Drugs on the GI Tract Flashcards
What is Mesalazine? What is its MOA and list some SE
5-ASA - used as maintenance for mild/moderate UC
metabolised in intestinal mucosal wall + liver
scavengers of ROS
modulates PG and cytokine synthesis
PPAR-y agonist
poor absorption - PO = 20-30% and PR = 10-35%
nephrotoxicity, rash, make colitis worse, pancreatitis, pericarditis
What is Sulphasalazine? What is its MOA and list some SE
5-ASA - used as maintenance for mild/moderate UC
Around 90% of a dose of sulfasalazine reaches the colon, where most of it is metabolized by bacteria into sulfapyridine and mesalazine
nephrotoxicity, rash, make colitis worse, pancreatitis, pericarditis
What class of drugs do Olsalazine and Basalazide belong to?
5-ASA
How can steroids be used to treat IBD? What are their MOA and list some SE
induces remission of IBD flare ups - NOT MAINTENANCE
can be given PO/suppositories/enema/IV
activates GC receptor –> reduces IL-1, TNFa, IL-8 –> lowers NO levels –> prevents leucocyte migration –> immunosuppressive
hypertension, T2DM, central obesity, osteoporosis, myopathy, acne, bruising, depression, adrenal/pituitary suppression, sepsis
What is Budesonide?
glucocorticosteroid receptor agonist
topical action - so less systemic side effects
What class of drug does omeprazole, lansoprazole, pantoprazole belong to? How do they work?
PPI
blocks H+/K+ ATPase –> prevents H+ secretion into lumen from gastric parietal cells
What the SE of taking PPIs?
headache nausea diarrhoea abdominal pain fatigue dizziness increased risk of C.Diff
What is Ranitidine? What is its MOA and SE?
H2 receptor antagonist
results in decreased gastric acid secretion and gastric volume, and reduced hydrogen ion concentration
malaise dizziness arrhythmias hepatitis thrombocytopenia pneumonia
What is Cyclizine?
H1 receptor antagonist + anticholinergic
used for vertigo, motion sickness, post-op nausea/vomiting
works at chemotrigger zone (CTZ) + labyrinth
SE: drowsiness, dry mouth, urinary retention
What is Metoclopramide?
D2 receptor antagonist + 5-HT4 receptor agonist
used for anti-emesis, gastroparesis, PONV
works at CTZ + increases gastric emptying
SE: restlessness, dystonic reactions
What is Ondasterone?
5-HT3 receptor antagonist
used for refractory PONV + chemotherapy
works on CNX, CTZ, peripheral efferents
SE: constipation, headache, flushing, bradycardia, hypotension
What is Azathioprine? What dose is it given in and what form?
immunosuppressive - inhibits purine synthesis
metabolised into mercaptopurine + thioguanine
used 2nd line as IBD maintenance
2mg/kg/day - PO
What are some SE of azathioprine?
liver damage + pancreatitis (from sub-product methyl-mercaptopurine) lethargy headache nausea rash viral infection lymphoma
What must you check before administering azathioprine?
TPMT status = thiopurine S-methyltransferase
low levels increase risk of high thioguanine levels –> bone marrow suppression
What is Fybogel?
Bulk laxative
MOA: increases stool mass –> stimulates peristalsis
SE: flatulence + bloating
