GI Motility 1 Flashcards
Drugs stimulating GI motility
- What is the name of the agent that can selectively stimulate gut motor function?
Prokinetic
Submucosal IPANs activate the enteric neurons responsible for what 2 activities?
- Peristaltic & Secretory reflex activity
Stimulation of 5-HT4 receptors on presynaptic terminals of IPANs enhances release of what 2 substances, therefore promoting reflex activity?
- acetylcholine (ACh)
- Calcitonin gene related peptide (CGRP)
What 3 drugs stimulate GI motility?
- Cholinomimetic Agents (cholingergic or anticholinesterase)
- Metoclopramide (dopamine & serotonin antagonist)
- Macrolides (erythromycin antibiotic) motilin receptor
What are the 2 Cholinomimetic Agents?
- Bethanechol
- Neostigmine
Which Cholinomimetic Agent?
- Stimulates muscarinic M3 receptors on muscle cells and at myenteric plexus synapses
- History of use in the treatment of GERD and gastroparesis
Bethanechol
Which Cholinomimetic Agent?
-
Ach inhibitor
- enhance gastric, small intestine, and colonic emptying
Neostigmine
What are the 5 ADEs of Cholinomimetic Agents?
(Drugs stimulating GI motility)
(Cholinergic effects)
- Excessive salivation
- Nausea
- Vomiting
- Diarrhea
- Bradycardia
4 uses of Cholinomimetic Agents
- GERD
- Impaired gastric emptying
- Non-ulcer Dyspepsia
- Prevention of vomiting
Which medication is used to tx the following:
- treatment of symptomatic GERD
- not effective in patients with erosive esophagitis
- use prokinetic agents + antisecretory agents in pts with regurgitation or refractory heartburn
Cholinomimetic Agents
(Bethanechol & Neostigmine)
Which medication is used to tx the following:
Impaired Gastric Emptying
- delayed gastric emptying due to postsurgical disorders (vagotomy, antrectomy)
- diabetic gastroparesis
Cholinomimetic Agents
- Bethanechol
- Neostigmine
Which medication is used to tx the following:
- Symptomatic improvement in a small number of patients with chronic dyspepsia
Cholinomimetic Agents
- Bethanechol
- Neostigmine
T/F
- Cholinomimetic agents are approved by FDA and available in the US for postpartum lactation stimulation
False
- NOT approved by FDA or available in the US for this purpose
Which medication?
- Blocks dopamine D2 receptors in CTZ
- increases esophageal peristalsis
- enhances gastric emptying
Metoclopramide
ADEs of Metoclopramide
Extrapyramidal effects:
- dystonia, akathisia,
- Tardive dyskinesia
- elevated prolactin levels: galactorrhea, gynecomastia, impotence, menstrual d/o.
_**avoid long term uses especially in the elderly_
Which drug?
- Directly stimulate motilin receptors on GI smooth muscle
- Tolerance rapidly develops
- Used in patients with acute upper gastrointestinal hemorrhage to promote gastric emptying of blood before endoscopy
Erythromycin
(Cholinomimetic Agents - Macrolides)
4 medications which cause Constipation
- Opiates
- Calcium Carbonate Antacids
- Diuretics
- Iron preparations
Laxatives
- Intermittent constipation is best prevented with what 4 things?
- High fiber diet
- Adequate fluid intake
- Regular exercise
- Pooping when you need to
If the patient suffers from constipation due to a secondary cause/disease, what is first line tx?
Treat the underlying cause
If a patient suffers from constipation and has no underlying diagnosis, how should you treat? (5)
Choose symptomatic therapy
- add bulking agents to diet
- If no relief with bulking agents: add Osmotic laxative (PEG)
- If no relief with osmotic laxative: add stimulant laxative (Bisacodyl)
- If none of the above work, use: Lubiprostone or Linaclotide trial
- Opioid receptor antagonist (if opioid induced)
What types of laxatives are these?
- Non-absorbable sugars or salts
- polyethylene glycol
Osmotic Laxatives
What are the 2 stimulant laxatives?
Anthraquinone Derivatives (senna, cascara)
Diphenylmethane Derivatives (Bisacodyl)
What type of Laxative?
- Lubiprostone
Chloride Channel Activator
Which type of laxative?
- Linaclotide
- Plecanatide
Guanylate Cyclase C Agonists
What do these agents do?
- Magnesium citrate
- Magnesium hydroxide
- Magnesium sulfate (high dose)
- Sodium phosphates
- Bisacodyl
- Polyethylene glycol-electrolyte preparation
Cause watery evacuation in 1 - 6 hours
Which laxative?
- Indigestible, hydrophilic colloids that absorb water, forming a bulky, emollient gel that distends the colon and promotes peristalsis
Bulk-Forming Laxatives
(Psyllium & Methylcellulose)
What is the name of the bulk forming laxative made w/ synthetic fibers?
Polycarbophil
What are the 2 names of the common preparations of bulk forming laxatives which include natural plant products?
- Psyllium
- Methylcellulose
Bulk Forming Laxatives
- Bacterial digestion of plant fibers within the colon may lead to an increase in what 2 sxs?
- bloating
- flatus
Which laxative?
- mixing of aqueous and fatty materials within the intestinal tract
- agent include: docusate (oral or enema)
Stool Surfactant Agents (Softeners)
Which laxative?
- clear, viscous oil that lubricates fecal material, retarding water absorption from the stool
- used to prevent and treat fecal impaction in young children and debilitated adults
Mineral Oil
(Stool Surfactant Agents = Softeners)
Which laxative?
•CAUTION–aspiration can result in a severe lipid pneumonitis
•long-term use can impair absorption of fat-soluble vitamins (A, D, E, K)
Mineral Oil
What laxative do you use for acute constipation or prevention of chronic constipation?
Osmotic
Which laxative?
- commonly used osmotic laxative
- not be used for prolonged periods in patients with renal insufficiency due to the risk of hypermagnesemia
Magnesium Hydroxide - (milk of magnesia)
Which 2 laxatives?
- nonabsorbable sugars that can be used to prevent or treat chronic constipation
- sugars are metabolized by colonic bacteria, producing severe flatus and cramps
- Sorbitol
- Lactulose
