Brainscape's Knowledge GenomeTM

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


See full index

SGUL - Physiology 1 > Pharmacological Basis - Treatment of GI Disorders > Flashcards

Pharmacological Basis - Treatment of GI Disorders Flashcards

1
Q

List some areas of GIT importance.

A
  • gastric acid secretion
  • gut motility
  • bile formation and excretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are two types of anti-secretory agents?

A

H2 receptor antagonists and proton pump inhibitors.

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

What are the clinical uses of H2 receptor antagonists?

A
  • Inhibit histamine-, ACh- and gastrin-stimulated acid secretion on parietal cells.
  • Reduce gastric acid secretion ∴ reduce pepsin secretion.
  • Promote the healing of duodenal ulcers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List some examples of H2 receptor antagonists.

A
  • Ranitidine
  • Cimetidine
  • Famotidine
  • Nizartidine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some side effects of H2 receptor antagonists?

A
  • diarrhoea
  • muscle cramps
  • transient rashes
  • hypergastrinaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some side effects specific to cimetidine?

A
  • Gynaecomastia
  • Inhibition of P450 enzyme ∴ reduced metabolism of drugs broken down by these enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do proton pump inhibitors work?

A
  • Weak bases - inactive at a neutral pH.
  • Irreversibly inhibit the H+/K+-ATPase pump ∴ less H+ in the cell to make HCl.
  • Decreases basal and food-stimulated gastric acid secretion.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

List examples of proton pump inhibitors.

A
  • Omeprazole
  • Lanzoprazole
  • Pantoprazole
  • Rabeprazole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the clinical uses of proton pump inhibitors?

A
  • peptic ulcers
  • reflux oesophagitis
  • against H. Pylori
  • against Zollinger-Ellison syndrome (overproduction of gastric acid)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are some side effects of proton pump inhibitors?

A
  • headaches
  • diarrhoea
  • mental confusion
  • rashes
  • somnolence (strong desire to sleep)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Prostaglandins are gastroprotective.
How do they work?

A
  • Increase mucous secretion
  • Stimulate bicarbonate secretion
  • Promotes vasodilation
  • Negatively regulates parietal cells, so reduces H+ secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why do NSAIDs (eg. aspirin) cause gastric bleeding?

A
  • Cause gastric bleeding
  • Inhibit prostaglandin synthesis (meaning there is less gastric protection)
  • Inhibit Thromboxane A2 synthesis (which is involved in healing).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What would be a good alternative for NSAIDS to reduce bleeding?

A

Selective COX-2 inhibitors (such as celecoxib, rofecoxib)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What effect does dopamine have on the gut?

A
  • Relaxant effect on the gut by activating D2 receptors in the lower oesophageal sphincter and stomach (fundus and antrum).
  • Inhibits ACh release.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What would you need to do with dopamine if you wanted to increase gut motility?

A

Reduce or stop its effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

By which three mechanisms does metoclopramide promote gut motility?

A
  • Inhibition of pre- and post-synaptic D2 receptors
  • Stimulation of presynaptic, excitatory 5-HT4 receptors
  • Antagonism of presynaptic inhibition of muscarinic receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does metoclopramide promote the release of?

A

It promotes the release of ACh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the effects of metoclopramide?

A
  • increases LOS tone and gastric tone
  • increases intragastric pressure
  • improved antroduodenal coordination and accelerated gastric emptying
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe how antispasmodic agents work

A
  • Decrease spasms in the bowel.
  • Relax the smooth muscle in the GIT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Give examples of antispasmodic agents.

A
  • propantheline (antimuscarinic agent)
  • dicloxerine (dicyclomine)
  • mebeverine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When might an antispasmodic agent be useful clinically?

A

Irritable bowel syndrome and diverticular disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the goals of pharmacological intervention in gastric ulcers?

A
  • reduce acid secretion with H2 receptor antagonists
  • neutralise secreted acid with antacids
  • attempt to eradicate H.pylori
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the general mechanism of antacids?

A
  • Neutralise gastric acid
  • Increase the pH of gastric acid
  • Prolonged dosing can lead to healing of duodenal ulcers (less effective for gastric ulcers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some examples of antacids?

A
  • sodium bicarbonate
  • calcium carbonate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How does bismuth chelate work?

A

It protects the gastric mucosa:
- forms a base over the crater of the ulcer
- adsorbs pepsin
- increased HCO3- and PG secretion
- toxic against H.pylori, and used as part of a triple therapy to eradicate it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the side effect of bismuth chelate?

A

Blackens the stool and tongue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How would you treat an H.pylori infection?

A
  • Use a combination therapy of at least three drugs (proton pump inhibitor and antibiotics):
  • Advise patient to adhere to the treatment and watch out for resistance to metronidazole (you can’t take it with alcohol)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are some possible drug combinations for H. pylori infections?

A

omeprazole, amoxicillin, and metronidazole
[omeprazole, clarythromycin, and amoxicillin] or [tetracycline, metronidazole, and bismuth chelates]

29
Q

What are some consequences of constipation as a result of rectal distention?

A
  • headache
  • nausea
  • abdominal distention and stomach pain
30
Q

What are some causes of constipation?

A
  • decreased motility of the large intestine
  • old age
  • damage to the enteric system of the colon
31
Q

List some factors that can improve colonic motility.

