E2: GI Drugz Flashcards

1
Q

MOA for antacids

A

Inorganic bases that neutralize HCl to form salt and H2O

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2
Q

List the 2 drugs in the Antacids class

A

Magnesium Hydroxide

Aluminum Hydroxide

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3
Q

What is the primary adverse effect of Magnesium Hydroxide? Aluminum Hydroxide? How can this be improved?

A
Mg = diarrhea
Al = constipation

Combine together to cancel out these effects

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4
Q

What are the uses of Antacids?

A

Symptomatic short term relief of heartburn and GERD (or used as adjunct therapy)

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5
Q

Antacids are contraindicated in what pt population?

A

Patients w/ kidney dysfunction (can cause accumulation of toxins)

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6
Q

Antacids have a high potential for _____.

A

Drug interactions

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7
Q

Name the 2 drugs in the H2 blockers class.

A

Cimetidine

Ranitidine (Zantac)

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8
Q

MOA for H2 blockers

A

COMPETITIVE antagonists of H2

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9
Q

When are H2 blockers most effective? When should you educate your patients to take them?

A

Most effective at decreasing nocturnal acid formation

Pts should take at bedtime!

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10
Q

What are 4 uses of H2 blockers?

A
  • Duodenal and gastric ulcers*
  • Given w/ H1 antagonists for severe allergic rxn (decrease vasodilation)*
  • Adjuncts for GERD and ZES
  • Given pre-operatively in case of aspiration

*Most important

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11
Q

H2 blockers are metabolized by the _____ and excreted by the _____.

A

Metabolized by liver

Excreted by kidney

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12
Q

What are 3 general adverse effects of H2 blockers? What is a specific adverse effect for Cimetidine and in what how can this be used therapeutically?

A
  • HA
  • Nausea
  • Confusion (elderly)

Chronic cemetidine: Anti-androgenic effects (ex: gynecomastia) - used to tx HIRSUITISM in females

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13
Q

Which H2 blocker can cause drug interactions? What liver enzyme does this drug inhibit?

A

Cimetidine inhibits CYP3A4

*Drug interactions with phenytoin, warfarin, theophylline, benzos, TCAs, etc.

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14
Q

Name the 2 PPIs

A

Omeprazole

Esomeprazole

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15
Q

MOA for PPIs

A

IRREVERSIBLY inhibit the proton pump in the final stage of gastric acid production (binds to H/K pump)

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16
Q

What is the DOC for GERD w/ esophagitis?

A

PPIs - extremely effective!

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17
Q

In what form are PPIs ingested into the body?

A

Ingested as prodrugs –> must be converted to active sulfenamide

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18
Q

How long does it take for the PPIs (Omeprazole, Esomeprazole) to start working? How long do their effects last once discontinued?

A

2-5 days to start working

Effects last 24-48 hrs upon discontinuation

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19
Q

Though usually minimal, what are the adverse effects of PPIs? (6)

A
  • Nausea/Diarrhea/Abd. colic
  • Increased URIs (specifically pneumonia)

Chronic use:

  • Decreased Ca absorption (risk for osteoporosis)
  • Hypomagnesia
  • Vit B12 deficiency
  • Increased risk of CKD
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20
Q

What liver enzyme does Omeprazole inhibit? This effects the metabolism of what 3 other drugs?

A

Inhibits CYP249

Decreased metabolism of phenytoin, diazepam, and warfarin

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21
Q

What drug is a Cytoprotective Agent? What is the MOA?

A

Misoprostol

MOA: Prostaglandin E1 analogue (increased secretion of mucous, decreased acid secretion)

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22
Q

What is the primary use of Misoprostol (cytoprotective agent)?

A

Prevention of NSAID-induced uclers

23
Q

What drug can be used for prevention of NSAID-induced ulcers?

A

Misoprostol

24
Q

What is the primary effect of the prokinetic agents? What 3 drugs fall under this class?

A

Increase GI activity

  • Metoclopramide
  • Bethanechol
  • Erythromycin
25
Q

What 2 drugs are used to tx post-surgical gastric hypomotility? Which drug is also an antiemetic?

A

Metoclopramide (hypomotility + antiemetic)

Bethanechol (hypomotility)

26
Q

MOA for Metoclopramide (2)

A

D2 antagonist
Increases Ach release

(this enhances motility and tone of smooth muscle)

27
Q

What are 2 adverse effects of Metoclopramide? In what population is this prokinetic agent C/I?

A
Extrapyramidal sxs (Parkinson's like)
GI cramping + diarrhea

C/I in pregnancy (risk of methemoglobinemia)

28
Q

MOA for Bethanechol

A

Muscarinic agonist

29
Q

What drug is used to tx diabetic gastroparesis? What is the MOA of this drug?

