Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology Exam 1 > 14 - GI Pharmacology II > Flashcards

14 - GI Pharmacology II Flashcards

1
Q

What are the common neurotransmitters that affect gastric motility?

A
  • Serotonin (inc.)
  • Dopamine (dec.)
  • Acetylcholine (inc.)
  • Motilin (inc.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does serotonin induce gastric motility?

A

By inducing the

release of acetylcholine by neurons onto gastrointestinal smooth muscle (contraction of gastric smooth muscle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does dopamine affect gastric motility?

A

By activating presynaptic receptors to decrease the firing of ENS neurons, therefore decreasing gastric motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does acetylcholine affect gastric motility?

A

By activating muscarinic receptors to induce contraction of gastrointestinal smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does motilin affect gastric motility?

A

Promotes gastric motility through activation of motilin receptors located on gastrointestinal smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the four prokinetic agents used to increase gastric motility?

A

1 - Metoclopramide
2 - Bethanechol
3 - Neostigmine
4 - Erythromycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the mechanism of action and use of metoclopramide?

A
  • D2 antagonist (blocks the dopamine receptor - remember dopamine slows down gastric motility)
  • Used to treat GERD, impaired gastric emptying, dyspepsia and is used as an antiemetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the adverse effects of metoclopramide?

A
  • CNS (restlessness, drowsiness, insomnia, anxiety)

- Altered motor function (Parkinsonian symptoms - because it can cross the BBB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the mechanism of action and use of bethanechol?

A
  • M3 anonist (stimulates ACh receptor

- Used to treat GERD and gastroparesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the adverse effects of bethanechol?

A
  • Cholinergic side effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the mechinism of action and use of neostigmine?

A
  • AChE inhibitor

- Used to treat non-obstructive urinary retention and abdominal distention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the adverse effects of neostigmine?

A
  • Cholinergic side effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the mechanism of action and use of erythromycin?

A
  • Motilin receptor agonist (increases the effects of motilin)
  • Used to treat gastroparesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the adverse effects of erythromycin?

A
  • Erythromycin mediated side effects

- Antibiotic use can cause diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are laxatives commonly used to treat?

A
  • Constipation (infrequent evacuation of the feces)
  • Minimizing strain during defecation following cardiothoracic surgery
  • Clear GI tract before endoscopy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the main causes of constipation?

A
  • Hormone secreting tumors that decrease motility
  • Presence of toxins
  • Various disease states
  • Diet, stress, exercise, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

There are 8 laxatives you need to know about, which can be grouped into either physical-induced laxatives (4) and receptor-induced laxatives (4)

A

Physical-induced laxatives

  • Methylcellulose (bulk-forming)
  • Glycerin (surfactant)
  • Lactulose (osmotic)
  • Senna (stimulant)

Receptor-induced laxatives

  • Tegaserod (serotonin agonist)
  • Lubiprostone (chloride channel activator)
  • Methylnaltrexone (mu-opioid receptor antagonist)
  • Alvimopan (mu-opioid receptor antagonist)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

For the physical-induced laxatives, how good is the absorption?

A

Poor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

For the physical-induced laxatives, what is the use?

A
  • Constipation
  • Minimize straining
  • Prior to surgical or endoscopic procedure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does the bulk-forming methylcellulose work?

A
  • Non-digestible fiber forms a gel-like substnace in the intestine and causes distention of the GI tract which induces peristalsis

Their adverse effect is gas and bloating

21
Q

How do surfactant stool softeners like glycerin work?

A

The stool is penetrated by water and lipids which lubricates the hardened stool and coats it for easy passage

Their adverse effect is nutrient malabsorption

22
Q

How do osmotic laxatives like lactulose work?

A

Induce a change in osmotic pressure inducing water absorption back into the lumen of the colon

Their adverse effect is gas and electrolyte flux

23
Q

How do stimulant laxatives like senna work?

A

They stimulate the ENS to induce peristaltic contractions

Their adverse effect is GI irritation

24
Q

Describe the serotonin agonist tegaserod

A
  • A 5-HT4 partial agonist
  • Poor absorption (10%)
  • Used to treat chonic idiopathic constipation
  • NOT available for general use (GI and cardiovascular adverse effects)
25
Q

Describe the chloride channel activator lubiprostone

A
  • It is a prostaglandin derivative
  • Poor absorption
  • Used for chronic constipation
  • Stimulates chloride ion secretion and thus fluid secretion by the large intestine
  • Adverse effects of nausea/vomiting and diarrhea
26
Q

Describe the mu-opioid receptor antagonists (methylnaltrexone and alvimopan)

A

Block peripheral mu-opiod receptors

**Peripheral is the key here”*

These agents do not cross the BBB, so they are able to block the constipating effects of opioids without blocking the intended therapeutic effect in the CNS

27
Q

What is methylnaltrexone mainly used for?

