CPTP 12-14 Flashcards
Drugs that undergo substantial first pass metabolism in the liver
aspirin, GTN, ldopa, morphine, propranolol, salbutalol
ABx to avoid in liver disease
chloramphenicol (BM suppression), erythromycin, tetracycline, anti TB combinations, nitrofurantoin
effect on bioavailability of drugs with a high hepatic extraction ratio in liver disease
increased, as normally have a low oral bioavailability. must reduce dose
dose alteration of high ER drugs given orally in liver disease
initial and maintenance doses reduced
dose alteration of high ER drugs given IV in liver disease
normal initial dose, reduced maintenance dose
dose alteration for low extracted drugs with low binding to albumin (which undergo first pass metabolism about ≤30%)
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.
what drugs should be avoided in severe liver disease (risk of hepatic encephalopathy)
drugs which precipitate constipation, sedatives, diuretics
UGI bleeding severity scores
Blatchford and Rockall
h.pylori tests
faecal antigen, serum antibody, carbon13 breath, CLO/endoscopic biopsy (rapid urease)
electrolyte disturbance with PPIs
low Mg
quadruple therapy for h.pylori eradication
for eradication failure (with PAC, PAM). omeprazole and 2 ABx (tetracycline and metronidazole)
4 types of laxative
bulk forming, stimulant, stool softeners, osmotic
what laxative commonly prescribed to prevent hepatic encephalopathy
lactulose
e.g. of stimulant laxative
senna.
e.g. of stool softeners
liquid paraffin, docusate.
