GORD/Peptic Ulcer Pharmacology Flashcards

1
Q

what is the MOA for NSAIDs?

A

inhibit enzyme cyclo-oxygenase (which generates prostaglandins and thromboxanes)
exibits analgesic effects by reduced prostaglandin effects so less sensitisation to pain
also anti inflammatory via reduced prostaglandin effects

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2
Q

what is the drug target for NSAIDs?

A

cyclo-oxygenase enzyme (COX-1 &2)

COX-1 gives unwanted effects while COX-2 gives the analgesic effect

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3
Q

what are the main side effects for NSAIDs?

A

gastric irritation, ulceration, bleeding, perforation
REDUCED CREATININE CLEARANCE, nephritis,
bronchoconstriction
skin rashes,
dizziness,
tinnitus

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4
Q

What are some NSAIDs?

A

Ibruprofen
Naproxen
Diclofenac

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5
Q

what are the risks of long term NSAID use?

A

CV effects - stroke, MI, hypertension

chronic renal failure/CKD

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6
Q

what is the MOA for proton pump inhibitors?

A

irreversible inhibitor of H+/k+ATP pump in gastric parietal cells
therefore inhibits basal and stimulated gastric acid secretion by over 90%

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7
Q

What are some PPIs?

A

Omeprazole
Lansoprazole

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8
Q

what is the drug target for PPIs?

A

H+/K+ ATP pump

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9
Q

what are the main side effects of PPIs?

A

headache, diarrhoea, bloating, abdominal pain, rashes

may mask gastric cancer

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10
Q

what is the MOA for H2 receptor antagonists?

A

competitive antagonists of H2 histamine receptors
inhibit stimulatory action of histamine release from enterochromaffin-like cells on gastric parietal cells
inhibits gastric acid secretin by ~60%

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11
Q

what is the drug target for H2 receptors antagonists?

A

histamine H2 receptor on gastric parietal cells

stops histamine action after its release from enterochromaffin like cells

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12
Q

what are the main side effects of histamine H2 receptor antagonists?

A
fairly uncommon
diarrhoea, 
dizziness, 
muscle pains, 
transient rashes
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13
Q

give examples of H2 receptor antagonists?

A

cimetidine, rantidine

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14
Q

what is an additional side effect of cimetidine (an H2 receptor antagonist)?

A

inhibits cytochrome P450 may retard metabolism and effect drugs e.g anticoagulants, TCAs

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15
Q

what is the MOA of paracetamol?

A

unclear
activation of descending serotinergic pathways possibly via 5HT3 receptor
mild inhibition of cylcooxygenase
inhibits reuptake of endogenous endocannabinoids increasing activation of cannabinoid receptors

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16
Q

what is the drug target for paracetamol?

A

not yet defined

17
Q

what are the main side effects of paracetamol?

A

very few effects

in overdose, severe hepatotoxicity

18
Q

how should the adverse GI effects for NSAIDs be avoided?

A

if any upper abdominal discomfort arises, stop any oral or topical use

19
Q

how do NSAIDs cause GI side effects?

A

the role of COX-1 includes protection of the stomach lining. this is achieved by increasing bicarbonate release, mucus production and blood flow in gastric mucosa
reducing the stomachs protection may cause discomfort and irritation, ulceration, bleeding, perforation

20
Q

why should those with osteoporosis not be prescribed PPIs and instead use H2 blockers?

A

increased risk of osteoporosis related fractures
potentially due to altering pH which calcium absorbance is dependent on normally, decreasing amount of calcium available for bone

21
Q

first management step of GORD

A

test for h.pylori first

22
Q

first line for h.pylori positive

A

PPI and clarithromycin + amoxicillin (triple therapy)

23
Q

first line for h. pylori negative

A

address risk factors e.g NSAIDs

if cant be stopped, consider misoprostol or selective COX2 inhibitor

24
Q

first line for GORD with no reversible cause long term

A

PPI

25
Q

2nd line for no reversible cause long term

A

H2 receptor antagonist

26
Q

what condition are NSAIDs contraindicated for?

A

asthma