A

To alleviate opiod-induced constipation during palliative care

The adverse effects are abdominal pain, gas, nausea and diarrhea

28
Q

What is alvimopan mainly used for?

A

Postoperative ileus (obstruction) in hospitalized patients with bowel resection

Adverse effects are similar to methylnaltrexone but include MI, so it can only be used for SHORT TERM use (7 days)

29
Q

What are the 5 drugs you need to know which have an anti-diarrheal effect?

A 
1 - Loperamide
2 - Diphenoxylate
3 - Bismuth subsalicylate
4 - Cholestyramine
5 - Octreotide
30
Q

Which two anti-diarrheal agents are opioid agonists?

A

Loperamide and diphenoxylate

31
Q

What is loperamide used to treat?

A

AKA Imodium

Diarrhea from IBS

The only adverse effect is constipation (it is otherwise very safe)

32
Q

What is diphenoxylate used to treat?

A

AKA lomotil

Diarrhea

Adverse effects are CNS and atropine effects

33
Q

How does bismuth subsalicylate work?

A

AKA pepto bismal

Antidiarrheal effects occur through inhibition of prostaglandin synthesis in the intestine (this contrasts what happens in the stomach)

Also, through the ability of bismuth subsalicylate to absorb toxins secreted by bacteria

Can develop salicylate toxicity at high doses

34
Q

What is bismuth subsalicylate particularly helpful in treating?

A

Traveler’s diarrhea

35
Q

How does cholestyramine work?

A

It is a bile salt resin which are used to treat diarrhea caused by malabsorption of bile salts by the ileum in cases of Crohn’s disease or resection of the ileum

They reduce osmotic pressure which is caused by unabsorbed bile salts

Adverse effects include bloating, gas, constipation, fecal impaction and impaired fat absorption

36
Q

How does octeotride work?

A

It is a peptide that activates the somatostatin receptor in the GI tract to increase fluid absorptionand decrease motility so there is more time to absorb water

Useful in treating secretory diarrhea

Adverse effects include impaired pancreatic secretion, decreased motility, decreased gall bladder contraction, glucose homeostasis

37
Q

What is an emetic response?

A

Vomiting

38
Q

What can initiate an emetic response?

A
  • Sensory stimulation
  • Blood-borne emetics
  • Gastrointestinal irritants
39
Q

What part of the brain initiates emesis?

A

Medulla

40
Q

What receptors mediate the emetic response?

A
  • Serotonin (5-HT)
  • Dopamine (D)
  • Muscarinic (M)
  • Histamine (H)
  • Neurokinin (NK)
41
Q

Why are these receptors relevant?

A

Simply antagonizing these receptors can block or blunt an emetic response

They are all pro-emesis so if you block them, you stop vomiting

42
Q

What are the six receptor antagonists that are anti-emetics and what receptor do they block?

A 
1 - Ondansetron (5-HT)
2 - Scopolamine (M1)
3 - Metoclopramide (D2)
4 - Dimenhydrinate (H1)
5 - Aprepitant (NK1)
6 - Prochlorperazine (M1, D1, H1)
43
Q

Which of the anti-emetic receptor antagonists are used to treat motion sickness?

A
  • Scopolamine (patch behind the ear)

- Dimenhydrinate (AKA dramamine - causes drowsiness)

44
Q

Which of the anti-emetic receptor antagonists are used to treat chemo, radiation and post-op vomiting?

A
  • Ondansetron
  • Metoclopramide
  • Aprepitant
45
Q

Which is used to treat severe vomiting?

A

Prochlorperazine

It is the end all cure all… Last resort that you use when all else fails

46
Q

What other sites in the CNS would be useful targets for anti-emetic therapy?

A
  • GABAergic neurons
  • Cannabinoid receptors
  • Glucocorticoid receptors
47
Q

What are these alternative anti-emetic drugs used for?

A

Mostly for chemotherapy vomiting

48
Q

What are the three agonists for anti-emetic therapy?

A

1 - Lorazepam (GABA agonist, anxiety)
2 - Nabilone (Cannabinoid agonist)
3 - Dexamethasone (glucocorticoid agonist, post-op)

Pharmacology Exam 1 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions