Gastro

Question 1

What are the common uses of spironolactone?

Answer 1

to treat ascites and oedema due to liver cirrhosis
to treat chronic heart failure
to treat primary hyperaldosteronism

Question 2

What is the mechanism of action of spironolactone?

Answer 2

Aldosterone antagonist

- increases sodium and water excretion and increases potassium retention by acting on distal tubules

Question 3

What are important adverse reactions of spironolactone?

Answer 3

hyperkalaemia
gynaecomastia
liver impairment
jaundice

Question 4

What are the warning for spironolactone?

Answer 4

renal impairment, hyperkalaemia, Addison’s disease, pregnant or lactating

Question 5

What are important interactions for spironolactone?

Answer 5

any K+ elevating drugs - ACE-i, ARBs, potassium supplements

Question 6

What are indications for giving azathioprine?

Answer 6

to maintain remission in IBD
disease modifying drug in autoimmune e.g. RA
to prevent organ rejection

Question 7

What is the mechanism of action of azathioprine?

Answer 7

stops DNA and RNA replication in lymphocytes

Question 8

What are some warnings of azathioprine?

Answer 8

should not be prescribed in absent TPMT activity
caution in liver or renal impairment, pregnancy
caution in previous hypersensitivity reaction

Question 9

What are some interactions of azathioprine?

Answer 9

+corticosteroids = increased risk of infection
not prescribed with xanthine oxidase inhibitors e.g. allopurinol
trimethoprim increases chance of leukopenia
azathioprine can reduce effect of warfarin

Question 10

What are examples and indications of alginates and antacids?

Answer 10

gaviscon or peptac

GORD, dyspepsia

Question 11

What is the mechanism of alignates and antacids?

Answer 11

antacids - buffer stomach acids

alignates - increase viscosity of stomach contents, which reduces reflux

Question 12

What are some adverse reactions of alignates and antacids?

Answer 12

GI upset

Question 13

What are some cautions of alignates and antacids?

Answer 13

in children, do not give with thickened foods
caution with renal failure
can worsen hypoglycaemia

Question 14

What are some interactions with alignates and antacids?

Answer 14

can bind to other drugs and reduce absorption so give drugs 2 hours after (esp. antibiotics, ACE-i, bisphosphonates)
can increase excretion of aspirin and lithium

Question 15

What are names of aminosalicylates and how do they work?

Answer 15

mesalazine, sulfasalazine

they have antiinflammatory and immunosuppressive effects

Question 16

What are the indications of aminosalicylates?

Answer 16

UC and RA

Question 17

What are adverse effects of aminosalicylates?

Answer 17

GI upset, headache, renal impairment, oligospermia, hypersensitivity

Question 18

What are warnings of aminosalicylates?

Answer 18

aspirin hypersensitivity - mesalazine and sulfasalazine are salicylates, like aspirin

Question 19

What are important interactions of aminosalicylates?

Answer 19

mesalazine is pH coated so things that effect pH interact - PPIs, lactulose

Question 20

What are the 3 groups of antiemetics?

Answer 20

Histamine antagonists - cyclizine
Serotonin antagonists - ondansteron
dopamine (D2) antagonist - domperidone, metoclopramide
DON’T USE METOCLOPRAMIDE IN PD

Question 21

What are domperidone and metoclopramide used for and how do they work?

Answer 21

To reduce nausea and vomiting (antiemetic) especially in context of reduced gut mobility
D2 receptor antagonists

Question 22

What are some SE of domperidone and metoclopramide?

Answer 22

diarrhoea

metoclopramide - extrapyramidal symptoms - do not give in PD

Question 23

What are some warnings for D2 antagonist antiemetics?

Answer 23

Don’t give in young people, people at risk of cardiac problems (it prolongs QT interval)
don’t give metoclopramide in PD as it crosses blood-brain barrier

Question 24

What is cyclizine and how does it work?

Answer 24

antiemetic - especially in context of vertigo

histamine receptor antagonist

Question 25

What are some SE of cyclizine?

Answer 25

dry mouth tachycardia drowsiness

Question 26

What are some warnings of cyclizine?

Answer 26

don't give with hepatic encephalopathy don't give with other sedative drugs don't give in prostatic hyperplasia

Question 27

Give some examples of anti-motility drugs, what they are used for and how they work?

Answer 27

loperamide and codeine phosphate to treat diarrhoea both act on u-receptors - loperamide only in gut so no analgesia (preferable)

Question 28

What are some adverse effects of anti-motility drugs?

Answer 28

type A (augmented) effects - GI problems e.g. constipation, cramps, flatulence

Question 29

What are some warnings and interactions with anti-motility drugs?

Answer 29

don't give loperamide if UC, C. diff or bloody diarrhoea | Don't give codeine unless analgesic effect is required

Question 30

What is the common H2-receptor antagonist, what is it used for and how does it work?

Answer 30

ranitidine peptic ulcer disease, GORD, dyspepsia it reduces gastric acid secretion

Question 31

What are adverse reactions of ranitidine?

Answer 31

very few SE | bowel disturbance, headache, dizziness

Question 32

What are some warnings and interactions of ranitidine?

Answer 32

excreted by kidneys so reduce dose in renal impairment can disguise symptoms of gastro-oesophageal cancer no significant interactions

Question 33

What are some examples of osmotic laxatives, what are they used for and how do they work?

Answer 33

lactulose, macrogel, phosphate enema used for constipation, faecal impaction, bowel preparation, hepatic encephalopathy they are osmotically active substances so hold water in stool, keeping volume and stimulating peristalsis. Lactulose reduces ammonia absorption so good for liver failure which has led to hepatic encephalopathy

Question 34

What are some adverse effects of osmotic laxatives?

Answer 34

flactulance, abdo cramps, nausea, diarrhoea | phosphate enema - local irriation, electrolyte disturbances

Question 35

What are some cautions and important interactions of osmotic laxatives?

Answer 35

intestinal obstruction as risk of perforation phosphate enemas - fluid shifts so shouldn't be sued in heart failure, ascites, electrolyte disturbances no significant interactions but effect of warfarin could be increased

Question 36

What are some examples of stimulant laxatives, what are they used for and how do they work?

Answer 36

senna, bisacodyl, glycerol suppositories, docusate sodium used for constipation, suppositories can be used for faecal impaction encourage water and electrolyte secretion from colonic mucosa so increase volume of colonic content and stimulate peristalsis

Question 37

What are some adverse effects of stimulating laxatives?

Answer 37

abdominal pain, cramping, diarrhoea

Question 38

What are some cautions and interactions of stimulating laxatives?

Answer 38

don't give when intestinal obstruction as can induce perforation, avoid suppositories in haemorrhoids and anal fissures no interactions