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Pharmacology Unit 6 > Gastrointestinal Drugs II > Flashcards

Flashcards in Gastrointestinal Drugs II Deck (43)
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1


Causes of gastroesophageal reflux

 

  • Lower esophageal sphincter - inappropriate relaxation, low resting tone, anatomical alteration
  • Acid hypersecretion
  • Decreased acid clearance due to impaired peristalsis or abnormal saliva production
  • Delayed gastric emptying and/or duodenogastric reflux of bilee salts and pancreatic enzymes

2


GERD lifestyle Tx

 

  • Elevate head of bed
  • Avoid food/liquid 2-3 hrs before bedtime
  • Avoidance of fatty or spicy food
  • Avoidance of cigs/alcohol
  • Weight loss
  • Liquid antacid
  • Pregnancy

3


Tx of GERD in patients w/o Esophagitis

 

  • Alginic acid antacids
  • Promotility drugs - cisapride, metoclopramide
  • H2 blockers - cimetidine, ranitidine, famotidine, nizatidine

4


Tx of GERD of patients w/ esophagitis

 

  • H2 blockers
  • OR
  • H2 recceptor blockers + promotility agent
  • OR
  • PPI
  • OR
  • Anti-reflux surgery

5


MOA of promotility drugs to treat GERD?


Promotility drugs prevent acid from sitting in stomach too long

6


What are the promotility drugs?


Metochlopramide, cisapride

7


SE of promotility drugs?


Tremor

8


What is vomiting mediated by?


Chemoreceptor Trigger Zone and Vomiting Center in the Medulla

9


What is vomiting stimulated by?


Local irritation or CNS stimulation

10

Metabolic consequences of vomiting?

 

  • Dehydration
  • Hypochloremic metabolic alkalosis
  • Hypokalemia (Kidney reuptake of acid results in K+ loss)

11

What are the classes of antiemetics?

 

  • Phenothiazines
  • Benzamide
  • Tetrahydrocannabinol
  • Serotonin (5HT3) receptor antagonists

12

What are the phenothiazines?


The neuroleptic class

  • Prochlorperazine
  • Promethazine

13


MOA of Phenothiazine? Promethazine?

 

  • Prochlorperazine - Dopaminergic receptor antagonist
  • Promethazine - H1 anticholinergic

14


SE of prochlorazine and promethazine?

 

  1. Prochlorperazine - Torticollis
  2. Promethazine - Somnolence

15


Adverse effects of Benzamide derivatives?


Extrapyramidal Syx (but ont as severe phenothiazines)

16


What are the Benzamide derivatives?

 

  • Trimethobenzamide
  • Metochlopramide

17

MOA of Trimethobenzamide and Metochlopramide?

 

  • Trimethobenzamide - unknown effects on CRTZ
  • Metochlopramide - CNS and peripheral dopaminergic receptor antagonism

18


MOA of THC?


Suppress the CRTZ by probable anticholinergic mechanism

19


What are the 5HT3 blockers?


Ondansetron, Granesitron, Dolasetron

20

Adverse SE of 5HT3 antagonists?


Headache, dizziness, somnolence

21


Tx strategy for gastroparesis?

Metochlopramide, cisapride, domperidone

22


5 Types of diarrhea?

 

  1. Secretory - Na and Cl secretion/decreased reabs
  2. Osmotic - Nonabs molecules in gut lumen
  3. Inflammatory absorptive surface - Destruction of mucosa, impaired abs, outpouring of blood, mucus
  4. Decreased abs - impaired reabs of electrolytes
  5. Motility disorder - Increased motility/decreasd motility with bacterial growth

23

What are the goals to treat diarrhea?


Decrease GI secretion and decrease GI motility

24


What are the classes for diarrhea Tx?

 

  • Anticholinergics
  • Opioid Agonists
  • Colloids
  • Pectins

25

Anticholinergic drugs to treat diarrhea?


Atropine sulfate

26


MOA of loperamide?


Immodium! increase rectal tone and disrupt peristalsis via mu receptor

27


MOA of diphenoxylate and codeine sulfate?


Mu-R agonist causing contraction of circular muscle "segmentation"

28


What are the colloids and pectins and what is their MOA?

 

  • Colloid - Metamucil
  • Pectin - Kaopectate

Bulk up stool

29


What is the treatment for constipation?


Laxatives or cathartics

30

What are the classes of treatments for constipation?

 

  • Irritants/Stimulants
  • Osmotic cathartics
  • Bluk-forming (hydrophilic colloids)
  • Lubricants and fecal softeners