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Flashcards in GI Deck (20)
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1

H2 Antagonists: Mechanism of Action

Block histamine receptor on parietal cells. Usually histamine activates the proton pump. There are alternate mechanisms so they are not as completely suppressive as PPIs

2

H2 Antagonists: Indications

PUD, GORD, Dyspepsia

3

H2 Antagonists: Side effects

Generally well tolerated, diarrhoea, constipation, headaches

4

H2 Antagonists: Interactions and Warnings

No major interactions
Really excreted, so reduce dose in renal impairment
Can mask signs of gastric cancer

5

H2 Antagonists: Prescribing

Short term use = OTC
No monitoring
Therapy is guided by symptoms

They have generally been superseded by PPIs, but they do have a faster onset

6

PPI: Mechanism of Action

Irreversibly inhibit H+/K+ATPase in parietal cells so reduced acid production

7

PPI: Indications

First line therapy for PUD, GORD, dyspepsia
H.Pylori eradication, as part of triple therapy

8

PPI: Side Effects

GI Disturbance, headaches, some evidence of increases C.diff risk

9

PPI: Interactions and Warnings

Omeprazole can decrease the efficacy of clopidogrel. Other PPIs have less of an effect.
They can mask the symptoms of GI cancer
Can increase the risk of osteoporosis

10

PPI: Prescribing

Oral or injectable available

11

Mesalazine: Mechanism of Action

It is an aminosalycilate drug. It acts be releasing 5-ASA. Its precise mechanism is unknown, but it acts locally on the gut and has anti-inflammatory and immunosuppressive effects.

12

Mesalazine: Indications

Mild to moderate UC (First line drug)

13

Mesalazine: Side Effects

Nausea, dyspepsia, headache
Rare but serious: renal impairment, leukopenia, thrombocytopenia

14

Mesalazine: Interactions and Warnings

Tablets with a pH sensitive coating may be affected by changes in gastric pH
ASPIRIN ALLERGY!

15

Mesalazine: Prescribing

Oral or suppository
Renal function should be checked for safety
Efficacy is guided by symptoms

16

Loperamide: Mechanism of Action

It is an opioid and is chemically similar to pethidine. However, it does not penetrate the CNS so has no analgesic properties. It agonises GI mu-opoid receptors. It slows peristaltic contractions and increases anal tone. The increased transit time means more water can be reabsorbed.

17

Loperamide: Indications

Diarrhoea, usually viral gastroenteritis or IBD

18

Loperamide: Side Effects

Predictable: constipation, cramping, flatulance

19

Loperamide: Interactions and Warnings

Should be avoided in acute ulcerative colitis (inc. risk of toxic megacolon and perforation). Should be avoided in C.Diff and with bloody diarrhoea (could be ETEC) because of the risk of HUS.

It has no clinically significant interactions.

20

Loperamide: Prescribing

Can be purchased OTC (probably will be cheaper for patient)
Monitored by symptomatic relief
Makes sure to mention it does not treat underlying cause.