IBS Flashcards
What is the hallmark symptom of IBS?
abdominal pain relieved by defecation that lasts for a prolonged period of time and also varies over time
What are other symptoms of IBS (not hallmark)?
- diarrhea/ constipation
- fatigue
- bloating
- dyspepsia
What are the proposed mechanisms of IBS?
- altered gut motility
- hypersensitive gut with enhanced visceral perception and pain
- dysregulation of the brain-gut axis
What chemical is the main cause of IBS?
serotonin
What is the diagnosis of IBS?
Recurrent abdominal pain at least 2 days per week over 3 months
PLUS two of the following:
1. pain related by defecation
2. change in frequency of stool
3. change in form of stool
What are the “alarm” / “red flag” symptoms of IBS?
- 50 y/o without colon cancer
- recent change in bowel habit
- evidence of GI bleed
- nocturnal pain/ passage of stool
- unintentional weight loss
- Family hx of colon cancer / IBD
- iron deficiency anemia
- potential drug-induced
What can cause drug-induced diarrhea?
- antibiotics
- caffeine
- colchicine
- Sorbitol-containing products
- laxatives
What can cause drug-induced constipation?
- anticholinergic agents
- aluminum antacids
- opioid analgesics
- anti-diarrheal agents
What drugs can cause abdominal discomfort?
- iron
- corticosteroids
- antibiotics
- bisphosphates
- NSAIDs
What is the only specific diet that has shown efficacy in IBS?
FODMAP
What are non-pharm treatments for IBS?
- soluble fiber / psyllium
- peppermint oil enteric coated capsule
What are psychological therapies for IBS?
- relaxation therapy
- self-administered CBT
- behavioral therapy
- mindfulness meditation
- exercise
What probiotic strain has been shown to improve bloating and flatulence?
bifidobacterium
Do the guidelines recommend probiotics?
No
What is the MOA of antispasmodics?
relaxation of smooth muscle and attenuation of visceral hypersensitivity and pain sensation
When are antispasmodics recommended?
for symptomatic short-term, acute relief of IBS symptoms
What agents does Donnatol contain?
Hyoscyamine, atropine, phenobarbital, scopolamine
What agents are used for antispasmodics in IBS?
Dicyclomine
Hyoscyamine
Donnatol
What antispasmodic is the DOC in Canada?
Scopolamine
What are SEs with antispasmodics?
anticholinergic- drowsiness, heat intolerance, constipation
When are TCAs used in IBS?
sub-depression doses are effective in relieving visceral pain and improving symptom relief
What TCAs are used in IBS?
Amitriptyline
Doxepin
Desipramine
What TCA is best at treating pain?
Amitriptyline
What TCA is good for pain and improves incomplete evacuation?
Doxepin
What antibiotic is recommended for IBS-D?
Rifaximin
What is the MOA of Rifaximin?
inhibition of bacterial RNA synthesis
What is the daily dosing of Rifaximin for IBS?
TID
What are ADEs with Rifaximin?
- peripheral edema
- dizziness
- nausea
- headache
What agent is approved for women with severe IBS-D unresponsive to conventional therapy?
Alosetron
What is the MOA of Alosetron (LOTRONEX)?
5-HT3 antagonist
What should Alosetron therapy be held and can be restarted at lower dose?
Constipation
When should Alosetron therapy be discontinued and NOT restarted?
Ischemic colitis
What dose of Alosetron requires a REMS program for ischemic colitis?
1mg BID
What is the MOA of eluxadoline?
Mixed opioid receptor modulator
( mu and kappa agonist)
(Delta antagonist)
What patient population is eluxadoline approved for?
Adults with IBS-D
What are contraindications to Eluxadoline?
- No gallbladder
- Alcoholism or history of
- History of pancreatitis
- Severe hepatic impairment
What drugs interact with Eluxadoline?
Dose -dependent OAT inhibitors:
Cyclosporine
Genfibrozil
Rifampin
When should the dose of Eluxadoline be reduced?
- Unable to tolerate 100mg
- Drug interactions
- Mild /moderate hepatic dysfunction
What warnings should be considered when taking Eluxadoline?
Severe constipation
Development of pancreatitis
What is the mechanism of Linaclotide?
Agonist of guanylate cyclase C;
Increases secretion of chloride and bicarbonate into the intestinal lumen to make an osmotic gradient
What ADRs are associated with linaclotide (LINZESS)?
severe diarrhea (within first 2 weeks)
GI bleed
What is the MOA of Plecanatide?
Structural analog of human uroguanylin;
change in the pH of the intestines leading to increased fluid secretion fluid secretion and decreased pain sensation
What are the ADRs with Plecanatide (TRULANCE)?
- dyspnea
- nausea
- severe diarrhea
How is Plecanatide dispensed because it is unstable in air and to improve compliance?
blister pack;
do not dispense in vials
What agent is approved for women >/= 18 years with IBS-C?
Lubiprostone (AMITIZA)
What other indications does Lubiprostone (AMITIZA) have?
- chronic idiopathic
- opioid-induced constipation
What are ADRs with Lubiprostone?
- dyspnea
- nausea
- severe diarrhea
How long does it take for Lubiprostone to start working?
2 months
What is the MOA of Tegaserod (ZELNORM)?
5HT4 agonist
What population is Tegaserod approved in for IBS-C?
Women >/= 18 y/o and < 65 y/o with IBS-C
What are ADRs with Tegaserod (ZELNORM)?
Cardiovascular events (MI, TIA)
Severe diarrhea
suicidal ideation and behavior
What are the contraindications to Tegaserod?
Cardiovascular risk factors:
1. active smoking
2. BMI>30
3. HTN, DM, hyperlipidemia
4. any previous cardiovascular event
5. history of ischemic colitis
6. eGFR< 15
7. childs pugh B or C
8. history of gallbladder disease
What patient population is Tenapanor approved in?
IBS-C in adults
What is the MOA of Tenapanor?
sodium/hydrogen exchange isoform 3 (NHE3)
What are the contraindications to Tenapanor?
- obstruction
- patients under 6 y/o
What are ADRs to Tenapanor?
Diarrhea
Flatulence
Dizziness
What OTC is used for diarrhea but has insufficient evidence to recommend for IBS-D?
Loperamide
What OTC agent is used but has no evidence for improvement in symptoms or pain?
Polyethylene glycol
What are ADRs with Polyethylene glycol?
- bloating
- abdominal discomfort
