Pharmacology

Question 1

How does histamine increase acid secretion

Answer 1

Binds to H2 receptor to activate adenylyl cyclase

increase cAMP to increase number of proton pumps expressed on parietal cell

Question 2

How does ACh increase acid secretion

Answer 2

binds to M3 receptors to activate PLC

increases intracellular calcium to increase proton pump expression

Question 3

how does gastrin increase acid secretion

Answer 3

binds to CCK2 receptors to activate PLC

increases intracellular calcium to increase number of proton pumps available

Question 4

how does somatostatin decrease acid production

Answer 4

binds to SST2 receptors to inhibit adenylyl cyclase
decrease cAMP to decrease proton pump expression
binds to SST2R on enterochromaffin-like cell to decrease histamine

Question 5

how do antacids reduce the symptoms of acid reflux

Answer 5

buffers HCl by dissociating to form bicarbonate and binding to H to form carbonic acid, broken down to water and carbon dioxide

Question 6

how do NSAIDs increase acid production

Answer 6

inhibit prostaglandin production by inhibition of COX-1

increases histamine production

Question 7

treatment of NSAID induced peptic ulcer and side effects

Answer 7

misoprostol - analogue of prostaglandin E1

abdominal pain, diarrhoea, induction of labour

Question 8

how do proton pump inhibitors work?

Answer 8

irreversibly bind to proton pump to inhibit secretion of H and formation of HCl

Question 9

name 3 proton pump inhibitors and their indication and side effect

Answer 9

lansoprazole, omeprazole, pantoprazole
gastric acid ulcer, NSAID peptic ulcer, gastro-oesophageal reflux, zollinger ellison disease
increase chance of infection

Question 10

how do H2 receptor antagonists work?

Answer 10

block H2 receptor to block histamine release

Question 11

name 3 H2 antagonists and indication/side effect

Answer 11

ranitidine, cimetidine, famotidine
gastric acid ulceration/NSAID ulceration
sexual dysfunction in men

Question 12

explain how H pylori causes ulceration

Answer 12

migrate to mucus layer where pH is higher and causes mucus cells to die
pH lowers due to destruction of mucus layer so ulceration occurs

Question 13

treatment of H pylori infection

Answer 13

antibioics

proton pump inhibitors

Question 14

How does the chemoreceptor trigger zone know when to invoke vomiting

Answer 14

BBB in CTZ is permeable so toxins in that area may activate it

Question 15

what does the vomiting centre of the brain do?

Answer 15

collects afferents to evoke vomit reflex

Question 16

antiemitic antihistamines, name and mechanism

Answer 16

cyclizine, promethzane, diphenydramine

antagonists of H1 in brain

Question 17

antiemitic antihistamines - indication and side effects

Answer 17

nausea, vomiting and motion sickness

sedation

Question 18

antiemitic muscarinics, name, mechanism, indication, side effects

Answer 18

scopolamine
M1 antagonists at brain
motion sickness
tachycardia, dry mouth, constipation

Question 19

name of 5-HT3 receptor antagonists and side effects

Answer 19

ondansetron, granisetron, palonosetron

constipation, diarrhoea, headache

Question 20

mechanism of 5-HT3 receptor antagonists

Answer 20

inhibit 5-HT3 receptors in CTZ of medulla in hindbrain and GI tract

Question 21

mechanism of neurokinin-1 receptor antagonists

Answer 21

block substance P binding to NK-1 receptors in GI tract and CTZ to prevent vomiting

Question 22

name of neurokinin-1 receptor antagonists and side effects

Answer 22

fosaprepitant, apreptant

constipation, headache

Question 23

name of dopamine receptor antagonists and side effects

Answer 23

chlorpromazine, droperidol, haloperidol, prochlorperazine, metoclopramide
diarrhoea and extrapyramideal side effects (not domperidone)

Question 24

mechanism of dopamine receptor antagonists

Answer 24

antagonist of D2 receptor in CTZ (not domperidone) and D2 receptors in GI tract

Question 25

name 2 anti-diarrhoea drugs and their side effects

Answer 25

loperamide, diphenoxylate

Question 26

name 3 laxatives

Answer 26

lspaghula husk, lactulose, senna

Question 27

circulatory changes in liver disease

Answer 27

low albumin stimulates RAAS and aldosterone, endothelin ADH to cause Na and H2O retention
decreased renal clearance, ascites

Question 28

why are NSAIDs contraindicated in liver disease

Answer 28

cuts renal PGE synthesis so worsens renal congestion and can cause HRS
further Na retention
always give PPI

Question 29

what opiate may be used in liver disease

Answer 29

fentanyl

Question 30

true/false - phase I drugs should be used more readily in liver disease

Answer 30

false - it should be phase II

Question 31

true/false - those who are drunk will sufer effect of paracetamol overdose worse

Answer 31

false - alcohol blocks breakdown of paracetamol phase I so not as high a toxicity

Question 32

best diuretic for ascites?

Answer 32

spironolactone

Question 33

what antibiotics should be avoided in liver disease

Answer 33

metronidazole - it doesnt get metabolised

aminoglycosides - they are nephrotoxic

Question 34

semi digested food in vomit suggests what type of bowel obstruction

Answer 34

gastric outlet

Question 35

bile stained vomit suggests what type of bowel obstruction

Answer 35

small bowel

Question 36

faeculent vomit suggests what type of bowel obstrcution

Answer 36

large

Question 37

a patient has been diagnosed with bowel obstruction. they present with erratic bowel habit and intermittent vomiting. is the obstruction complete or incomplete

Answer 37

incomplete