Brainscape's Knowledge GenomeTM

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


See full index

Pharmacology and Therapeutics > Gastrointestinal Pharmacology - Motility > Flashcards

Gastrointestinal Pharmacology - Motility Flashcards

1
Q

Learning Outcomes:
• List the common therapeutic drug classes used to alter bowel motility (increase and decrease) including opioids, and the names of specific drugs within each class.
• State the mechanism of action of the commonly used therapeutic classes for altering bowel motility.
• Recognise common clinical situations where altering bowel motility is required.

A

Understood.

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

Define pro-kinetic

A

A pro-kinetic agent is a type of drug which enhances gastrointestinal motility by increasing the frequency or strength of contractions, but without disrupting their rhythm.

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

Define anti-emetic.

A

A drug that prevents vomiting.

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

Define anti-spasmodic.

A

A drug used to relieve spasm of involuntary muscle.

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

Opioids

A

Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for acute pain relief, including anesthesia.

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

What are the main anti-emetics used?

A 
Ondansetron
Cyclizine
Buscopan
Mebeverine
Metoclopramide
Domperidone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the main prokinetics used?

A 
Metoclopramide
Cyclizine
Domperidone
Prucalopride
Linaclotide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain the area of the brain involved in control of vomiting and the receptors involved.

A

Medulla oblongata

- receptors involved: Histamine, serotonin (5-HT3), muscarinic and dopamine receptors.

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

Ondansetron
Use:
Side effects:
Class:

A

Ondansetron
Use: Ondansetron is prescribed to prevent nausea and vomiting in response to cancer treatment and following surgery.
Side effects: Constipation, feeling hot, headaches. Arrhythmia’s.
Class: Anti-emetic serotonin antagonist.

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

What is the action of ondansetron?

A

Highly selective 5 HT3 (serotonin) receptor antagonist.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Metoclopramide
Use:
Side effects:
Class:

A

Metoclopramide
Use: Used for nausea and vomiting in palliative care.
Side effects: Asthenia; depression; diarrhoea; drowsiness; hypotension; menstrual cycle irregularities; movement disorders; parkinsonism.
Class: Dopamine Antagonist Anti-emetic.

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

How does metoclopramide work?

A

Blocks the dopamine mediated relaxation effect on
gastrointestinal smooth muscle.
– Increased response of the gastrointestinal smooth muscle to cholinergic stimulation.
– Increases rate of gastric emptying.
– May also strengthen the lower oesophagus sphincter,
thereby preventing acid reflux.
– Antagonizes D2 dopamine receptors in chemoreceptive.
trigger zone (CTZ) of the medulla, thereby preventing
nausea and vomiting.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why are you advised to not use dopamine antagonistic drugs for the long term?

A

They can cause permanent dyskinesia.

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

Domperidone
Use:
Side effects:
Class:

A

Domperidone
Use: Anti-emetic - commonly prescribed in IBS - improves symptoms of nausea, vomiting, bloating, and feeling of fullness.
Side effects: Dry mouth, galactorrhoea, gynecomastia, menstrual irregularities, cardiac arrhythmia’s.
Class: D2 Dopamine receptor antagonist - anti-emetic.

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

How does domperidone work?

A

Antiemetic properties are related to its dopamine

receptor blocking activity at both the chemoreceptor trigger zone and at the gastric level.

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

What are the contra-indications where you would avoid using domperidone?

A

Cardiac disease

GI obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Cyclizine
Use:
Side effects:
Class:

A

Cyclizine
Use: Travel sickness, nausea, dyspepsia, vomiting, vertigo.
Side effects: Depression, drowsiness, tachycardia, hypotension, constipation.
Class: Histamine 5HT1 Antagonist + Anti-muscarinic.

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

How does cyclizine work?

A

Cyclizine works by blocking histamine and muscarinic receptors in the vomiting centre, which prevents the vomiting centre from receiving nerve messages from the vestibular apparatus. This prevents disturbances in the middle ear from activating the vomiting centre and causing nausea, vertigo and vomiting.

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

What are the contraindications where you would avoid prescribing this drug?

A 
– Cardiac disease
– Liver disease
– Acute angle glaucoma
– GI obstruction
– Myasthenia gravis
– Active colitis
– Urinary retention
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Buscopan
Use:
Side effects:
Class:

A

Buscopan
Use: It relieves the pain of stomach and bowel cramps by helping your digestive system to relax.
Side effects: Tachycardia, Hypotension, Anaphylaxis.
Class: Anti-spasmodic. Anti-muscarinic (anti-cholinergic).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does buscopan work?

