Lower GI Pharmacology Flashcards

1
Q

Best anti-diarrheal agent
Poorly penetrates the CNS
u receptor agonist

A

Loperamide (Imodium)

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2
Q

Anti-diarrheal agonist

Can produce CNS effects – abuse potential given with atropine

A

Diphenoxylate (Lomotil)

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3
Q

Absorbs water and increases stool bulk

A

Bulk forming and absorbents: Kaolin (clay) + pectin (Kaopectate); also fiber

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4
Q

Includes bismuth which is thought to have anti-secretory, anti-inflammatory and anti-microbial effects
Use to prevent and treat traveler’s diarrhea

A

Bismuth subsalicylate (pepto bismol)

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5
Q

Somatostatin analog; inhibits secretory diarrhea d/t hormone-secreting tumors of the pancreas and GI tract

A

Octreotide (Sandostatin)

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6
Q

Off-label uses for Octreotide

A

Post operative dumping syndrome, variceal bleeding, other forms of diarrhea

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7
Q

3 mechanims laxatives work by

A
  1. enhancing the retention of intraluminal fluid by hydrophilic or osmotic mechanisms
  2. decreasing net absorption or increase secretion of fluid by effects on small- and large-bowel fluid and electrolyte transport
  3. altering motility
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8
Q

Mechanism of dietary fiber

A

Fiber fermented by the colon bacteria produces short chain fatty acids which are somewhat prokinetic and trophic for the endothelium
Fermentation increases stool bacterial mass

**Non-fermented fiber retains water and increases stool bulk

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9
Q

Inorganic salts that are not absorbed causes water retention
Bowel cleansing products

A

Milk of Magnesia (MgOH2)

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10
Q

Osmotic laxative

Unabsorbed carbohydrate metabolized to short chain fatty acids by gut bacteria

A

Lactulose

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11
Q

Another use of Lactulose

A

Portal-systemic encephalopathy – can decrease ammonia levels

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12
Q

Not absorbed, remains in the lumen
Retain water due to osmotic grade
May be given with isotonic Na and K salts (prevent net ionic shift)

A

Polyethylene Glycol (PEG, Miralax)

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13
Q

Anionic surfactant, lowers surface tension

A

Ducosate salts (bilax, colace)

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14
Q

Stimulant laxatives

Cause mucosa inflammation/irritation

A

Contact cathartics

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15
Q

Laxative
Diphenylmethane, Prodrug - converted by bowel esterases
Acts on large intestine

A

Bisacodyl

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16
Q

Laxative
Anthraquinone cathartics, Prodrug - requires colonic bacteria
Plant derivative
Acts on large intestine

A

Senna

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17
Q

Prostanoid
Activates chloride channels in the intestine to increase fluid secretion
Not absorbed and only acts in intestinal lumen
Used for adult chronic constipation and women with IBS

A

Lubiprostone

18
Q

Binds and activates guanylate cyclase C receptor on the luminal surface of intestinal epithelial cells to increase intracellular and extracellular cGMP –> chloride and bicarb secretion, extracellular cGMP may decrease visceral pain

Used for chronic idiopathic constipation, irritable bowel syndrome with constipation

A

Linaclotide

19
Q

Opioid receptor antagonist

For constipation

A

Methylnaltrexone

20
Q

5HT3 receptor antagonist used for diarrhea dominant irritable bowel syndrome (restricted use)

A

Alosetron

*Concern with increased incidence of ischemic colitis with use

21
Q

Therapeutic goals of IBD

A
  1. Treat acute attacks
  2. Maintain remission - long term management
  3. Treat complications
22
Q

Used for mod-severe acute attacks

Disadvantage – systemic affects

A

Prednisone

23
Q

Enteric release steroid used for Crohn’s disease to target the inflamed gut –> less side effects

A

Budesonide

24
Q

5-aminosalicylate
Delayed time or pH dependent release
For mild to moderate UC (less effective for Crohn’s)

A

Mesalamine

25
Q

5-aminosalicylate

Prodrugs – converted to Mesalamine

A

Olsalazine

Sulfasalazine

26
Q

SE of Sulfasalazine

A

Related to sulfapyridine and include fever, malaise, vomiting, headache

27
Q

SE of Mesalamine

A

Relatively infrequent and minor and include headache, dyspepsia, and skin rash

28
Q

SE of Olsalazine

A

Diarrhea

29
Q

Which patients should you avoid 5-aminosalicylates in?

A

Contraindicated in patients allergic to salicylate

30
Q

Thiopurine antimetabolites for IBD

A

6-mercaptopurine

Azathioprine

31
Q

What is azathioprine metabolized to?

A

6-mercaptopurine

32
Q

SE of Azathioprine?

A

Numerous, bone marrow suppression, vomiting, jaundice, pancreatitis
Used for both UC and Crohn’s

33
Q

Dihydrofolate reductase inhibitor, off label use for Crohn’s

A

Methotrexate

34
Q

Calcineurin inhibitor off label use for ulcerative colitis

A

Cyclosporine

35
Q

Immunoglobulin against TNFalpha

Used for moderate to severe Crohn’s and UC

A

Infliximab

36
Q

SE of Infliximab

A

Lupus-like syndrome, delayed hypersensitivity, infection

Increased URI and increased incidence of non-Hodgkin lymphoma

37
Q

Recombinant human IgG1 monoclonal antibody against TNFalpha

Used for IBD

A

Adalimumab (Humira)

38
Q

A pegylated humanized antibody Fab fragment of TNFalpha monoclonal antibody
Used for IBD

A

Certolizumab pegol (Cimzia)

39
Q

Monoclonal antibody against 4-integrin

Binds 4-integrin and reduces leukocyte extravasation

A

Natalizumab (Tysabri)

40
Q

Why isn’t Natalizumab used very often?

A

Increases the risk of progressive multifocal leukoencephalopathy (PML)