Pharmacology Flashcards

1
Q

What are the functions of prostaglandins in the stomach?

A

Reduce acid secretion
Increase mucus and bicarbonate secretion
Increase mucosal blood flow

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2
Q

Why do NSAID’s cause peptic ulcers?

A

They reduce prostaglandin formation (COX1 inhibition)

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3
Q

What can prevent gastric damage due to long term NSAI use?

A

Stable PGE1 analogue (e.g. misoprostol)

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4
Q

How do PGE1 inhibitors prevent gastric damage by NSAID’s?

A

Inhibit basal and food-stimulated gastric acid formation

Maintain or increase secretion of mucus and bicarbonate

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5
Q

What chronic infection of the gastric Antrum is associated with peptic ulcers?

A

H. pylori

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6
Q

How does H. Pylori cause peptic ulcers?

A

H. Pylori protect in mucus gel causes a persistent inflammation that weakens the mucosal barrier
When the barrier breaks down leaves the submucosa open to attack from HCl and pepsin

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7
Q

What are the aims of treatment of peptic ulcers?

A

Reduce acid secretion
Increase mucosal resistance
Eradicate H. pylori

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8
Q

What conditions require drugs that reduce gastric acid secretion?

A

Peptic ulcer
GORD
Acid hypersecretion (e.g. Zollinger-Ellison syndrome, Cushing’s ulcers)

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9
Q

Example of PPI

A

Omeprazole

Lansoprazole

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10
Q

What is the mechanism of action of PPI’s

A

Inhibit active proton pumps

Not pumps in tubulovesicles

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11
Q

Why is the timing of PPI dosing important?

A

Must present in plasma whilst proton pumps are active

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12
Q

Side effects of PPI’s

A
Headache 
Diarrhoea/constipation 
Abdominal pain 
Flatulence 
Nausea 
Rash
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13
Q

Examples of Histamine (H2) receptor antagonists

A

Ranitidine

Cimetidine

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14
Q

What is the mechanism of action of H2 receptor antagonists?

A

Completely block histamine-mediated component of acid secretion and reduce secretion evoked by gastrin and ACh

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15
Q

Side effects of H2 receptor antagonists

A
Diarrhoea 
Headache 
Dizziness 
Rash 
Tiredness
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16
Q

Example of muscarinic ACh receptor antagonists

A

Pirezepine

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17
Q

Example of mucosal strengtheners

A

Sucralfate

Bismuth chealate

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18
Q

What is the mechanism of action of mucosal strengtheners?

A

Bind to ulcer base (+ve charged) and forms complex gels with mucus - provides mucosal barrier against HCL and pepsin

Also increases mucosal blood flow, mucus, bicarbonate and prostaglandin production

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19
Q

What class of drugs can cause peptic ulcers?

A

NSAID’s

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20
Q

What are purgatives?

A

Agents that cause purging or cleansing of the bowels by promoting evacuation

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21
Q

When should neither laxatives or purgatives be used?

A

Physical obstruction to the bowel

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22
Q

What to laxatives do?

A

Increase perostalsis and soften faeces assisting evacuation

23
Q

When are laxatives to be used?

A

If ‘straining is potentially damaging to health (angina)
Defaecation is painful (e.g. Haemorrhoids)
To clear the bowel before a procedure
To treat drug induced, bedridden, age-related constipation

24
Q

Which laxatives are faster acting, bulk or osmotic?

A

Osmotic

25
Q

Example of bulk laxative

A

Methylcellulose

26
Q

Example of osmotic laxative

A
Magnesium sulphate or hydroxide (orally) 
Sodium citrate (rectally)
27
Q

Examples of stimulant purgatives

A

Bisacodyl

28
Q

Example of faecal softener

A
Doc usage sodium (orally) 
Arachis oil (enema)
29
Q

What combination of drugs is used to control IBS?

A

Adjustment of diet
Anti-diarrhoeals
Laxatives

30
Q

What drugs are used for acute attacks of IBD?

A

Glucocorticoids

31
Q

What drugs are used in treatment of mild UC?

A

Aminosalycylates

32
Q

Examples of aminosalycylates?

A

Methalazkne
Sulfazalazine
Olsalazine

33
Q

What types of drugs have anti-motility effects?

A

Opiates

34
Q

What is the mechanism action of opiates in the GI tract?

A
Inhibit enteric neurones 
Decreased perostalsis 
Increased segmentation 
Increased fluid absorption 
Constriction of pyloric, ileocaecal and anal sphincters 
Increased tone of large intestine
35
Q

What are the major opiates that are used in diarrhoea?

A

Codeine
Diphenoxylate
Loperamide

36
Q

Mechanism of action of 5-ASA

A

Topical effect
Anti-inflammatory properties
Reduces risk of colon cancer

37
Q

Side effects of 5-ASAs

A

Diarrhoea

Idiosyncratic nephritis

38
Q

Side effects of steroids

A
A vascular necrosis 
Osteoporosis 
Acne 
Thinning of skin weight gain
Diabetes 
Hypertension 
Cataracts 
Growth failure
39
Q

Examples of immunosuppressive agents used in UC and Crohn’s

A

Adagio prime
Mercaptopurine
Methotreaxate

40
Q

Side effects of Azothioprine

A

Pancreatitis
Leukopenia
Hepatitis
Small risk of lymphoma, skin cancer

41
Q

Example of anti-TNF therapy

A

Infliximab

Adalumimab

42
Q

What is it important to exclude before prescribing anti-TNF therapy?

A

Exclude current infection/ TB

43
Q

Is surgery for Crohn’s curative?

A

No

44
Q

Is surgery for UC curative?

A

Yes can be

45
Q

What is the most common pathology of the biliary tract?

A

Cholelothiasis (gallstones)

46
Q

What is the usual treatment for gall stone?

A

Surgery

47
Q

What drug can be useful in the treatment of gallstones?

A

Ursodeoxycholic acid

48
Q

Pain relief used in the treatment of bi,airy tract disease

A

Morphine but constricts sphincter of oddi

Buprenorphine & pethidine are alternatives

49
Q

What drugs are used to relieve biliary spasm?

A

Atropine

GTN

50
Q

What is the main organ of drug metabolism?

A

Liver

51
Q

What is the first phase of drug metabolism?

A

Oxidation
Reduction
Hydrolysis

52
Q

What is phase 2 of drug metabolism?

A

Conjugation

53
Q

What mediates the oxidation reaction of the drug metabolism?

A

Haem proteins