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Flashcards in Mod 5 Adrenergic drugs Deck (21):
1

Cholinergic Drugs: Definition

Drugs that stimulate the parasympathetic
nervous system (PSNS)
Th PSNS is the opposing system to the SNS

2

Cholinergic Drugs: Definition
(cont’d)

Also known as cholinergic agonists or
parasympathomimetics
Mimic the effects of the PSNS
neurotransmitter: acetylcholine (Ach)

3

Cholinergic Receptors

Two types, determined by:
Location
Action once stimulated
Nicotinic receptors
Muscarinic receptors

4

Nicotinic Receptors

Located in the ganglia of both the
PSNS and SNS
Named “nicotinic” because they can be
Namedae nicotinic nicotinic because because theye can can bee
stimulated by the alkaloid nicotine

5

Muscarinic Receptors

Located postsynaptically in the effector
organs of the PSNS
Smooth muscle
Cardiac muscle
Glands
Named “muscarinic” because they can be stimulated by the alkaloid muscarine

6

Mechanism of Action

Directrec--acting cholinergic agonists acting cholinergic agonists
Bind to cholinergic receptors, activating them
Indirect--acting cholinergic agonists
Inhibit the enzyme acetylcholinesterase, which breaks down Ach
Results in more Ach available at the receptors

7

Indirect Indirect--Acting (Cholinesterase Acting (Cholinesterase Inhibitors)

Reversible
Bind to cholinesterase for a period of
minutes to hours
Irreversible
Bind to cholinesterase and form a permanent
covalent bond
The body must make new cholinesterase

8

Drug Effects

Effects seen when the PSNS is stimulated
The PSNS is the “rest and digest” system

9

Drug Effects (cont’d)

“SLUDGE”
Salivation
Lacrimation
Urination
Diarrhea/defecation
Gastrointestinal cramps
Emesis

10

Drug Effects (cont’d)

Stimulate intestine and bladder
Increased gastric secretions
Increased gastrointestinal motility
Increased urinary frequency
Stimulate pupils
Constriction (miosis)
Reduced intraocular pressure
Increased salivation and sweating

11

Drug Effects (cont’d)

Cardiovascular effects
Decreased heart rate
Vasodilation
Respiratory effects
Bronchial constriction, narrowed airways

12

Drug Effects (cont’d)

At recommended doses, the cholinergics
primarily affect the muscarinic receptors
At high doses, cholinergics stimulate the
nicotinic receptors

13

Drug Effects (cont’d)

Desired effects: from muscarinic receptor
stimulation
Many undesirable effects are due to
Manyan undesirable undesirable effects effects are are dueue too
stimulation of the nicotinic receptors

14

Indications

Directrec--acting drugs acting drugs
Reduce intraocular pressure
Useful for glaucoma and intraocular surgery
AAcecettyyllcchhoolilinene
• Carbachol
• Pilocarpine
Topical application because of poor oral
absorption

15

Indications (cont’d)

Directrec--acting drug acting drug—bethanechol bethanechol
Increases tone and motility of bladder and GI tract
Relaxes sphincters in bladder and GI tract allowing
Relaxes Relaxes sphincters sphincters inn bladder bladder and an GI tractrac, , allowing allowing
them to empty
Helpful for postsurgical atony of the bladder
and GI tract

16

Indications (cont’d)

Directrec--acting drug acting drug—cevimeline (Evoxac) cevimeline (Evoxac) Used to treat xerostomia (dry mouth) resulting from
Sjögren’s syndrome gren’s syndrome

17

Indications (cont’d)

Indirect Indirect--acting drugs acting drugs Cause skeletal muscle contractions
Used for diagnosis and treatment of
myasthenia gravis
myasthenia gravis
Used to reverse neuromuscular blocking drugs
Used to reverse anticholinergic poisoning (antidote)
Examples: physostigmine, pyridostigmine

18

Indications (cont’d)

Indirect Indirect--acting anticholinesterase drugs Used for treatment of mild to moderate
Alzzheeimerer’’s disease
• donepezil (Aricept)
• tacrine (Cognex)
• galantamine (Razadyne)
• rivastigmine (Exelon)

19

Indications (cont’d)

memantine (Namenda)
Not a cholinergic drug
Noto aa cholinergic cholinergic drugru
Also used in the treatment of Alzheimer’s disease

20

Adverse Effects

Adverse effects are a result of overstimulation of the
PSNS
Cardiovascular
Bradycardia, hypotension, conduction abnormalities (AV block and cardiac arrest)
CNS
Headache, dizziness, convulsions
Gastrointestinal
Abdominal cramps, increased secretions, nausea, vomiting

21

Adverse Effects

Respiratory
Increased bronchial secretions, bronchospasms
Other
Lacrimation, sweating, salivation, miosi