A

• Peripherally acting anticholinergic agent
• Binds to muscarinic M3 receptors located on
postganglionic parasympathetic nerve endings
on smooth muscle cells.
• Blocks the activity of acetylcholine
• Inhibits smooth muscle contraction
• Antispasmodic effect in the gastrointestinal,
urinary, uterine, and biliary tracts

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

What are the contra-indications where buscopan should not be used?

A 
– Cardiac disease.
– Acute angle glaucoma
– GI obstruction
– Myasthenia gravis
– Active colitis
– Urinary retention
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the four different classes of laxative?

A

Bulk forming
Osmotic
Stimulating
Softeners

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Linaclotide
Use:
Side effects:
Class:

A

Linaclotide
Use: For relieving symptoms of irritable bowel syndrome (IBS) with constipation and for treating chronic constipation of unknown cause (idiopathic constipation).
Side effects: Diarrhoea; dizziness; gastrointestinal discomfort; gastrointestinal disorders.
Class: Secretagogue and analgesic with laxative activity.

25
Q

Why does buscopan and cyclizine have side effects of tachycardia and hypotension which is why they should not be prescribed in someone with cardiac disease?

A

They are both anti-cholinergics.

26
Q

How does Linaclotide work?

A

Binds to GC-C receptors located on the luminal surface of the intestinal epithelium.
– Via cGMP activates the cystic fibrosis transmembrane conductance regulator (CFTR) and stimulates the secretion of chloride and bicarbonate into the intestinal lumen.
• This promotes sodium excretion into the lumen and results in increased intestinal fluid secretion. This ultimately accelerates GI transit of intestinal contents, improves bowel movement and relieves constipation.

27
Q

What are the contra-indications where you would avoid using linaclotide?

A

Gastro-intestinal obstruction

Inflammatory bowel disease

28
Q

Prucalopride
Use:
Side effects:
Class:

A

Prucalopride
Use: Chronic constipation
Side effects: Appetite decreased; diarrhoea; dizziness; fatigue; gastrointestinal discomfort; gastrointestinal disorders; headache; nausea; vomiting.
Class: Serotonin 5-HT4 Receptor Agonist

29
Q

How does prucalopride work?

A

5-HT 4 receptors are distributed throughout
the gastrointestinal tract and stimulation of
these receptors enhances intestinal secretion,
augments the peristaltic reflex, and increases
gastrointestinal transit.

30
Q

What are the contra-indications where you would avoid using prucalopride?

A

– Reduce dose in renal impairment.
– IBD.
– GI obstruction.
– Cardiac disease (previous 5-HT4 agonists withdrawn due to cardiac events).

31
Q

Opioids bind to what opioid receptors?

A

Mu
Delta
Kappa

32
Q

What are the functions / effects of an opioid that binds to a mu receptor?

A 
Slowed GI transit
Physical dependence
Euphoria
Supraspinal and spinal anaesthesia
Modulation of hormone, neurotransmitter release.
Inhibition of respiration
33
Q

What are the functions / effects of an opioid that binds to a delta receptor?

A

Supraspinal and spinal anaesthesia

Modulation of hormone, neurotransmitter release.

34
Q

What are the functions / effects of an opioid that binds to a kappa receptor?

A

Supraspinal and spinal anaesthesia
Slowed GI transit
Psychotomimetic effects

35
Q

How can opioids cause bowel dysfunction?

A

Decreased gastric emptying and increased pyloric tone.
– anorexia, nausea and vomiting
• Inhibition of propulsion and increased fluid absorption from the small and large intestine
– delayed absorption of medications
– hard dry stools and constipation
• Increased anal sphincter tone and impaired reflex relaxation in response to rectal distention.
– impaired ability to evacuate the bowel
• Increased amplitude of non-propulsive segmental contractions.
– abdominal spasm, cramps, pain, distension and bloating.
• Decreased gastric, biliary, pancreatic and intestinal secretions interfere with digestion.

36
Q

Loperamide
Use:
Side effects:
Class:

A

Loperamide
Use: Treats sudden diarrhoea and travellers diarrhoea.
Side effects: Headache nausea.
Class: Opioid agonist that acts on the µ-receptors in the intestinal mucosa.

