gastrointestinal pharmacology - lower GI tracts Flashcards
what does the lower GI tract consist of - 4
small intestine
large intestine
mix of differentiated and stem cells
2kg of intestinal flora
what does the lining of the small intestine consist of
millions of microscopic projections called vili that inc sa for absorption of food particles
the intestinal walls contain __ and ___ receptors that allow intestine to response to food within it and propel food along
tension
stretch
drugs that affect motility of GI tract - 4
purgatives
agents that inc motility of GI smooth muscle
antidiarrhoel drugs (dec motility)
antispasmodic drugs (dec smooth muscle tone)
which type of drugs that affect motility of GI tract specifically treat constipation - 2
purgatives
agents that inc motility of GI smooth muscle
which type of drugs that affect motility of GI tract specifically treat diarrhoea - 2
antidiarrhoel drugs (dec motility)
antispasmodic drugs (dec smooth muscle tone)
constipation cause
dec movement of fecal matter along GI tract
dec freq of bowel movements
constipation general treatments - 2
usually dietary modification
if fails, laxatives used (unless obstruction of bowel) (also abuse of laxatives is number 1 cause of constipation)
morphine can contribute to constipation
laxatives types/ constipation pharmacological therapies - 4
bulking agents
osmotic laxatives
stimulant laxatives
faecal softeners
bulking laxative agents examples - 4
agar
bran
methylcellulose
ispaghula husk
bulking laxative agents admin
insoluble and non absorbable, non digestive so must be taken with lots of water unless will worsen constipation
saline and osmotic laxatives mechanism of action
fluid is drawn into bowel by osmotic force, increasing volume and triggering peristalsis
used to purge large intestine after surgery and poisioning
fast acing - 1-3 hours
saline and osmotic laxative agents are usually ___
nondigestible
saline and osmotic laxative agent example
non digestable sugars and alcogols e.g lactulose
lactulose
semi synthetic disaccharide, broken down by bacteria in GI tract to acetic and lactic acid which cause osmotic effect
saline and osmotic laxative salts examples - 5
milk of magnesia (Mh(OH)2)
epsom salt (MGSO4)
glauber’s salt (Na2SO4)
sodium phosphates (admin as enema)
sodium citrate (admin as enema)
saline and osmotic laxative other examples (not sugars, salts, or alcohols) - 2
polyethylene glycol and vitamic c
saline and osmotic laxative side effects - 2
flatulence
cramping
emollients
faecal softeners
emollient examples - 4
docusate sodium (surfactant and stimulant) suppositories
glycerin suppositories (mildly irritable, inc movement)
groundnut oil, peanut oil
liquid paraffin oral solution
liquid paraffin side effect - 2
anal seepage
granulomatosis of GI - which is necrotizing vasculitis
irritant/ stimulant laxatives mechanism of action
inc peristalsis, inc intestinal motility by stimulating enteric system nerves
irritate GI mucosa and pulls water into lumen
indicated for severe constipation where more rapid effect is required (6-8 hrs)
irritant/ stimulant laxatives/ cathartics examples - 4
castor oil
bisacodyl
lubiprostone
anthraquinones
lubiprostone
PGE1 derivative that srimulates chloride channels, producing chloride like secretions, helps fecal matter being propelled