Pharm Flashcards

1
Q

What are peptic ulcers?

A
  • Peptic ulcer involves breakdown of the protective mucosal layer in one particular region of
  • the stomach or upper duodenum resulting in an ulcer which may be painful as a result of irritation by acid and pepsin.
  • H. pylori and NSAID use are important risk factors for peptic ulcers
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2
Q

Describe a pathway by which HCL is secreted into the lumen of the stomach (1)

A
  • Vagus
  • →releases Ach
  • →Musc receptors on ECL cells
  • → stimulate M1 receptors
  • → release of histamine
  • →histamine binds to H2 receptor on parietal cell
  • → Parietal cell releases gastric acid (HCl)
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3
Q

Describe a pathway by which HCL is secreted into the lumen of the stomach (2)

A
  • Vagus
  • →releases Ach
  • →G cell releases gastrin
  • →gastrin acts on ECL cell OR
  • →Parietal cell
  • → Parietal cell releases gastric acid (HCl)
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4
Q

Describe a pathway by which HCL is secreted into the lumen of the stomach (3)

A
  • Vagus
  • →releases Ach
  • →stimulates parietal cell directly
  • →parietal cell releases gastric acid (HCl)
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5
Q

What is a PPI?

How does it work?

A

H+/K+ ATPase inhibitors/Proton Pump Inhibitors
It irreversibly destroys the proton pump
Therefore it decreases gastric acid secretion

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6
Q

What are the PPIs you need to know?

A
  • Omeprazole (1st PPI ever)
  • Esmomeprazole (most important one – v v v popular)
  • ‘OLE’
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7
Q

What is a Histamine H2 antagonist?

How does it work?

A

Inhibits histamine from binding to H2 receptor on parietal cell
thus parietal cell cannot releas gastric acid (HCl)

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8
Q

What Histamine H2 antagonist do you need to know?

A

Ranitidine (Zantac – main one used)

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9
Q

What is better H2 antagonist or PPI?

A

PPIs

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10
Q

What is the treatment for H. pylori?

A

Must eradicate H pylori to make ulcer doesn’t return. Therefore use PPI & amoxicillin & clarithromycin

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11
Q

How do antacids work?

A

• neutralize gastric acid

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12
Q

What are the side effects of the components of antacids?

A
  • Mg → diarrhea
  • Al → constipation
  • Ca →constipation/ hypercalcaemia
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13
Q

Why are antacids used, what are the drawbacks of its use?

A
  • Symptomatic relief
  • Some are short acting, some are long acting.
  • Combine all these salts (Mg, Al, Ca) to ↓ SEs.
  • When you stop taking them, they stimulate rebound hyperacidity.
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14
Q

How do muscurinic receptor antagonists work?

A

i. Muscarinic receptor antagonist block ACh (normally increases motility)

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15
Q

What is an muscurinic antagonist spasmolytic?

A

• hyoscine butylbromide (Buscopan)

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16
Q

What are the direct spasmolytics and how do they act?

A

Direct spasmolytic (act directly on SM to relax it) = mebeverine, peppermint oil

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17
Q

How do PGE analogues work?

A
  • ↑ mucous secretion
  • ↑ mucosal blood flow (removes XS H+)
  • ↓ gastric acid secretion
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18
Q

When are PGE contraindicated?

A
  • Severe diarrhoea

* ↑ uterine contractions (don’t use in pregnant women)

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19
Q

What is the name of a PGE analogue?

A

• Misoprostol

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20
Q

What is the Chemoreceptor trigger zone (CTZ)

A

The CTZ is located in the medulla outside the blood brain barrier. It communicates with other structures in the vomiting centre to initiate vomiting.

As a result of its position outside of the BBB it is sensative to toxins, bacteria, drugs

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21
Q

Name a H1 receptor antagonist?

A

Promethazine

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22
Q

Where does promethazine act?

A

In the gut - it does not enter the CNS

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23
Q

What is a side effect of H1 receptor antagonists?

A

Sedative

24
Q

Name a muscurinic receptor antagonist?

A

Hyoscine hydrobromide

25
Q

What are some features of hyoscine hydrobromide

A

It is absorbed and enters into the CNS

26
Q

What are some side effects of muscurinic receptor antagonists?

A

Sedative

Anti-SLUD

27
Q

What are the 2 classes of drugs which act against motion sickness?

