which produces muscle contraction
- release of epinephrine from adrenal medulla
8
Q
where are muscarinic receptors located
A
located in most internal organs (cardiac, respiratory, GI and GU)
9
Q
what happens when muscarinic receptors are activated by Ach
A
- excites or inhibits
- lungs - bronchioles are constricted
- heart - decrease HR
- GI - increased peristalsis and secretions
- GU - bladder contracts
10
Q
blockage of cholinergic receptors produces…
A
anticholinergic effects
11
Q
describe nicotinic receptors
A
- bind nicotine
- blocked by curare
- linked to ionic channels
- response is brief and fast
- located at neuromuscular junctions, autonomic ganglia, and to a small extent in the CNS
- mediate excitation in target cells
- postsynaptic
12
Q
describe muscarinic receptors
A
- bind muscarine
- blocked by atropine
- linked to 2nd messenger systems through G proteins
- response is slow and prolonged
- found in myocardial muscles, certain smooth muscle, and discrete CNS regions
- mediate inhibition and excitation in target cells
- both pre and post synaptic
13
Q
describe direct acting cholinergic drugs
A
- bind to and activate cholinergic receptors
- highly resistant to metabolism - longer duration of action
- widespread systemic effects: decrease HR, vasodilation = decrease in BP
- increase bladder tone, bronchiole smooth muscle, tone and contractility, salivary secretions, upper sphincter and GI relaxation
- miosis (excessive pupil contriction)
14
Q
why do cholinergic drugs have few drug applications
A
high potential for adverse effects
15
Q
describe indirect acting cholinergic drugs
A
–cause release of the neurotransmitter
- inhibit reuptake or destruction of Ach
- inhibits the action of AchE
- cholinergic effect
- improves skeletal muscle tone and strength
- improves acetylcholine neurotransmission
- either reversible or irreversible acetylcholinesterase inhibitors
16
Q
what are cholinergic drugs used in the treatment of
A
- myasthenia gravis
- alzheimers
- GI and urinary smooth muscle atony
17
Q
name some cholinergic/anticholinergic drug classifications
A
- cholinergic
- parasympathomimetic
- cholinergic agonist
- parasympatholytic
- cholinergic antagonist
- cholinergic blocker
- nicotinic agonist/nicotinic antagonist
- muscarinic agonist/muscarinic antagonist
18
Q
what type of drugs mimic the effect of acetylcholine
A
- parasympathomimetics
- cholinergic agonists
19
Q
what types of drugs block the effects of acetylcholine
A
- parasympatholytics
- cholinergic blockers AKA cholinergic antagonists (anticholinergic)
20
Q
what are some indications for use of cholinergic drugs
A
- urinary retention
- myasthenia gravis diagnosis and treatment
- alzheimers disease
- glaucoma
21
Q
describe myasthenia gravis
A
- chronic autoimmune neuromuscular disease characterized by varying degrees of painless weakness of the skeletal muscles of the body
- breakdown in communication between muscles and nerves
- symptoms may include arm and leg weakness as well as speech and chewing difficulties
22
Q
name two specific medications that are direct acting parasympathomimetics
A
- bethanechol
- carbachol
23
Q
name two specific medications that are indirect parasympathomimetics
A
- donepezil (aricept)
- pyridostigmine
24
Q
describe bethanechol
A
- direct acting parasympathomimetic
- cholinergic agonist/synthetic muscarine stimulant
- increases detrusor tone → contraction → micturition → bladder emptying
25
describe carbachol
- direct acting parasympathomimetic
- cholinergic agonist
- used for _glaucoma tx_
- causes miosis → constriction → fluid excretion → decrease intraocular pressure
26
describe donepezil (aricept)
- indirect acting parasympathomimetic
- selective acetylcholinesterase inhibitor (stops enzyme that breaks down acetylcholine = more acetylcholine)
- used for _treatment of confusion in alzheimer patients_
- increasing levels of available acetylcholine may compensate for loss of functioning cholinergic brain cells
27
describe pyridostigmine
- indirect acting parasympathomimetic
- acetylcholinesterase inhibitor (i.e. anticholinesterase)
- used for _treatment of myasthenia gravis_
28
name side effects of parasympathomimetics
- N/V/D
- involuntary defacation
- increased salivation
- watery eyes
- HA and dizziness
- irregular heartrate, bradycardia
- wheezing and/or breathing problems
- urinary urgency
29
what are some nursing concerns r/t to the side effect of **N/V/D** with parasympathomimetics
- ginger ale
- antiemetic
- fluid volume status (intake and output)
- mobility
30
what are some nursing concerns r/t to the side effect of involuntary defecation with parasympathomimetics
- mobility
- skin integrity
- dignity
31
what are some nursing concerns r/t to the side effect of increased salivation with parasympathomimetics
drooling and dentures fitting
32
what are some nursing concerns r/t to the side effect of watery eyes with parasympathomimetics
infection
33
what are some nursing concerns r/t to the side effect of HA and dizziness with parasympathomimetics
- pain scale
- fall risks (mobility)
34
what are some nursing concerns r/t to the side effect of irregular HB or bradycardia with parasympathomimetics
- telemetry monitoring
- vitals
- fluid volume
35
what are some nursing concerns r/t to the side effect of wheezing and/or breathing problems with parasympathomimetics
- pulse ox
- o2
- bronchodilators
36
what are some nursing concerns r/t to the side effect of urinary urgency with parasympathomimetics
- fall risks
- impulsiveness
- mobility
- skin integrity
- dignity
- bed/chair alarms
37
because cholinergic drugs increase contractility of smooth muscle, they are contraindicated in…
- urinary or GI tract obstruction
- asthma
- peptic ulcer disease
- inflammatory abdominal conditions, recent bowel surgery
- coronary artery disease
- hypertyroidism
- pregnancy
- hepatic or renal impairment
38
what drugs do cholinergic drugs interact with (resulting in contraindication of use)
interact with NSAIDs and theophylline
39
which is use more commonly? parasympathomimetics or parasympatholytics?
