IBS Flashcards
What is IBS
a chronic GI disorder with abdominal pain and altered bowel habits
What causes IBS
Visceral hypersensitivity altered bowel motility neurotransmitter imbalance infection psychosocial factors
Symptoms of IBS are
abdominal pain distention bloating indigestion various Sx of defecation
What are the 3 subcategories of IBS
Pain with diarrhea
Pain with constipation
Pain with diarrhea and constipation
Patients with IBS can self administer meds to alleviate these Sx
headache sleep disturbance MSK chest pain nausea heartburn back pain
Foundation for treating IBS is
diet and lifestyle modification
Low FODMAP diet (fermentable oligo-, di-, and monosaccharides and polyols)
Exclude foods that increase flatulence, alcohol, and caffeine
Exercise
What foods are in FODMAP
O: wheat, barley, rye, onion, cashew, pistacchio, legumes, chickpeas
D: lactose
M: apple, pear, mango, cherries, asparagus
P: apricots, nectarines, mushrooms
(there are a ton more i didn’t write)
Pharm therapy principle for treating IBS is
Tx directed at relieving abdominal pain and improving bowel function
For diarrhea predominant IBS, initial Tx is
antidiarrheal agent- Loperamide
For constipation predominant IBS, initial Tx is
Fiber to soften stool and reduce straining (but be careful bc increased gas production can exacerbate bloating)
1. Psyllium/ispaghula
if this fails, try Polyethylene glycol
Alternate: Lubiprostone, Linaclotide
What serotonin receptors are in the gut
Type 3 (5-HT3) Type 4 (5-HT4) They are responsible for secretion, sensitization, and motility
What is polyethylene glycol
Osmotic laxative
Improves constipation but NOT abdominal pain
Start w/ 17g powder in 8oz water, titrate up or down. Max 34g
ADE of PEG are
Bloating
Abdominal discomfort
What is Lubiprostone
Prostanoic acid derivative
Stimulates T2 chloride channels in small intestine= increase chloride secretion into sm. int= stimulate intestinal motility and shorten transit time
Good for women 18+ w/ IBS-C, efficacy for men unproven
ADE for Lubiprostone are
Nausea 2/2 delayed gastric emptying
Pregnancy category C, increased fetal loss in guinea pigs
Dose must be reduced if w/ severe hepatic impairment
What is Guanlyate Cyclase-C Agonist Linaclotide (Linzess)
Stimulates intestinal fluid secretion and transit time
Good for those with persistent constipation where PEG didn’t work- improves abdominal pain, bloating, straining, stool consistency, and spontaneous BM x week
290 mcg daily
MC side effect of Linzess is
Diarrhea
What is Tegaserod
5-HT4 agonist that stimulates the release of NT and increases colonic motility
Used only for emergent Tx of IBS with constipation in women <55 y/o
Do we like Tegaserod
No, it was voluntarily removed from the market (except for emergency) 2/2 increased # of CV death
What does Loperamide do
Inhibit peristalsis Prolong transit time Reduce fecal volume Decrease stool frequency and consistency, but does NOT relieve bloating, abd pain, or global IBS Sx Take 2mg 45 min before meal Good for alternating IBS!
What is Eluxadoline (Viberzi)
Mixed mu&kappa-opioid receptor agonist, and delta antagonist
Reduces abdominal pain and diarrhea w/o constipating effects
BUT has abuse potential!
Contraindications to Eluxadoline are
biliary d/o
pancreatitis (esp. severe in those w/o a gallbladder)
severe liver impairment (adjust dose)
heavy alcohol use
MC ADE of Eluxadoline are
nausea, constipation, abdominal pain
pancreatitis in those w/ biliary d/o or alcoholics
CNS depression
What is second line for IBS-D
Bile acid sequestrants (Cholestyramine, colestipol, colesevelam)
