Pharmacology

Question 1

how are HCO3- and H+ produced

Answer 1

from carbonic acid

Question 2

what ion is HCO3- pumped out of the parietal cell in exchange for

Answer 2

Cl-

Question 3

H+/K+ ATPase also called

Answer 3

proton pump

Question 4

3 receptors on parietal cells

Answer 4

M3 - ACh
G/CCK2 - gastrin
H2 - histamine
all cause increases acid secretion when bound

Question 5

making HCl in parietal cells

Answer 5

carbonic acid is produced by water and CO2 via carbonic anhydrase
HCO3- and H+ are produced
HCO3- is puped out of the cell in exchange for Cl- which are pumped into the canaliculus
H+ and Cl- make HCl

Question 6

PPI

Answer 6

irreversibly inhibits the proton pump
decrease in HCl production
taken 20 mins before eating

Question 7

why are PPI taken 20 minutes before eating

Answer 7

same time frame for proton pumps to move to the canalicular membrane before digestion

Question 8

PPI examples

Answer 8

omeprazole
lanoprazole
pantaprazole

Question 9

PPI side effects

Answer 9

less acidic stomach reduced defence against infection
masks symptoms of gastric malignancy
risk osteoporosis

Question 10

H2 receptor antagonists

Answer 10

blocks H2 receptors so histamine cannot act on the parietal cell
decrease proton pumps
decrease HCl production
less effective than PPI

Question 11

H2 receptor antagonist examples

Answer 11

Ranitidine
cimetidine
famotidine
nizatidine

Question 12

H2 receptor antagonist side effects

Answer 12

masks symptoms of gastric malignancy

Question 13

compound alginates

Answer 13

have antacid and alginate function
buffer HCl and make pH in the stomach more neutral (antacid)
increase the viscosity of gastric juice, react with acid to produce a foam layer that protects the oesophagus (alginates)

Question 14

compound alginates examples

Answer 14

peptac
gaviscon
mucogel

Question 15

prostaglandins and somatostatin

Answer 15

reduce the effect of the secretagogues and inhibit gastric acid secretion

Question 16

NSAIDs

Answer 16

inhibit COX 1 which affects prostaglandin production
less prostaglandin is available so increase HCl
increased risk of peptic ulcer

Question 17

NSAIDs examples

Answer 17

aspirin
ibuprofen
diclofenac
naproxen

Question 18

misoprostol

Answer 18

prostaglandin E1 analogue

prophylaxis for NSAIS induced peptic ulcer

Question 19

diarrhoea

Answer 19

loss of fluid and solutes from the GI tract making stool loose and watery > 3 loose stools in 24hrs
leads to dehydration

Question 20

causes of diarrhoea

Answer 20

activation of CFTR - - more Cl is secreted and Na and water follow
impaired absorption of NaCl - water can’t follow NaCl into the blood so there more water in the lume
non-absorbable or poorly absorbable solutes in the lumen
hypermotility - lumenal contents progree too rapidly down GI tract meaning reduced absorption

Question 21

synthetic opioids

Answer 21

agonist of the opioid receptors expressed by the enteric neurons
inhibit the enteric nervous system
decreased peristalsis and increased segmentation
increased fluid absorption
overall having constipating effect

Question 22

synthetic opioids examples

Answer 22

loperamide - imodium
codeine phosphate
diphenoxylate

Question 23

synthetic opioids contraindications

Answer 23

ABCD
acute UC - risk of megacolon and perforation
babies - don't give to children 
C.diff colitis 
dysentery - bloody diarrhoea

Question 24

rehydration therapy

Answer 24

fluid and electrolyte replacement is essential in diarrhoea treatment as patients lose lots of electrolytes and water
Na and glucose in the rehydration salts is absored via SGLT1 water follows them and is absorbed too

Question 25

constipation

Answer 25

passage of <2 bowel movements a week often passed with difficulty straining or pain and a sense of incomplete evacuation there is a delay in defaecation and enhanced absorption of water presence of hard, dried faeces within the colon

Question 26

causes of constipation

Answer 26

lack of fibre and fluid intake lack of physical activity drugs - opioids obstruction

Question 27

laxatives bulking

Answer 27

indigestible by the small intestine so add to the faecal mass cause the stool to absorb water increase bulk of the stool - peristalsis is stimulated

Question 28

bulking laxative examples

Answer 28

ispaghula husk methylcellulose sterculia

Question 29

bulking laxatives contraindications

Answer 29

bowel obstruction | ileus

Question 30

osmotic laxatives

Answer 30

cause osmosis - by osmosis, water travels into the stool | increase bulk of the stool - peristalsis is stimulated

Question 31

osmotic laxatives examples

Answer 31

lactulose macrogols phosphate enema citrate enema

Question 32

osmotic laxatives contraindications

Answer 32

bowel obstruction | heart failure, ascites, electrolyte disturbances - phosphate enema

Question 33

stimulant laxatives

Answer 33

stimulate intestinal motility and intestinal secretion increase mucosal electrolyte and water secretion into intestinal lumen, stimulate enteric nerves increse bulk of the stool - peristalsis is stimulated increased intestinal motility - increase stool movement through the intestine

Question 34

stimulant laxatives examples

Answer 34

``` senna glycerol suppository bisacodyl docusate sodium sodium picosulfate ```

Question 35

stimulant laxatives contraindications

Answer 35

bowel obstruction | prolonged use - atonic colon

Question 36

stimulant laxatives side effects

Answer 36

abdominal pain