GORD

Question 1

Management of GORD

Answer 1

1. Reduce/suppress gastric acid secretion
2. Mucosal protection (barrier)
3. Neutralizing gastric acid
4. Eradicate H. Pylori

Question 2

Proton pump inhibitors mechanism

Answer 2

-prazole’s

• irreversible inhibition of H+/K+ ATPase enzyme (proton pump)
• suppress H+ ions into lumen

Omeprazole: only one that has significant drug interactions (inhibits CYP450) - toxic side effects from other drugs

Question 3

PPI side effects

Answer 3

• hypomagnesemia (in prolonged use
• risk of fractures and osteoporosis (incomplete absorption of calcium carbonate)
• clostridium difficile associated diarrhea NB
• prevent B12 absorbtion (acid required for absorbtion) -> anemia

Question 4

H2 receptor antagonists

Answer 4

Reversibly binds H2 receptors in parietal cells of stomach

-gastric acid secretion response to other secretagogues also reduced
(Food, caffeine, Ach, gastrin)

• nocturnal acid hypersecretion: useful
• or in people allergic to PPI’s

Question 5

H2 receptor antagonists SE

Answer 5

• not in pregnancy

- anti-androgenic effects

Question 6

Cimetidine

Answer 6

H2RA
-inhibits CYP450 - more interactions

-also can be used to Rx molluscum contagiosum

Question 7

Ranitidine

Answer 7

H2RA

• as effective as cimetidine, less SE and interactions
• little/no androgenic effects

Question 8

Prostaglandins

Answer 8

Inhibit HCl secretion, wtimulates mucus and bicarbonate secretion and vasodilation of submucosa

• Misoprostol
• USE only in NSAID induced ulcers

Question 9

Prostaglandin SE

Answer 9

• not in pregnancy (contraction of uterus)

- nausea & diarrhea

Question 10

Sucralfate

Answer 10

Mucosal protective agent

• sucrose hydrogen sulphat-aluminum complex
• forms paste like gel when in contact with HCl - barrier

-Don’t use with any other med (at least 2h) - forms unabsorbable complex

Question 11

Bismuth Subcitrate

Answer 11

High affinity for damaged tissue - coats

SE: blackening of tongue, stools
-renal faiure in prolonged Rx

Question 12

Alginates

Answer 12

-used in pregnancy

Question 13

Antacids

Answer 13

-doesn’t block acid production, but neutralizes

• aluminum hydroxide
• calcium carbonate
• magnesium
• sodium bicarbonate

Question 14

H. Pylori eradication

Answer 14

Triple therapy
-7-14d regimen

1. PPI (for 1mo)
Any two of following:
-clarithromycin 500mg bd
-amoxicillin 1g bd
Metronidazole 400mg bd
Levofloxacin if resistant to clarithromycin

PPI CI - then use ranitidine + bismuth

Question 15

Vomiting centre

Answer 15

5HT2 receptors
Achm receptors
H receptors

Question 16

Stomach & intestines

Answer 16

Stretch receptors
Chemoreceptors
5HT3 receptors

-projections to chemoreceptor trigger zone and vomiting centre

Question 17

Chemoreceptor trigger zone

Answer 17

D2 (central) receptors
5HT3 receptors
NK1 receptors (NB)

-projections to vomiting centre

Question 18

Vestibular system

Answer 18

Achm
H1 receptors

-projections to chemoreceptor trigger zone and vestibular center

Question 19

Antihistamines

Answer 19

-H1 blockers

Question 20

Antihistamines SE

Answer 20

Anticholinergic SE

Question 21

Promethazine

Answer 21

F

Question 22

Cyclizine

Answer 22

F

Question 23

Betahistine

Answer 23

D

Question 24

Cinnarizine

Answer 24

F

Question 25

Phenothiazines

Answer 25

Dopamine antagonists - most common general purpose anti-emetic - helpful in hiccups NBNB - numbs phrenic nerve which supplies diaphragm -extra pyramidal SE

Question 26

Benzamides

Answer 26

D

Question 27

Butyrophenones

Answer 27

F

Question 28

Domperidone

Answer 28

D

Question 29

Haloperidol

Answer 29

D

Question 30

Metoclopramide

Answer 30

Dopamine antagonist - 5HT4 stimulation (prokinetic) - 5HT3 antagonist at higher doses - promotes gastric emptying - all nausea except labyrinth disorders - anti dopamine effects: - extrapyramidal Sx

Question 31

5HT3 receptor antagonists

Answer 31

- chemotherapy induced emesis | - SE: headache, QT interval prolonged (monitor in heart disease)

Question 32

Ondansetron

Answer 32

F

Question 33

Granisetron

Answer 33

Ss

Question 34

Palonsetron

Answer 34

D

Question 35

Dolasetron

Answer 35

D

Question 36

Tropisetron

Answer 36

S

Question 37

Benzodiazepine

Answer 37

D

Question 38

Neurokinin Antagonists

Answer 38

Aprepitant -neurokinin 1 receptor in brain - blocks substance P in CTZ and vomiting centre - -

Question 39

Corticosteroids

Answer 39

Unknown mechanism of action - used with cytotoxic drugs - large doses - combo with NK1 Antagonists and 5HT3 antagonists

Question 40

Cannabinoids

Answer 40

Dronabinol and Nabilone - useful in cytotoxic therapy - blocks descending pathways in cortical centres

Question 41

Anti muscarinic agents

Answer 41

- decreased GI motlity and secretory activity - muscarinic receptor blocking in vomiting centre and vestibular centre -Don’t use in prostatic enlargement, or closed angle glaucoma, or intestinal obstruction

Question 42

Hyoscine

Answer 42

Anti-muscarinic - used in preventing motion sickness in short journeys - not for long term use! -can be used to relieve smooth muscle spasms (intestinal, biliary, or genitourinary)

Question 43

Antimuscarinic SE

Answer 43

Think - fight or flight - cardiac arrhytmias - dry mouth - constipation - urinary retention - respiratory collapse/apnoea