A

Erythromycin (prokinetic agent)

MOA: Macrolide abx, stimulates motilin receptors

30
Q

What 2 drugs are used as antismasotics/tx of IBS?

A

Dicyclomine

Amitriptyline

31
Q

MOA for Dicyclomine. What are the adverse effects?

A

MOA: Blocks muscarinic receptors
SE: sedation, dry mouth, constipation, etc (basically SNS effects)

32
Q

MOA for Amitriptylline in the tx of IBS? (2)

A

Blocks muscarinic receptors

Increased NE release stimulates alpha-2 receptors in spinal cord to DECREASE PAIN

33
Q

The chemoreceptor trigger zone (vomiting center of the brain) is rich in what 4 receptor types?

A

5HT-3
DA
NK-1
Opioid

34
Q

What are the 5 anti-nausea/anti-emetic drugs?

A

Ondansetron (Zofran)
Promethazine (Phenergan)/Prochlorperazine
Dronabinol (THC)
Aprepitant

35
Q

MOA for Ondansetron (Zofran)

A

5HT-3 antagonist

36
Q

MOA for Promethazine (Phenergan) and Prochlorperazine

A

Block D2, muscarinic, and histamine receptors

37
Q

What 3 drugs can be used for chemotherapy induced N/V?

A

Ondansetron (Zofran) (NOT effective for motion sickness)
Dronabinol (THC) (also increases appetite!)
Aprepitant

38
Q

MOA for Aprepitant. What 2 drugs is it typically combined with?

A

NK1 antagonist

usually combined with 5HT-3 antagonist and steroid

39
Q

What are 3 adverse effects of chronic laxative use?

A

Electrolyte imbalances
Dependence
Alterations in bowel function

40
Q

Name the bulk forming laxative. What is its MOA?

A

Psyllium (Metamucil)

Attracts H20, forms soft mass

41
Q

What are 2 adverse effects of Psyllium? What should be included in pt education?

A

AE: Bloating, flatulence

Tell patient to drink plenty of water as Psyllium is high in fiber!

42
Q

How do osmotic laxatives work? Name the 3 drugs included in this class.

A

Magnesium Hydroxide
Lactulose
Polyethylene glycol

Drugs are poorly absorbed salts and sugars in GI tract that hold onto H20 inside the intestine

43
Q

What drug is used to decrease ammonia build up in pts with cirrhosis? Is this used acutely or long-term?

A

Lactulose

*ONLY laxative that should be used long-term!

44
Q

What drug is used for colonoscopy prep? How can this be adjusted to tx constipation?

A

Polyethylene glycol used in LARGE amounts for colonoscopy prep
-Significantly reduced dose used for tx of constipation for up to 7 days

45
Q

What drug is used as a Mucosal Agent? How does it work?

A

Senna

Stimulates peristalsis, enhances secretion, and inhibits water absorption

46
Q

What are 5 general C/I for use of laxatives?

A
N/V
Abd. cramps
Undiagnosed abd. pain
Appendicitis
Intestinal obstruction
47
Q

MOA for Lubiprostone (2). What is used to tx?

A

MOA: Prostaglandin E1 analogue; Increases intestinal fluid secretion by activating ClC-2 chloride channels

Used to soften stool and reduce sxs in WOMEN with IBS-C

48
Q

MOA for Linclotide (2). What is it used to tx?

A

MOA: Activates guanylate cyclase C ( resulting in increased Cl secretion in intestines); Activates CFTR

Used to tx IBS-C or chronic constipation

49
Q

MOA for Loperamide (imodium). What is it used to tx?

A

MOA: Opioid analogue, decreases peristalsis by inhibiting activity of GI tract

Anti-diarrheal med (can be given OTC due to no CNS effects)

50
Q

What are 4 adverse effects of Loperamide (Imodium)?

A

Abd pain
Distention
Constipation
Dry mouth

51
Q

In what 3 situations is the use of Imodium C/I?

A

Diarrhea caused by organisms that penetrate mucosa
Pts w/ ulcerative colitis
Pts w/ hx of drug abuse (opioid)

52
Q

Which anti-inflammatory drug is used for tx of IBS? What is the MOA?

A

Sulfasalazine

MOA: Aminosalicylate; decreases inflammation, bacteria try to active it

53
Q

What is the primary adverse effect of sulfasalazine? In what population is this anti-inflammatory drug C/I?

A

Hypersensitivity

C/I in children (potential for Reyes Syndrome)

54
Q

What drug is used to tx flatulence? How does it work?

A

Simethicone (Gas-X)

Coats and dissipates gas to allow it to pass less noticeably