GI Motility 1

Question 1

Drugs stimulating GI motility

• What is the name of the agent that can selectively stimulate gut motor function?

Answer 1

Prokinetic

Question 2

Submucosal IPANs activate the enteric neurons responsible for what 2 activities?

Answer 2

• Peristaltic & Secretory reflex activity

Question 3

Stimulation of 5-HT4 receptors on presynaptic terminals of IPANs enhances release of what 2 substances, therefore promoting reflex activity?

Answer 3

• acetylcholine (ACh)
• Calcitonin gene related peptide (CGRP)

Question 4

What 3 drugs stimulate GI motility?

Answer 4

• Cholinomimetic Agents (cholingergic or anticholinesterase)
• Metoclopramide (dopamine & serotonin antagonist)
• Macrolides (erythromycin antibiotic) motilin receptor

Question 5

What are the 2 Cholinomimetic Agents?

Answer 5

• Bethanechol
• Neostigmine

Question 6

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

Answer 6

Bethanechol

Question 7

Which Cholinomimetic Agent?

• Ach inhibitor
  
  • enhance gastric, small intestine, and colonic emptying

Answer 7

Neostigmine

Question 8

What are the 5 ADEs of Cholinomimetic Agents?

(Drugs stimulating GI motility)

Answer 8

(Cholinergic effects)

1. Excessive salivation
2. Nausea
3. Vomiting
4. Diarrhea
5. Bradycardia

Question 9

4 uses of Cholinomimetic Agents

Answer 9

• GERD
• Impaired gastric emptying
• Non-ulcer Dyspepsia
• Prevention of vomiting

Question 10

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

Answer 10

Cholinomimetic Agents

(Bethanechol & Neostigmine)

Question 11

Which medication is used to tx the following:

Impaired Gastric Emptying

• delayed gastric emptying due to postsurgical disorders (vagotomy, antrectomy)
• diabetic gastroparesis

Answer 11

Cholinomimetic Agents

• Bethanechol
• Neostigmine

Question 12

Which medication is used to tx the following:

• Symptomatic improvement in a small number of patients with chronic dyspepsia

Answer 12

Cholinomimetic Agents

• Bethanechol
• Neostigmine

Question 13

T/F

• Cholinomimetic agents are approved by FDA and available in the US for postpartum lactation stimulation

Answer 13

False

• NOT approved by FDA or available in the US for this purpose

Question 14

Which medication?

• Blocks dopamine D2 receptors in CTZ
• increases esophageal peristalsis
• enhances gastric emptying

Answer 14

Metoclopramide

Question 15

ADEs of Metoclopramide

Answer 15

Extrapyramidal effects:

• dystonia, akathisia,
• Tardive dyskinesia

- elevated prolactin levels: galactorrhea, gynecomastia, impotence, menstrual d/o.

_**avoid long term uses especially in the elderly_

Question 16

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

Answer 16

Erythromycin

(Cholinomimetic Agents - Macrolides)

Question 17

4 medications which cause Constipation

Answer 17

• Opiates
• Calcium Carbonate Antacids
• Diuretics
• Iron preparations

Question 18

Laxatives

• Intermittent constipation is best prevented with what 4 things?

Answer 18

• High fiber diet
• Adequate fluid intake
• Regular exercise
• Pooping when you need to

Question 19

If the patient suffers from constipation due to a secondary cause/disease, what is first line tx?

Answer 19

Treat the underlying cause

Question 20

If a patient suffers from constipation and has no underlying diagnosis, how should you treat? (5)

Answer 20

Choose symptomatic therapy

1. add bulking agents to diet
2. If no relief with bulking agents: add Osmotic laxative (PEG)
3. If no relief with osmotic laxative: add stimulant laxative (Bisacodyl)
4. If none of the above work, use: Lubiprostone or Linaclotide trial
5. Opioid receptor antagonist (if opioid induced)

Question 21

What types of laxatives are these?

• Non-absorbable sugars or salts
• polyethylene glycol

Answer 21

Osmotic Laxatives

Question 22

What are the 2 stimulant laxatives?

Answer 22

Anthraquinone Derivatives (senna, cascara)

Diphenylmethane Derivatives (Bisacodyl)

Question 23

What type of Laxative?

• Lubiprostone

Answer 23

Chloride Channel Activator

Question 24

Which type of laxative?

• Linaclotide
• Plecanatide

Answer 24

Guanylate Cyclase C Agonists

Question 25

What do these agents do? * **Magnesium** citrate * **Magnesium** hydroxide * **Magnesium** sulfate **(high dose)** * Sodium phosphates * Bisacodyl * Polyethylene glycol-electrolyte preparation

Answer 25

Cause **watery evacuation in 1 - 6 hours**

Question 26

Which laxative? * **Indigestible, hydrophilic colloids** that absorb water, forming a **bulky, emollient gel** that distends the colon and promotes peristalsis

Answer 26

**Bulk-Forming Laxatives** | (Psyllium & Methylcellulose)

Question 27

What is the name of the bulk forming laxative made w/ **synthetic fibers**?

Answer 27

**Polycarbophil**

Question 28

What are the 2 names of the common preparations of **bulk forming laxatives which include natural plant products?**

Answer 28

* Psyllium * Methylcellulose

Question 29

**Bulk Forming Laxatives** * Bacterial digestion of plant fibers within the colon may lead to an increase in what 2 sxs?

Answer 29

* bloating * flatus

Question 30

**Which laxative?** * **mixing of aqueous and fatty materials** within the intestinal tract * agent include: **docusate** (oral or enema)

Answer 30

Stool Surfactant Agents (Softeners)

Question 31

**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

Answer 31

**Mineral Oil** | (Stool Surfactant Agents = Softeners)

Question 32

Which laxative? **•CAUTION--aspiration can result in a severe lipid pneumonitis** •long-term use can **i****mpair absorption of fat-soluble vitamins (A, D, E, K)**

Answer 32

**Mineral Oil**

Question 33

What laxative do you use for **acute constipation** or **prevention of chronic constipation?**

Answer 33

Osmotic

Question 34

**Which laxative?** * commonly used osmotic laxative * not be used for prolonged periods in patients with **renal insufficiency due to the risk of hypermagnesemia**

Answer 34

Magnesium Hydroxide - (milk of magnesia)

Question 35

**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**

Answer 35

* **Sorbitol** * **Lactulose**