A
  • increased fibre, cellulose and complex polysaccharides
  • laxatives
  • mineral oil, as it lubricates the faeces
  • castor oil, as it stimulates the motility of the colon
32
Q

What are some alarm signs and symptoms of someone with chronic constipation?

A
  • acute onset of constipation in older individuals
  • weight loss (10 lbs)
  • blood in the stool
  • anaemia
  • family history of colon cancer
33
Q

How would you manage constipation?

A
  • change the diet, fluid intake and exercise
  • increased fibre intake
34
Q

Describe bulk-forming/osmotic laxatives and how they work.

A
  • Retain water in the gut lumen, thus promoting peristalsis
  • Take a few days to work.
35
Q

Give an example of a bulk-forming/osmotic laxative

A

Methylcellulose

36
Q

What are the side effects of bulk-forming/osmotic laxatives?

A

Bloating

37
Q

How do antidiarrhoeal agents work?

A

Maintain body fluids and electrolytes by modifying secretion and absorption balance

38
Q

What is loperamide?

A
  • Synthetic opioid receptor agonist.
  • Spasmolytic agent which reduces smooth muscle activity in the GIT, and thus, reduces the passage of faeces.
39
Q

What does loperamide do?

A
  • Reduces the force and speed and colonic movement
  • Increases haustral mixing of the proximal colon
  • Inhibits propulsive mass movement of the distal colon
40
Q

How is the H+/K+ pump activated by action of gastrin?

A
  • Gastrin can activate cells to release histamine
  • Binds to H2 receptors on parietal cells
  • Activates the H+/K+ ATPase pump
41
Q

What does IC50 mean?

What does it mean if a drug were to have a low IC50?

A

→ Inhibitory concentration
→ Drug is more powerful

42
Q

What protects the gastric mucosa?

A

→ PGE1
→ PGE2

43
Q

What drugs protect the gastric mucosa?

A

Misoprostol

44
Q

What does misoprostol inhibit?

A
  • Inhibits basal and food stimulates gastric acid secretion
  • Inhibits histamine and caffeine-induced gastric secretion
  • Inhibits the activity of parietal cells
45
Q

What does misoprostol increase and induce?

A
  • Increases mucosal blood flow and can augment the secretion of HCO3- and mucus
  • Induces labour
46
Q

What do 5HT3 receptors do?

A

Receptors which inhibits vomiting

47
Q

What does dopamine do in the distal and proximal areas of the gut?

A

Induce contraction in the proximal and relaxation in the distal

48
Q

What two properties does metoclopramide have?

A

Antiemetic properties and relieves headache via central effects

49
Q

What is metoclopramide useful for?

A

→ GI reflux

50
Q

What does metoclopramide stimulate and accelerate?

A

→ Stimulates: gastric motility
→ Accelerates: gastric emptying

51
Q

What neurons does metoclopramide stimulate?

A

→inhibitory nitregic neurons
→mediate NO release

52
Q

What are the effects of metoclopramide? PART 1

A

→Inhibits presynaptic and postsynaptic D2 receptors
→Stimulates the release of ACh from enteric neurons
→Elicits mixed 5-HT agonist and antagonist effects, e.g., stimulates excitatory 5-HT4 receptors (ENS), but inhibits 5-HT3 receptors (CNS);

53
Q

What are the effects of metoclopramide? PART 2

A

→Stimulates inhibitory nitregic neurons – mediate NO release
→Increases intragastric pressure -↑ LOS and gastric tones
→Motility stimulant - improves antro-duodenal coordination and accelerated gastric emptying

54
Q

What do muscarinic receptor antagonists do?

A

→inhibit parasympathetic activity which reduces spasm in the bowel

55
Q

What type of bacteria is H.Pylori?

A

Gram negative bacillus

56
Q

What can bismuth chelate cause?

A

Encephalopathy

57
Q

What is H.Pylori a risk factor for?

A

Gastric cancer

58
Q

What cytoprotective effects does bismuth chelate have?

A

→Provide a physical barrier over the surface of the ulcer
→Enhances local synthesis of prostaglandins
→Promote bicarbonate secretion

59
Q

What reaction happens if metronidazole is taken with alcohol?

A

→Disulfiram like reaction

60
Q

What does disulfiram do to alcohol?

A

→ Inhibits acetaldehyde dehydrogenase so acetaldehyde builds up

61
Q

What can purgatives do?

A

Modulate food transit in the intestine

62
Q

What do osmotic laxatives do?

A

→Increases and maintains the volume of fluid in the lumen of the bowel by osmosis

63
Q

What do high doses of osmotic laxatives cause?

A

→ cramps
→diarrhoea
→ vomiting

64
Q

What are 4 causes of diarrhoea?

A

→Infectious agents
→Toxins
→Anxiety
→Drugs

65
Q

What does oral rehydration therapy do?

A

→maintain fluid and electrolyte balance

66
Q

What does bismuth subsalicylate do?

A

→Decreases fluid secretion in bowel
→Safe for young children
→Tinnitus and blackening of stool

67
Q

Where does loperamide exert its effects?

A

→Exerts effects on opioid receptor of the myenteric plexus of the large intestine

68
Q

Why does loperamide not have CNS effects?

A

→ Does not cross the blood-brain barrier

SGUL - Physiology 1 (68 decks)

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