gastrointestinal pharmacology - lower GI tracts Flashcards

1
Q

what does the lower GI tract consist of - 4

A

small intestine
large intestine
mix of differentiated and stem cells
2kg of intestinal flora

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2
Q

what does the lining of the small intestine consist of

A

millions of microscopic projections called vili that inc sa for absorption of food particles

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3
Q

the intestinal walls contain __ and ___ receptors that allow intestine to response to food within it and propel food along

A

tension

stretch

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4
Q

drugs that affect motility of GI tract - 4

A

purgatives

agents that inc motility of GI smooth muscle

antidiarrhoel drugs (dec motility)

antispasmodic drugs (dec smooth muscle tone)

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5
Q

which type of drugs that affect motility of GI tract specifically treat constipation - 2

A

purgatives

agents that inc motility of GI smooth muscle

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6
Q

which type of drugs that affect motility of GI tract specifically treat diarrhoea - 2

A

antidiarrhoel drugs (dec motility)

antispasmodic drugs (dec smooth muscle tone)

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7
Q

constipation cause

A

dec movement of fecal matter along GI tract

dec freq of bowel movements

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8
Q

constipation general treatments - 2

A

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

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9
Q

laxatives types/ constipation pharmacological therapies - 4

A

bulking agents

osmotic laxatives

stimulant laxatives

faecal softeners

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10
Q

bulking laxative agents examples - 4

A

agar

bran

methylcellulose

ispaghula husk

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11
Q

bulking laxative agents admin

A

insoluble and non absorbable, non digestive so must be taken with lots of water unless will worsen constipation

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12
Q

saline and osmotic laxatives mechanism of action

A

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

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13
Q

saline and osmotic laxative agents are usually ___

A

nondigestible

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14
Q

saline and osmotic laxative agent example

A

non digestable sugars and alcogols e.g lactulose

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15
Q

lactulose

A

semi synthetic disaccharide, broken down by bacteria in GI tract to acetic and lactic acid which cause osmotic effect

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16
Q

saline and osmotic laxative salts examples - 5

A

milk of magnesia (Mh(OH)2)

epsom salt (MGSO4)

glauber’s salt (Na2SO4)

sodium phosphates (admin as enema)

sodium citrate (admin as enema)

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17
Q

saline and osmotic laxative other examples (not sugars, salts, or alcohols) - 2

A

polyethylene glycol and vitamic c

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18
Q

saline and osmotic laxative side effects - 2

A

flatulence
cramping

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19
Q

emollients

A

faecal softeners

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20
Q

emollient examples - 4

A

docusate sodium (surfactant and stimulant) suppositories

glycerin suppositories (mildly irritable, inc movement)

groundnut oil, peanut oil

liquid paraffin oral solution

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21
Q

liquid paraffin side effect - 2

A

anal seepage

granulomatosis of GI - which is necrotizing vasculitis

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22
Q

irritant/ stimulant laxatives mechanism of action

A

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)

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23
Q

irritant/ stimulant laxatives/ cathartics examples - 4

A

castor oil

bisacodyl

lubiprostone

anthraquinones

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24
Q

lubiprostone

A

PGE1 derivative that srimulates chloride channels, producing chloride like secretions, helps fecal matter being propelled

