Flashcards in Motility Disorders Deck (37):
What are prokinetic agents?
Drugs that selectively stimulate gut motor fxn
What is the action of intrinsic primary afferent neurons (IPANs)?
Activate enteric neurons responsible for peristalsis & secretory reflex
What action enhances the release of Ach & calcitoningene-related peptide, promoting reflex activity?
Stimulation of 5-HT4 receptors on presynaptic terminals of IPANs
What are cholinomimetic agents used for?
Impaired gastric emptying
Prevention of vomiting
What cholinoimetic agent is NOT approved by FDA or available in the US?
Domperidone (pospartum lactation stimulation)
What are ADEs of metoclopramide?
What is the MOA of erythromycin (a macrolide)?
Stimulate motilin receptors
How do you treat a patient w/ constipation who has no underlying dx?
List the laxative agents (8)
Stool surfactant (softeners)
Chloride channel activator
Guanylate cyclase c activator
Opioid receptor antagonists
Serotonin 5-HT4 agonists
What 3 agents result in soft or semifluid stool in 6-12 hrs?
Mg sulfate (low dose)
What 6 agents cause watery evacuation in 1-6 hrs?
Mg sulfate (high dose)
What are 2 common preparations of bulk forming laxatives?
Natural plant products:
What is an example of a stool surfactant agent?
Docusate (oral or enema)
What can mineral oil cause?
Aspiration --> severe lipid pneumonitis
What are examples of osmotic laxatives?
Mg hydroxide (Milk of Mag)
Sorbitol & lactulose
What is the MOA of stimulant laxatives?
Direct stimulation of the enteric NS
Cathartics may be required on a _______
What are examples of stimulant laxatives?
Anthraquinone derivatives: aloe, senna, cascara
What are characteristics of bisacodyl (a diphenylmethane derivative)?
Minimal systemic absorption
Appears to be safe for acute & long-term use
What are 3 examples of opioid receptor antagonists?
What are clinical controversies?
1. Withholding food is considered inappropriate in pts w/ no signs of severe dehydration
2. In osmotic diarrhea, food may control the problem
3. If the mechanism is secretory, diarrhea persists
What are examples of antidiarrheal agents?
Bile salt-binding resins (cholestyramine, colestipol, colesevelam)
Colesevelam does not appear to have significant effects on...
absorption of other drugs
14-amino-acid peptide released in the GI tract & pancreas from paracrine cells, D cells, enteric nerves, & the hypothalamus
What is the MOA of somatostatin?
Inhibits the secretion of numerous hormones & transmitters
Reduces intestinal fluid secretion & pancreatic secretion
Slows GI motility & inhibits gallbladder contraction
What do GI neuroendocrine tumors cause?
What inhibits this?
What are ADEs of octreotide?
Nausea, abd pain, flatulence, diarrhea
Prolonged tx --> hypothyroidism
What is the MOA of metoclopramide?
D2 receptor antagonist
Blocks D2 receptors in the trigger zone of the medulla
What is the action of metaclopramide?
- esophageal peristalsis
- LES pressure
- gastric emptying
What is the MOA of bethanechol (a cholinomimetic)?
Stimulates M3 receptors at myenteric plexus synapses
What is the MOA of neostigmine (a cholinoimetic)?
What are ADEs of cholinomimetics?
Salivation, N/V/D, brady
Which types of laxative cause softening of feces in 1-3 days?
What are 2 examples of purgatives (laxatives)?
Mg citrate & Na phosphate
What are ADEs of anthraquinone derivatives: aloe, senna, & cascara?
Concern that these agents may be carcinogenic, but studies do not suggest relation
What is alvimopan (an opioid receptor antagonist) used for?
shortens the period of postop ileus in hospitalized pts who undergo small or large bowel resection