Pharmacology Flashcards
why is histamine released
in response to Ach
what does histamine do
activates adenylyl cyclase > inc cAMP > inc proton pumps > inc gastric secretion
why is Ach released?
parasympathetic cholinergic neurones
other than histamine release, what does Ach do?
binds to parietal cells activating PLC and causing inc Ca2+ which causes an inc in proton pump action
what is gastrin’s action?
binds to CCK2 Rs activating PLC causing inc Ca2+ > inc proton pump action > inc gastric secretions
what is the pathophysiology of vomiting
reverse peristalsis =
toxic material in gut > enterochromaffin cells in mucosa release mediators > sensory afferent nerves activated > AP discharged to brainstem > co-ordination by vomiting centre
causes of vomiting?
toxic material, mechanical stimuli, vestibular system, stimuli within CNS
what is the main zone for emetic stimuli?
chemoreceptor trigger zone
which receptors activate chemoreceptor trigger zone?
dopamine and Ach
what is big risk of NSAID abuse?
liver failure & GI ulcer
for patients with cirrhosis/ liver disease, what is the Moto for drug prescription?
start low, go slow
give renal excretion medicine
what are the 4 drugs that control gastric secretion?
PPIs, NSAIDs, Histamine H2 receptor antagonists, alginates and antacids
name 2 PPIs?
omeprazole and iansoprazole
which drug inhibits proton pump so reduces HCl secretion?
PPIs
how are PPIs given
oral or IV
what are PPIs given for?
peptic ulcers, GORD, helicobacter pylori
True/False…
PPIs inc chance of GI tract infection
True
named example of NSAID?
misoprostol
action of NSAIDs?
inhibits COX-1 so less prostaglandins to inc histamine promoting HCl secretion
what are NSAIDs used for?
inflammation e.g. IBD
common side effect of NSAIDs?
abdominal pain and ulcers
named example of histamine H2 receptor antagonist…?
ranitidine
action of histamine H2 receptor antagonist?
blocks H2 receptor dec HCl secretion
what is histamine H2 receptor antagonist given for?
gastric ulcers, NSAID associated ulcers
what are named exampled of antacids and alginates?
gavsicon, peptac, mucogel
what is the action of antacids?
buffers HCl
what are antacids typically given for?
GORD
what are the 9 anti-motility drugs including antidiarrhoeals
antimuscarinic drugs anti motility drugs amino salicylic acid steroids anti-TNF therapy immunosuppressants laxatives - bulk forming laxatives- osmotic laxatives- stimulant
what is an example of antimuscarinic drugs?
buscopan and atropine
what do antimuscarinic drugs do?
blocks muscarinic Ach receptors
what are antimuscarinics given for?
relieve SM spasm, IBS
what is of note of antimuscarinic drugs?
should be given cautiously in patients with arrhythmias
what are antimotility drug examples?
loperamide, codeine phosphate
what do drugs like loperamide do?
electrolyte replacement
when are anti motility drugs given?
acute diarrhoea, IBS
what must be excluded before prescribing anti motility drugs?
c.diff infection
give named examples of amino salicylic acids?
mesalazine, balsalazide, sulphasalazine
what is amino salicylic acid given for?
UC, occasionally RA
give named examples of steroids?
Prednisolone, hydrocortisone
what are steroid’s action?
anti-inflammatory
what are 5 side effects of steroids
osteoporosis, wt gain, thinning of skin, HT, cataracts, diabetes
how does anti-TNF alpha therapy act?
blocks pro-inflammatory cytokines and induces apoptosis of T cells
what are 2 examples of immunosuppressants?
methotrexate, azathioprine
what are 3 side effects of immunosuppressants?
pancreatitis, leucopaenia, hepatitis
what is an example of bulk forming laxatives?
ispagula husk
what are laxatives given for?
constipation, faecal impaction
what are examples of osmotic laxatives?
lactulose, phosphate enemas, senna
what are examples of stimulant laxatives?
Senna, glycerol suppository, sodium pico sulphate
which of the 3 types of laxatives is given for chronic diarrhoea due to diverticular disease/ IBS?
bulk forming laxatives
what are the 6 anti emetic drugs?
dopamine D2 receptor antagonists anti-muscarinics histamine H1 receptor antagonists phenothiazines 5-HT3 receptor antagonist neurokinin-1 R antagonist
give 3 named examples of dopamine D2 receptor antagonists?
domperidone, metoclopramide, chlorpromazine
what are dopamine D2 receptor antagonists tx for?
nausea and vomiting, GORD for pts who don’t respond to PPIs
anti muscarinic named example as anti-emetic?
scopolamine
what are anti-muscarinics used for in anti-emetic terms?
motion sickness
what are 2 named examples of histamine H1 receptor antagonists
cyclizine, cinnarizine
what are histamine H1 receptor antagonists typically used for to treat?
vertigo
chlorpromazine is an example of which anti-emetic drug?
phenothiazines
what are phenothiazines used for?
nausea due to chemo
what are ondanesteron and palonesterone examples of?
5-HT3 receptor antagonist
- these must be given cautiously !
fossaprepitant and apreptant are examples of…?
NK-1 receptor antagonists
