Pharmacology Flashcards
side effect of CCBs and phenytoin
gingival hypertrophy due to biting own gums
three drug classes that reduce acid secretion
- proton pump inhibitors
- histamine H2 receptor antagonists
- muscarinic ACh receptor antagonists
example of a PPI
omeprazole
features of PPIs
- activated in an acidic environment
- repeat dosing required
what are PPIs used in?
- peptic ulcer
- GORD
- Zollinger-Ellison syndrome
examples of H2RAs
ranitidine
cimetidine
what are H2RAs used in?
peptic ulcer
reflux oesophagitis
example of ACh receptor antagonist
pirenzepine
use of ACh receptor antagonists
now obsolete
two mucosal strengtheners
- sucralfate
2. bismuth chealate
features of sucralfate
bind to positively charged ulcer base increasing mucus, etc.
features of bismuth chealate
toxic towards H. pylori (in combination with antibiotics and H2RAs)
what are laxatives
agents used to treat constipation
what are purgatives
agents used to promote evacuation
when should laxatives and purgatives not be used?
if there is a physical bowel obstruction
when should laxatives and purgatives be used?
- staining damaging to health (angina)
- defecation is painful (haemorrhoids)
- purge the bowel before surgery
- treat drug-induced or bedridden constipation
mechanism of action of bulk laxatives
indigestible polysaccharide polymers that improve stool consistency
example of a bulk laxative
methycellulose
examples of stimulant purgatives
- bisacodyl
- sodium picosulfate
mechanism of action of osmotic laxatives
poorly absorbed solutes
examples of osmotic laxatives
magnesium sulfate
magnesium hydroxide
sodium citrate
lactulose
examples of faecal softeners
docusate sodium orally
arachis oil as enema
two examples of glucocorticoids used in IBD
prednisolone
budesonide
which IBD are aminosalicylates used in?
UC
examples of aminosalicylates
- sulfasalazine
- mesalazine
- olsalazine
- balsalazide
drug and radiation-induced emesis
- chemotherapy and radiotherapy release 5-HT and substance P
- PONV (anaesthetic)
- dopamine agonists D2 receptor in CTZ e.g. levodopa
- morphine
- cardiac glycosides e.g. digoxin
six classes of anti-emetic drugs
- 5-HT3 receptor antagonists
- muscarinic ACh receptor antagonists
- histamine H1 receptor antagonists
- dopamine receptor antagonists
- NK1 receptor antagonists
- CB1 receptor agonists
examples of 5-HT3 antagonists
ondansetron
palonosetron
what are 5-HT3 antagonists used in?
- chemotherapy and radiation-induced emesis
- PONV
what happens in subsequent treatments of 5-HT3
become less effective (overcome by addition of corticosteroid and NK1 receptor antagonist)
adverse of 5-HT3 receptor antagonists
constipation
headaches
examples of muscarinic ACh receptor antagonists used in motion sickness
hyosine
scopolamine
what are muscarinic ACh receptor antagonists used in?
motion sickness (block at multiple sites)
adverse of muscarinic ACh receptor antagonists in motion sickness
block parasympathetic ANS causing blurred vision, urinary retention, dry mouth and sedation
examples of histamine H1 receptor antagonists
cyclizine
cinnarizine
what are histamine receptor antagonists used in?
- motion sickness
- acute labyrinthitis
- irritants in the stomach
what do histamine H1 receptor antagonists block?
vestibular nuclei
NTS
adverse of H1 receptor antagonists
CNS depression and sedation
examples of dopamine receptor antagonists
domperidone
metoclopramide
when are dopamine receptor antagonists used?
drug induced vomiting
GI disorders
mechanism of action of dopamine receptor antagonists
block D2 and D3 in CTZ
adverse of metoclopramide (crosses BBB)
disorders of movement
example of NK1 receptor antagonist
aprepitant
when are NK1 receptor antagonists used?
in combination with 5-HT3 and dexamethasone in delayed phase
example of CB1 receptor agonists
nabilone
when are CB1 receptor agonists used
if other chemo-induced emesis drugs are ineffective
example of anti-motility agents used in diarrhoea (morphine-like/opioid drugs)
- codeine
- loperamide
- diphenoxylate
when is ursodeoxycholic acid used?
dissolve small or medium sized gall stones
adverse of ursodeoxycholic acid?
diarrhoea
what is given to relieve biliary spasm
atropine
GTN
examples of bile acid sequestrants
colveselam
colestipol
colestyramine
mechanism of action of bile acid sequestrants
bind to bile acids and prevent there reabsorption
when are bile acid sequestrants used?
Hyperlipidaemia
cholestatic jaundice (itch)
bile acid diarrhoea
adverse of bile acid sequestrants
- diarrhoea
- reduced absorption of fat soluble vitamins and thiazides
describe hepatic encephalopathy
in hepatic failure detoxification of urea fails leading to toxic levels of NH3 affecting the CNS
two treatment options for hepatic encephalopathy
- lactulose
- antibiotics
role of lactulose in hepatic encephalopathy
converts NH3 to NH4+
antibiotics role in hepatic encephalopathy
suppress colonic flora and inhibit ammonia generation
examples of antibiotics used in hepatic encephalopathy
neomycin
rifamixin