A

Histamine H1 receptor antagonists

Muscarinic receptor antagonis

28
Q

What are the drugs that act on CTZ stimulated emesis?

A

Dopamine D2 receptor antagonists

5HT3 receptor antagonist

29
Q

What are some side effects of D2 receptor antagonists?

A
  • Sedation
  • prolonged blockade of D2s (difficulty moving (parkinson’s like symptoms)
  • Extrapyramidal SEs (tardive dyskinethesia)
  • Late onset, irreversible
30
Q

What are some D2 RAs?

A
  1. Metoclopramide (maxillon)
  2. Prochlorperazine (Stematil)
  3. Domperidone (doesn’t cross BBB)
31
Q

What is a 5HT3 receptor antagonist?

A

ondansteron

32
Q

When is ondansteron used?

A
  • Used to prevent extreme nausea caused by anaesthetics and chemotherapy
  • V effective
33
Q

Side effects of ondansteron?

A

Minor GI upset

Can cause constipation and headaches

34
Q

What are some features of Metoclopramide?

A

Also has 5HT3 antag properties in higher doses.
• Can also act as agonist on 5HT4 receptors (acts in the gut here)
• Also facilitates gastric emptying by releasing [Ach] from 5HT4 receptors s absorption of drugs (v important for ppl with migraines who have a lot of nausea.
• Doesn’t cause gastric emptying in colon (ie TF doesn’t cause diarrhoea.
• Used in gastroparesis (delayed gastric emptying) occurs in nerve damage or diabetes.

35
Q

What do saline laxatives do?

A

Saline Laxatives – these are slowly absorbed ions which cause osmotic fluid retention → colonic stimulation by distension due to increased fluid volume

36
Q

Name a saline laxative

A

Magnesium sulphate (Epsom salts®), Sodium phosphate, Sodium citrate

37
Q

What are bulking agents?

A

Hydrophobic colloids; indigestible fibre -> greater faecal water retention -> greater volume of intestinal contents -> increased normal reflex bowel activity

38
Q

Name some bulking agents?

A

Bran, psyllium, isphaghula husk, sterculia

39
Q

What are Faecal softeners and lubricants?

A

Detergents; enhance mixture of water in faeces

40
Q

Name 2 Faecal softeners and lubricants ?

A

Docusate, poloxamer

41
Q

Name a lubricant mineral oil?

A

Liquid paraffin

42
Q

How do disaccharide (galacto-fructose) hydrophilic colloid laxative?

A

Differs from bulk laxatives in that it increases the bulk of colonic contents by osmosis

43
Q

Name a Disaccharide (galacto-fructose) Hydrophilic Colloi

A

Lactulose

44
Q

How do polyols work?

A

often added to confectionery as an artificial sweetener – similar action to lactulose

45
Q

Name a polyol

A

Sorbitol

46
Q

How do Macrogols or Polyethylene Glycols (PEGs) work?

A

Inert polymers of large molecular weight – electrolytes are usually added to maintain balance

47
Q

What are PEGs?

A

Bowel preparations

48
Q

What are other osmotic laxatives?

A

Other – may also have lubricating and mild stimulant properties – usually in suppository form 1. Glycerol

49
Q

What are stimulant laxatives?

A

unknown mode of action; may stimulate colonic myenteric plexuses, irritate intestinal mucosa or by direct sensory nerve ending increase motility; may also reduce net reabsorption of water and electrolytes

50
Q

What are some stimulant laxatives?

A

Bisacodyl, sodium picosulphate, senna, frangula

51
Q

What are Antidiarrhoeal drugs?

A

Opioids
Musculotropic antispasmodic
Muscarinic Receptor Antagonists

52
Q

How do opiods work as antidiarrhoeal drugs?

A

Most commonly used (cause constipation); stop ACh release and slow down movement of the bowel

53
Q

Name an opid antidiarrhoeal drug?

A

Loperamide (immodium)

54
Q

Name a Musculotropic antispasmodic drug?

A

Mebeverine

55
Q

Name a Muscarinic Receptor Antagonistsantispasmodic drug?

A

Hyoscine butylbromide

56
Q

How do anti-flatulence agents work?

A

Agents used for treatment of flatulence = defoaming agent which results in coalescence of gas bubbles (1 big air bubble now passes more effectively).

57
Q

What is an Anti-flatulence agent?

A

Simethicone