tx for diarrhea/constipation/ab pain

Question 1

drugs for diarrhea

Answer 1

PG inhibitors (bismuth)
Opioid agonists
5-HT3 antagonists
Cl channel inhibitors

Question 2

Loperamide

Answer 2

opioid agonist
no analgesic effect, no addiction
slows peristalsis
anticholinergic side effects (urinary retention)

Question 3

diphenoxylate

Answer 3

opioid agonist
atropine added to discourage abuse
inhibits GI motility
anticholinergic side effects (more so due to atropine)

Question 4

eluxadoline

Answer 4

opioid agonist
mu and kappa receptor agonist
slow peristalsis
antagonist at delta, decreasing GI secretions
indicated for IBS-D
Side effects:
- hepatic/pancreatic toxicity
- pancreatitis high risk w/o gallbladder
contraindicated in pts with biliary tree disease or hepatic impariment

Question 5

alosetron

Answer 5

5-HT3 antagonist
indicated for IBS-D in women unresponsive to other tx
side effect includes ischemic colitis

Question 6

crofelemer

Answer 6

from a tree
blocks CFTR and calcium activated chloride channel
treats diarrhea in HIV pts on antiretroviral therapy
side effects include URI

Question 7

agents for abdominal pain in IBS

Answer 7

antimuscarinic agents

• hyoscyamine
• dicyclomine
• clidinium
• chlordiazepoxide

Question 8

agents for constipation

Answer 8

laxative/cathartic agents
Opioid antagonists
guanylate cyclase agonists
selective chloride channel activators

Question 9

linaclotide

Answer 9

GC-C agonist
increases cGMP conc
stimulates Cl secretion and intraluminal fluid flow
indicated for IBS-C and chronic constipation

Question 10

lubiprostone

Answer 10

PGE1 derivative
increases fluid secretion by activating chloride channel
indicated for IBS-C in women, chronic and opioid induced constipation (non-cancer adults)

Question 11

methylnaltrexone and naloxegol

Answer 11

mu antagonist

indicated in OIC

Question 12

Classifications of laxatives and cathartics

Answer 12

Stimulants
osmotics
salines
bulk forming
stool softeners

Question 13

bulk forming agents

Answer 13

fiber/bran
psyllium
methylcellulose/carboxymethylcellulose
calcium polycarophil 
lots of drug interactions with psyllium and celluloses

Question 14

stool softeners

Answer 14

surfactant or emollient laxatives
Docusate salts
mineral oil
minimal laxative effect

Question 15

stimulants (irritants)

Answer 15

senna
bisacodyl
castor oil
glycerin
sodium picosulfate 
stimulate peristalsis 
fluid/electrolyte disturbance can occur with long use
contraindicated in GI obstructions/ilius, several agents can pass into breast milk

Question 16

Saline agents

Answer 16

magnesium salts (milk of magnesia)
sodium phosphate (osmoprep)
hyperosmolar solutions that are poorly absorbed 
drug interactions with diuretics and use caution with renal disease, CHF/HTN

Question 17

Osmotic agents

Answer 17

lactulose (treats hyperammonemia by changing pH and trapping NH4+)
magnesium citrate
sorbitol
Polyethylene glycol (PEG-3350) (bowel prep prior to scope) (smaller dose is MiraLax)