37
Q

How does loperamide work?

A

• Acts on the µ-receptors in the intestinal mucosa.
• Decreases gastrointestinal motility by decreasing the circular and longitudinal smooth muscle activity.
• Slows intestinal transit.
• Increases water and electrolyte absorption from the intestines.
• Loperamide is not significantly absorbed from the gut and does not cross the blood-brain barrier
– no central nervous system effects e.g euphoria.

38
Q

Eluxadoline
Use:
Side effects:
Class:

A 
Eluxadoline
Use: Treats IBS with diarrhoea.
Side effects: Pancreatitis
Class: Mixed opioid:
– μ- and κ-opioid receptor agonist
– δ-opioid receptor antagonist
39
Q

What are the contra-indications where you would avoid using eluxadoline and why?

A

There is a risk of pancreatitis so do not use in patients who have undergone cholecystectomy or in those with biliary disorders.

40
Q

Methylnaltrexone
Use:
Class:

A

Methylnaltrexone
Use: Methylnaltrexone blocks the constipating effects of opioids without altering their central analgesic effect.
Class: Peripherally acting µ-opioid receptor antagonist.

41
Q

Do not use anti-cholinergics in patients with what condition?

A

Cardiac disease

42
Q

Loperamide aka

A

Immodium

43
Q

Define:
Nausea
Emesis
Anti-emetic

A

Nausea - feeling sick
Emesis - being sick
Anti-emetic - a drug that stops you being sick.

44
Q

How does the medulla oblongata detect when you need to vomit?

A

Medulla oblongata lacks a blood brain barrier and so can detect emetic toxins in blood and csf.

45
Q

The vomiting centre is stimulated by an increase in what neurotransmitters?

A

Muscarinic
Histaminic
Serotonergic

46
Q

What are the uses of emesis?

A 
Rid the body of toxins
Reduce pressure in the stomach
     - Food/drink intake
     - GI obstruction
Stop future ingestion of toxins
47
Q

What are the complications of vomiting?

A 
Dehydration
Metabolic alkalosis
Hypokalaemia
Hypochloraemia
Pathological in eating disorders
Dental decay
Mallory weiss tear
48
Q

Mallory-weiss tear

A

A Mallory-Weiss tear is a tear of the tissue of your lower esophagus. It is most often caused by violent coughing or vomiting.

49
Q

How do anticholinergics work?

A

Antagonise muscarinic receptors.

50
Q

Where are anticholinergics used?

A

Used in palliative care and gastroenterology as an antispasmodic and antiemetic.

51
Q

What are the side effects of anticholinergics?

A

Side effects include sedation, amnesia, central

anticholinergic syndrome.

52
Q

What are the general uses of antihistamines?

A

Wide use of application

  • Motion sickness
  • Radiotherapy induced emesis
  • Post operative emesis
  • Meniere’s
  • Allergy
53
Q

What are the side effects of antihistamines?

A

Side effects; drowsiness, restlessness, excitation (IV)

54
Q

Explain the action of Cannabinoids and what they are used for?

A

Act on CB1 and CB2 receptors

Used for malignancy and chemotherapy induced emesis, also intractable epilepsy.

55
Q

What are the side effects of Cannabinoids?

A

Side effects : impaired psychomotorperformance, nausea, vomiting, hyperemesis syndrome, psychosis.

56
Q

How does chemotherapy and radiotherapy induce vomiting?

A

 Cytoxic
 Stimulates 5-HT3 release in the GI wall
 Increased 5-hydroxy-indole acetic acid (serotonin metabolite).
 Vagal afferent neurones
 Stimulate 5-HT3 in the chemoreceptor trigger zone.
 90% of total body irradiation
 Chemotherapy can induce vomiting for weeks after exposure.

57
Q

How does pregnancy induce vomiting?

A
  • Direct result of bHCG
  • 75% pregnancies
  • More common in first trimester and multiple
    gestation.
  • Simulate CTZ and induce nausea and emesis
  • At extreme end can cause hyperemesis
    gravidarum.
  • Drugs best avoided in pregnancy!
  • Antihistamines, phenothiazines
  • (Chlorpromazine/ Prochlorperazine)
  • Metoclopramide and ondansetron second
    line.
  • Corticosteroids third line
58
Q

Which anti-emetic is a serotonin antagonist?

A

Ondansetron

Pharmacology and Therapeutics (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions