GI Flashcards
Antacid
increases gastric pH
- when gastric HCl reaches nerves in GI mucosa, signals pain to CNA
- forms a thick layer coating the stomach contents to prevent reflux
example of antacid
gaviscon
when to give antacids
GORD, heartburn, acid indigestion, peptic ulcers
contra-indications for antacids
hypersensitivity to active substances
side-effects of antacids
rare - drowsiness, dizziness, nausea, vomiting, dry mouth, diarrhoea, abdomen pain, cramps
possible interactions of antacids
ACEi + Ca carbonates, digoxin - antacid decreases absorption of these
H2 antagonists
reduces gastric acid secretion via blocking parietal cells -blocks histamine receptors so histamine cannot be released and this is what activates the proton pump on parietal cells
example of H2 antagonist
ranitidine
when to give H2 antagonists
benign gastric and duodenal ulceration, dyspepsia, GORD, prophylaxis of stress ulceration, peptic ulcer disease
contra-indications for H2 antagonists
hypersensitivity, gastric cancer, renal impairment
side effects of H2 antagonist
diarrhoea, GI disturbance, altered LFTs, headache, dizziness, rash, tiredness
how are H2 antagonists eliminated?
renal
proton pump inhibitor
suppresses gastric acid secretion by inhibiting H+/K+/ATPase parietal cell
example of proton pump inhibitor
omeprazole / lanzoprazole
when to give PPIs
peptic ulcers, GORD, dyspepsia, ulcerating reflux oesophagitis
contra-indications for PPIs
hypersensitivity, gastric cancer, liver disease
side effects of PPIs
GI disturbance (N+V, diarrhoea, flatulance, constipation), headache, agitation, impotence
possible interactions of PPIs
increases plasma concentration of digoxin
decreases anti-coag effect of clopidrgral
how are PPIs eliminated
hepatic
anti-diarrhoeal agent
opiod agonist which acts on the u-receptors in the GI tract, decreasing peristaltic movements, decreasing motility, allowing bowel substances to spend longer time on the bowel, more time for water absorption
examples of anti-diarrhoeal agents
loperamide
when to give loperamide
diarrhoea
contra-indications for loperamide
when peristalsis inhibition should be avoided, abdominal distension, ulcerative colitis, dysentry diarrhoea
side effects of loperamide
abdo cramps, dizziness, drowsiness, skin reactions, paralytic ileum, bloating
stimulant laxative
increases intestinal motility to loosen the stool (does this by increased electrolyte and water secretion, increasing the volume of colonic contents, increasing peristaltic contractions)
example of stimulant laxative
senna
when to give a senna
constipation
contra-indications of stimulant laxative
intestinal obstruction
side-effects of sennas
abdo cramps, diarrhoea, hypokalaemia (diarrhoea decreases vita absorption)
elimination of senna
renal - given at night
interactions of sennas
diuretics – Senna depletes Na,
warfarin - diarrhoea decreases absorption of vitamins K and increases bleeding risk
aminosalicyclate
diminishes inflammation by blocking cyclooxygenase and inhibiting prostaglandins production in the colon
examples of aminosalicyclate
mesalazine
indications for aminosalicyclate
ulcerative colitis
contra-indications for aminosalicyclate
salicylate hypersensitivity, renal function should be monitored, blood disorders may occur
side effects of aminosalicyclate
diarrhoea, nausea, vomiting, abdo pain, exacerbation of colitis symptoms, headache, hypersensitivity rash
