CPTP 12-14

Question 1

Drugs that undergo substantial first pass metabolism in the liver

Answer 1

aspirin, GTN, ldopa, morphine, propranolol, salbutalol

Question 2

ABx to avoid in liver disease

Answer 2

chloramphenicol (BM suppression), erythromycin, tetracycline, anti TB combinations, nitrofurantoin

Question 3

effect on bioavailability of drugs with a high hepatic extraction ratio in liver disease

Answer 3

increased, as normally have a low oral bioavailability. must reduce dose

Question 4

dose alteration of high ER drugs given orally in liver disease

Answer 4

initial and maintenance doses reduced

Question 5

dose alteration of high ER drugs given IV in liver disease

Answer 5

normal initial dose, reduced maintenance dose

Question 6

dose alteration for low extracted drugs with low binding to albumin (which undergo first pass metabolism about ≤30%)

Answer 6

maintenance dose should be reduced in them. For low extracted drugs with high binding to albumin (≥90%) may represent an exception from the rule that hepatic clearance is determined by the activity of metabolising enzymes.

Question 7

what drugs should be avoided in severe liver disease (risk of hepatic encephalopathy)

Answer 7

drugs which precipitate constipation, sedatives, diuretics

Question 8

UGI bleeding severity scores

Answer 8

Blatchford and Rockall

Question 9

h.pylori tests

Answer 9

faecal antigen, serum antibody, carbon13 breath, CLO/endoscopic biopsy (rapid urease)

Question 10

electrolyte disturbance with PPIs

Answer 10

low Mg

Question 11

quadruple therapy for h.pylori eradication

Answer 11

for eradication failure (with PAC, PAM). omeprazole and 2 ABx (tetracycline and metronidazole)

Question 12

4 types of laxative

Answer 12

bulk forming, stimulant, stool softeners, osmotic

Question 13

what laxative commonly prescribed to prevent hepatic encephalopathy

Answer 13

lactulose

Question 14

e.g. of stimulant laxative

Answer 14

senna.

Question 15

e.g. of stool softeners

Answer 15

liquid paraffin, docusate.

Question 16

adverse effect of long term liquid paraffin

Answer 16

fat soluble vitamin - impaired absorption (D and A)

Question 17

what laxative required for opioid induced constipation

Answer 17

stimulant

Question 18

should you prescribe PPI pre-endoscopy

Answer 18

no as need to be off acid suppression medication for > 2 weeks prior to endoscopy

Question 19

hypylori treatment - how long do you continue PPI for

Answer 19

2 months

Question 20

risks ass with PPIs

Answer 20

low Mg, risk of c diff, acute interstitial nephritis, microscopic colitis

Question 21

are cox 2 inhibitors prothrombotic

Answer 21

yes

Question 22

role of thromboxane

Answer 22

platelet aggregation, vasoconstriction

Question 23

role of prostacyclin

Answer 23

inhibits platelet aggregation, vasodilator

Question 24

suspicion with low faecal elastase

Answer 24

pancreatic exocrine deficiency

Question 25

tx of c diff

Answer 25

metronidazole, vancomycin

Question 26

what is loperamide

Answer 26

opioid antimotility agent (antidiarrhoeal)

Question 27

loperamide contraindications

Answer 27

c diff (increases toxic megacolon risk)

Question 28

causes of primary constipation

Answer 28

hirschprungs, rectocele/prolapse, impaired pelvic floor relaxation

Question 29

corticosteroids mechanism of action

Answer 29

inhibit phospholipase A2