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25
anthraquinones examples - 3
plant derivatives senna co-danthramer co-danthrusate
26
co-danthramer co-danthrusate
genotoxic in long term so only given as last resort in terminally ill patients
27
laxative abuse
most common cause of constipation after laxative use, longer interval needed to refill colon post faeces expel, is misinterpreted as constiptation enteral loss of water and salts causes release of aldosterone
28
laxative abuse - release of aldosterone effects
stimulates reabsorption in intestine, but inc renal excretion of K+ ions double loss of K+ ions causes hypokalemia, which thus reduces peristalsis constipation cycle continues
29
diarrhoea cause - 4
toxins microorganisms psychological factors like anxiety antibiotic associated colitis
30
microorganisms that can cause diarrhoea - 5
salmonella e.coli - common in travellers as good at surviving in stomach acid campylobacter clostridium difficile algae
31
____ children die each year due to acute diarrhoea
1-2 million
32
approaches for treating severe acute diarrhoea - 3
maintain fluid/ electrolyte balance use anti infective agents use spasmolytic or other anti diarrhoeal agents
33
anti-diarrheal agents are
anti motility/ spasmolytic agents aka reduce peristalsis by stimulating opioid receptors in bowel allow time for more water to be absorbed by gut firms stool consistency
34
anti-diarrheal agent first line treatment
loperamide hydrochloride or imodium
35
loperamide hydrochloride/ imodium mechanism of action
ant-diarrheal agent first line treatement poor cns penetration inc transit time and sphincter tone antisecretory against cholera toxin and some e. coli toxin
36
loperamide hydrochloride/ imodium side efefcts
overdose, can cause paralytic ileus (muscles of the intestines are temporarily paralyzed, preventing food from passing through) or CNS depression
37
loperamide hydrochloride/ imodium admin and halflife
4mg daily followed by 2 mg doses T1/2 11 hrs
38
other anti diarrheal agents that are less used than loperamide hydrochloride- 4
morphine ( 50 x less potent than first line treatment) codeine dipheoxylate (also an opioid) racecadotril (adjunct to rehydration for uncomplicated acute diarrhoea)
39
clostridium difficile infection
gram positive colonises GI tract major cause of diarrhoea and colitis in patients exposed to antibiotics
40
clostridium difficile infection symptoms - 4
alteration of normal fecal flora colonic colonization of C. difficile growth and production of toxins e.g. toxin a and toxin b, damage lining of colon infection can lead to formation of colitis and toxic megacolon
41
clostridium difficile infection pharmacological treatment - 4
discontinue offending antibiotic for c. difficile: metronidazole (contraindicated in patients with liver or renal impairment) vancomycin (contraindicated in patients with liver or renal impairment) bezlotoxumab
42
antiflatulants
relive painful gas symptoms/ flatulence
43
antiflatulant example
simethicone is a detergent contain gel alters elasticity of mucous coated bubbles, causing them to break in large intestine smaller bubbles = less pain
44
simethicone admin
can be used in babies - no known side effects oral admin
45
there are two types of chronic bowel disease. what are they
irritable bowel disease ibs inflammatory bowel disease ibd
46
irritable bowel syndrome symptoms - 5
nausea diarrhoea/ constipation bloating flatulence abdominal pain/ discomfort
47
irritable bowel syndrome - general info and prevalence
functional GI disorder over >10% prevalence, common oversensitivity of bowel aetiology uncertain but brain-gut link more common in women than men so potentially hormone linked but not menstrual linked so more research needed can present different symptoms
48
ibs treatments - 4
peppermint oil supplement antispasmodic drugs fibre in diet/ supplements antidepressants
49
peppermint oil supplement example in ibs
supplements containing L-menthol relaxes GI smooth muscle by reducing calcium influx
50
antispasmodic drugs example treating ibs
135 mg Mebeverine
51
antidepressants example treating ibs - 2
TCAs SSRIs (but at lower doses than used for depression)
52
inflammatory bowel disease
severe, progressive autoimmune inflammatory disorders long term can be associated with smoking but not always usually people diagnosed before age 40 relatively rare
53
what are the two types of ibd
ulcerative colitis chron's disease
54
ulcerative colitis
diffuse mucosal inflammation that is limited to the colon bloody diarrhea, colicky pain, urgency to peepee
55
chron's disease
inflammatory disease can affect any part of GI tract patchy transmural inflammation abdominal pain diarrhea, weight loss, intestinal obstruction
56
drugs treating ibd - 4
(just symptom management): glucocorticoids to prolong remission and reduce inflammation 5-aminosalicytlates (5-ASAa) immunosuppresant meds (actually may treat): biologics/ monoclonal antibodies
57
non pharma treatments of IBD - 2
surgery to remove parts of bowel fecal transplants to inc microbiota diversity- used following c. difficile infection
58
bezlotoxumab
human monoclonal antitoxin antibody binds to c. difficile toxin b and neutralises its activity prevents recurrance, passive immunity
59
examples of glucocorticoids for ibd treatment - 2
prednisolone budenoside
60
examples of aminosalicylates for ibd treatment - 2
sulfasalazine mesalazine
61
examples of immunosuppressants for ibd treatment
azathrioprine
62
examples of monoclonal antibodies for ibd treatment - 2
infliximab adalimumab
63
prednisolone budenoside
glucocorticoids reduce inflammation short term ibd treatment
64
sulfasalazine mesalazine
aminosalicylates inhibits prostaglandin production ibd treatment
65
azathrioprine
immunosuppressant for severe cases ibd treatment
66
infliximab adalimumab
monoclonal antibodies expensive but good against TNF-alpha ibd treatment
67
what drug can contribute to constipation
morphine can contribute to constipation
68
how do faecal softeners/ emollients work
faecal softeners lubricate stool dec surface tension in intestine, allowing intestinal fluid to penetrate matter usually oil based
69
how do bulk laxatives work
inc in bowel content/ stool bulk volume triggers stretch receptors in intestinal wall, causing peristalsis to propel bowel content forward fibre acts as bulking
70
how do stimulant laxatives work
inc peristalsis
71
laxatives
inc bowel content movement through intestine
72
when should loperamide hydrochloride not be amdinistered
severe abdominal pain/ inflammatory bowel condition
73
what is ulcerative colitis
long-term condition where the colon and rectum (large intestine or large bowel) become inflamed.
74
what is toxic megacolon
rare but life-threatening condition that occurs when the colon becomes inflamed and swollen, often due to a severe infection or colon disease
75
dietary modification can be used to initially treat constipation. example of this?
fiber supplement - psyllium husk inc stool bulk, stimulates peristalsis
76
flatulence meaning
the passing of gas from the intestines through the anus
77
tricycline antidepressant for treating ibs example
amitriptyline - can modulate pain perception so helps
78
shit we gaf - 5
constipation diarrhoea chronic bowel disorder - ibs or ibd c. difficile infection flatulence - gas hurty
79
types of drugs we gaf - 10
purgatives - cons agents that inc motility of GI smooth muscle - cons e.g. laxatives (bulking agents, osmotic, stimulant, faecal softeners) emollients/ faecal softeners - cons antidiarrhoel drugs (dec motility) - dia antispasmodic drugs (dec smooth muscle tone) - dia c. difficile infection antiinfections- dia antiflatulance ibs treatment - peppermint oil supplement, antispasmodic drugs fibre in diet/ supplements ibd - immunosuppresant meds (just symptom management), (actually may treat): biologics/ monoclonal antibodies
80
examples of gaf drugs - 18
bulking agents - agar, bran, ispaghula husk osmotic - milk of magnesium, lactulose, epsom salt stimulant laxative - lubiprostone emollients/ faecal soften - docusate sodium (surfactant and stimulant) suppositories, liquid paraffin oral solution -- anti diarrhoeal - loperamide hydrochloride or imodium discontinue offending antibiotic for c. difficile: metronidazole, vancomycin -- antiflatulence - simethicone -- ibs - antispasmodic Mebeverine, antidepressy ssri -- ibd immunosuppressant - Methotrexate, glucocorticoids like budenoside ibd monoclonal antibody - bezlotoxumab