IBS Flashcards
define IBS
recurren abdominal pain or discomfort at least 3 days per month in last 3 months associated with:
improvement with defacation, onset associated with a change in stool frequency and appearance
subtypes of IBS based on the predominant stool pattern
with constipation
with diarrhea
mixed
unsubtypes
IBS pathophys
nervous system(brain gut interactions)
gut flora issues (post infection, bacterial overgrowth)
altered sensitivity to gut distention altered signal processes in the cns
altered motor response
alarm features
weight loss >5kg bloody stool severe diarhea recurring fever over 50 (rare for onset to be in elderly) family histoyr of colon cancer and IBD
what quides therapeutic plans
predominant symptoms
constipation, diarrhea, pain, bloating, gas
sources of constipation to look for
low fibre, lack of exercise, meds, decreased abdominal pressure, metabolic abnormalities
sources of diarrhea to look for
food
lactose
sorbitol
fructose
non pharms
establish therapeutic relationship with patient
regulate dietary intake
avoid precipitants
avoid excess - carbonated drinks, gum, caffiene
behavioural therapies
relax biofeedback hypnotherpay CBT psychotherapyu
how long does i take to assess efficacy of treatment
3-4 weeks
treatment for IBS with constipation
fiber based products osmotic and salt laxatives stimulant laxatives prucalopride linaclotide
fibre based products MOA
increase stool bulk and frequency
increase GI transit time
reduce gas by binding bile salts
benefit of fiber based products
not much better than placebo
best in abdominal pain and constipation
how to initiate psyllium
1tsp per day and increase 3-5 days
up ro 1-2 tsp 3 times a day or more
examples of osmotic and salt laxatives
lactulose (AE:gas, bloating, taste)
magnesium
phosphate
PEG based
describe stimulant laxatives
senna based , bisacodyl
quick onset
AE: cramping
dont cause colon dysfunction
how to approach laxatives
start with regimen as a regular routine then change from there
prucalopride MOA
serotonin 4 receptor agonist
lower affinity for hERG
stimulates colonic transit
prucalopride indication
chronic idiopathic constipation in females with inadequate response to laxatives
prucalopride disadvantage
renally cleared
not for pregnancy
nausea diarrhea, headache dose related
not covered
linaclotide MOA
peptide guanylate cyclse C agonist
indirectly activates cystic fibrosis transmembrane conductance regulator
secretion of CI and bicarb into bowel and increased transit
linaclotide disadvantage
diarrhea
not approved for plan coverage
treatment steps for IBS with constipation
bran or psyllium — osmotic laxative magnesium —stimulant senna —- add on with lactulose or PEG — linaclotide or prucalopride for refractory
treatments for IBS with diarrhea
loperamide cholestyramine alosetron fiber eluxadoline rifaximin
loperamide use
can be used prophylactically
bloating may be worsened and ab pain may develop
describe cholestyramine use
3rd line role
can be used as add on
AE: taste and drug interactions
eluxadoline MOA
mu opioid agonist and delta opioid receptor antagonist
min absorbtion - acts locally
describe alosetron
serotonin 3 receptor antagonist
better than placebo, improves overall symptoms
major concerns with ischemic colitis lead to withdrawal, can get via approval process
dose of fiber to increase stool consistency
30g/day but start lower and gradually increase
problems with ibs studies
being able to compare the patient populations between studies
lack of reproduceability
much less high quality studies than other GI topics
results of studies of obs therapies often were
short term response over a few weeks
very high placebo response rate
who should be considered for drug therapy
wehn IBS symptoms are impacting quality of life
fibre based products AE
bloating in high doses
increase gas produced in the intestines
linaclotide efficacy
modest beneficial effect in ab pain and complete bowel movements
loperamide MOA
increase transit time, water and electrolyte absorption and increase anal sphincter tone
loperamide efficacy
improve stool consistency and ab pain over placebo
lack in decreased global symptoms and other important outcomes
approach to treating ibs with diarrhea
exclude lacctose intolerance and celiac
anti diarrheals first line - loperamide
add in fiber slowly to increase stool consistency
possible treatment for IBS with bloating and gas
not likely to get beenfit from drugs diet fiber antidepressants, antispasmodics, go for a walk after meals
antispasmotic MOA
decrease pontaneous smooth muscle stimulated movements - anticholinergic or antiuscarinic
use of antispasmodics
may provide relief of ab pain, distention, bloating
generally no better than placebo, odd patient swears it works
antispasmodic AE
anticholinergic
tolerance
examples of antispasmodics
belladona
hyoscyamine
dicyclomine
treatment for IBS pain
behaviour and aversion techniques
antidepressants and nsaids for refractory
narcotics not successful
antidepressant efficacy
increase pain threshold
no improvement with SSRI, modest relief with TCA
antidepressant doses
chronic pain loses (low)
antibiotic use in IBS
help and worsen IBS
bacterial overgrowth
probiotics MOA
competition with pathogenic bacteria
antiinflammatory
problem with probiotics
dont really know which ones to use and which dose
gut floral in IBS patients
tend to be altered
instable
problems with probiotics
GI flora anaerobic so hard to capture and grow
the bacteria are cleared from teh GI tract within a week
problems with probiotic studies
small studies
no clear specific endpoint target
inter individucal variability in commensal flora
significant placebo response in trials
what is VSL3
a probiotic
how long do you have to be on probiotics for
indefinately because they are cleared within a week
