GI Pharmacology 💊 Flashcards
How do alginates and antacids work to reduce heart burn?
Antacids- buffering stomach acid
Alginates- increase stomach content viscosity and reduce reflux
Why are magnesium salts and aluminium salts used as antacids usually given in the same preparation?
Magnesium salts can cause diarrhoea and aluminium can cause constipation, if given together the effects balance out and reduce risk of ADR
Why should diabetics be cautious when taking medication for heart burn?
Some preparation have high sucrose concentration which could lead to hyperglycaemia in DM2
Why should people taking gaviscon have a dose of that at separate times to other medications?
It can reduce the absorption of many drugs
How does taking gaviscon affect aspirin excretion?
Can increase aspirin excretion as increased urine alkalinity
What are two example of proton pump inhibitors?
Lansoprazole and omeprazole
Which PPI would you give to someone also taking clopidogrel?
Lansoprazole
What are some ADRs of PPIs?
Abdominal pain, diarrhoea, constipation (common)
Headache, dizziness, drowsiness (rarer)
Which other drugs can PPIs increase the effects of and so would have to be monitored carefully?
Warfarin and phenytoin
Which transporters do PPIs irreversibly inhibit?
The H+/K+ ATPase in gastric parietal cells
What type of drug is ranitidine?
H2 (histaminergic) receptor antagonist
Although ranitidine is generally well tolerated what are possible side effects?
Diarrhoea and headache
What are some warnings for ranitidine?
Can mask symptoms of gastro-oesophageal cancer, renal impairment
What are some warning of lansoprazole and omeprazole?
May increase risk of osteoporosis and fracture risk in elderly, may mask symptoms of gastro-oesophageal cancer
What investigations would you use to confirm H. Pylori infection?
Urea breath test
What treatment would you use for H.pylori infection?
One week triple therapy of PPI and two antibacterial agents
E.g: lansoprazole, clarithromycin, amoxicillin
What drug is used as first line treatment of UC and what drug class does it belong to?
Mesalazine which is an aminosalicylates
What are examples of anti-motility drugs acting on intestinal opioid receptors?
Loperamide, codeine, morphine
What are some ADRs associated with anti-motility drugs?
Paralytic ileus, N+V
How do anti-motility drugs help to increase transit time?
Decrease smooth muscle tone and decrease peristalsis
What are two examples of osmotic laxatives?
Macrogol, lactulose
How do osmotic laxatives help ease constipation?
Draw water into the stool
What are examples of stimulant laxatives?
Bisacodyl, senna, docusate sodium
How do stimulant laxatives help ease constipation?
Enhance gut motility, increase water and electrolyte transfer in lower GI tract lumen