parasympatholytics
40
parasympatholytics are medications that block…
the parasympathetic nervous system
| (ie. anticholinergics)
41
name some specific medication examples of parasympatholytics
- atropine
- dicyclomine, propantheline
- meclizine, scopolamine
- glycopyrrolate
- ipratropium, tiotropium
42
describe atropine
- parasympatholytic (anticholinergic)
- emergency medication used for patients with low HR, also used in OR to reduce salivation
- stimulates HR, reduces salivation and GI spasms
- side effects are opposite of cholinergic
43
describe dicyclomine
- parasympatholytic (anticholinergic)
- GI antispasmotic
- used in treatment of IBS
44
describe propantheline
- parasympatholytic (anticholinergic)
- antimuscarinic
- tx of excessive sweating, can be used for GI spasms and cramps, involuntary urination, and IBS
45
describe meclizine
- parasympatholytic (anticholinergic)
- antihistamine
- tx of motion sickness and vertigo
- commonly used medication
46
describe scopolamine
- parasympatholytic (anticholinergic)
- med that blocks Ach, anticholinergic side effect
- can be given as a patch (educate pt on changing patch sites)
- treatment for motion sickness, decreases N and V
47
describe glycopyrrolate
- parasympatholytic (anticholinergic)
- decreases oral secretions on vented pts (used in ICU)
- also can be used for pts with neurological issues
48
describe ipratropium
- parasympatholytic (anticholinergic)
- blocks muscarinic receptors
- opens airways and causes bronchodilation
49
describe tiotropium
- parasympatholytic (anticholinergic)
- anticholinergic for COPD
- works as bronchodilator
50
when cholinergic receptors are blocked it allows…
sympathetic system to dominate
51
what is the goal of parasympatholytics
control symptoms, maintain functional ability, minimize adverse drug effects, and slow disease progressions
52
name some parasympatholytic/anticholinergic drug uses
- GI disorders (antispasmodic in GI system)
- ophthalmic procedures
- cardiac rhythm abnormalities
- pre anesthesia (decrease oral secretions)
- asthma: bronchodilation
- overactive bladder: smooth muscle relaxation (prototype drug: tolterodinem)
53
what are some side effects of parasympatholytics/anticholinergics
- tachycardia, HTN
- CNS stimulation, confusion
- **constipation**, urinary retention
- dry mouth and eyes
- inhibition of sweating
- photophobia (light sensitivity) , blurred vision, increase intraocular pressure
- weakness and dizziness
54
what are some nursing concerns r/t the side effect of tachycardia/HTN with parasympatholytics
- telemetry monitoring
- vitals
- fluid volume
55
what are some nursing concerns r/t the side effect of CNS stimulation and confusion with parasympatholytics
- neuro checks
- safety
56
what are some nursing concerns r/t the side effect of constipation and urinary retention with parasympatholytics
- increase fruits and fiber
- hydration
- I&O
- bladder scan
57
what are some nursing concerns r/t the side effect of dry mouth and eyes with parasympatholytics
- oral care
- saline drops
58
what are some nursing concerns r/t the side effect of inhibition of sweating with parasympatholytics
- temp control
- monitoring
- adjust environmental temperature
59
what are some nursing concerns r/t the side effect of photophobia, blurred vision, increased IOP with parasympatholytics
- dim lighting
- safety
- physician notification
- increased intraocular pressure may manifest as a headache
60
what are some nursing concerns r/t the side effect of weakness/dizziness with parasympatholytics
- safety
- physical and occupational therapy
- increased rounding
61
what are some contraindications of anticholinergic medications
- glaucoma
- GI conditions
- BPH or bladder obstructions
- cardiac arrhythmias, tachycardia, MI history
- renal or hepatic impairment
62
what drugs may interact and cause contraindications of anticholinergics
- antihistamines
- antiparkinson drugs
- MAOIs
- TCAs
63
describe physostigmine
- used to reverse the effects of certain drugs or substances that interfere with nerve muscle communication
- tx of severe anticholinergic toxicity
- ie. anticholinergic drugs such as atropine, scopolamine, belladonna, antihistamines, and some antidepressants, etc
