GI drugs Flashcards

1
Q

Antibiotics given to fight H. pylori

A

Amoxicillin-preferre
Carithromycin- increasing resistance
Metronidazole-alternative for allergy
Tetracycline-for quadruple therapy

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2
Q

MOA of bismuth subsalicylate

A

antibacterial activity against H. pylori
binds E. coli enterotoxins
forms a barrier
anti-secretory and anti-inflammatory activities of salicylate

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3
Q

Therapeutic use of bismuth subsalicylate

A

PUD, diarrhea, nausea and cramping

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4
Q

Adverse effects of bismuth subsalicylate

A

harmless black discoloration of stool and tongue, salicylism at high doses (tinnitus) Reye’s syndrome, use with caution in children

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5
Q

Antacid prototypes

A

magnesium hydroxide and aluminum hydroxide

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6
Q

MOA of antacids

A

raise stomach pH

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7
Q

Pharmacokinetics of antacids

A

1-2 hrs

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8
Q

Differences between Mg and Al hydroxide

A

Mg2+ -diarrhea due to peristaltic stimulation, Al smooth muscle relaxation

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9
Q

Therapeutic use of antacids

A

largely replaced by more effective, mild symptoms

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10
Q

Drug interactions of antacids

A

can interfere with absorption of other drugs

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11
Q

Prototype histamine receptor antagonists

A

cimetidine

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12
Q

MOA of histamine receptor antagonists

A

blocks acid secretion from parietal cells stimulated by histamine, highly selective for H2

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13
Q

Therapeutic use of H2R antagonists

A

supress total acid secretion by 70%, most effective in suppressing nocturnal acid secretion
Slower onset and longer duration than antacids, prophylactic
Tolerance can develop

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14
Q

Adverse reactions of H2R antagonists

A

edocrine effects- loss of libido, impotence and gynocomastia
CNS effects- rare, in elderly with decreased liver/kidney function
Pneumonia-increased bacterial colonization

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15
Q

Drug interactions with H2R antagonists

A

cimetidine inhibits multiple cyp isoforms

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16
Q

Prototype PPI

A

omeprazole

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17
Q

MOA of PPIs

A

irreversibly inhibits H+, K+ ATPase that are active

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18
Q

Pharmacokinetics of PPI

A

30 min before meals, reduces acid secretion by 95%, effects persist for 2-3 days
Enteric coated to get to small intestine

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19
Q

Metabolism of PPIs

A

hepatic metabolism by CYPs, asian variant correlates with slow metabolism, dose reduction in patients with hepatic disease

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20
Q

Therapeutic uses of PPI

A

PUD, GERD, Zollinger-Ellison syndrome, NSAIDs associated ulcers

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21
Q

Adverse reactions of PPIs

A

nausea, abdominal pain, constipation/diarrhea, flatulence
pneumonia
fractures due to decreased Ca+ absorption
rebound hypersecretion upon discontinuation

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22
Q

Drug interactions with PPIs

A

warfarin, diazepam, cyclosporine

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23
Q

Mucosal protective agent prototype

A

sucralfate

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24
Q

MOA of sucralfate

A

forms a gel at low pH, binds necrotic tissue forming a barrier to acid and pepsin

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25
Q

Therapeutic use of sucralfate

A

duodenal and stress ulcers, stomach pH not increased, does not increase pneumonia risk

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26
Q

Adverse reactions of sucralfate

A

constipation, reduced absorption of other drugs

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27
Q

PGE1 analog prototype

A

misoprostol

28
Q

MOA of misoprostol

A

reduces acid secretion from parietal cells by simulating PGs

29
Q

Therapeutic uses of misoprostol

A

NSAIDS patients, contraindicated in pregnancy (can induce abortions)

30
Q

Adverse effects of misoprostol

A

dose dependent diarrhea and abdominal pain

31
Q

Bulk forming laxative prototype

A

psyllium

32
Q

MOA of psyllium

A

non-digestible agents that swell with water to for a viscous solution that softens and increases stool volume, increasing peristalsis

33
Q

Adverse effects of psyllium

A

must be taken with water to prevent impaction

34
Q

Prototype surfactant laxative

A

docusate sodium

35
Q

MOA of docusate sodium

A

lower surface tension, allow penetration of water

36
Q

Stimulant laxative prototype

A

bisacodyl

37
Q

MOA of bisacodyl

A

stimulates by irritant effects GI motility and increase water and electrolytes in lumen

38
Q

Therapeutic use of bisacodyl

A

widely used, abused
opiod induced constipation
slow intestinal transit constipation

39
Q

Adverse effects of bisacodyl

A

proctitis with long term use

40
Q

Prototype osmotic laxative

A

magnesium hydroxide

41
Q

MOA of magnesium hydroxide

A

poorly absorbed salts or sugars whose osmotic action draws water into the intestinal lumen. causes swelling of stool and stretching of GI wall

42
Q

Therapeutic uses of magnesum hydroxide

A

low dose- group II effect for mild to moderate constipation

high dose-group I effect fluid evacuation of bowel

43
Q

Adverse effects of MgOH

A

can cause dehydration and electrolyte imbalance. Systemic absorption of Mg can cause toxicity

44
Q

Antidiarrheal agents

A

loperamide, diphenoxylate

45
Q

MOA of loperamide and diphenoxylate

A

agonists at myenteric opiate receptors reduces secretory activity (delta) and GI motility (mu)
Loperimide is 50x more potent than morphine

46
Q

Pharmacokinetics of opiod antidiarrheal agents

A

well absorbed orally
Loperamide- poor pentration across the BBB, available OTC
Diphenoxylate- BBB permeable, schedule V, sometimes contain atropine

47
Q

Targets for antiemesis

A

Serotonin acting at 5-HT3 receptors
Dopamine acting at D2 receptors
Substance P/neurokinin 1 (NK1) receptor
Histamine and muscarinic R in vesibular apparatus
glucocorticoid, cannabinoid, GABA and opiod receptors

48
Q

opiod antagonist for opiod induced constipation

A

methylnaltrexone

49
Q

5-HT3 receptor antagonist prototype

A

ondansetron

50
Q

Pharmacokinetics of ondensetron

A

IV, but prophylactic oral, long duration, cleared by CYPs

51
Q

Thereapeutic use of 5-HT3 R antagonists

A

CINV and radiation
pregnancy and postoperative
not effective aginst motion sickness or delayed CINV nausea

52
Q

Adverse effects of 5-HT3R antagonists

A

well-tolerated, constipation/diarrhea, headache

53
Q

Prototype NK1 receptor antagonists

A

aprepitant

54
Q

Pharmacokinetics of aprepitant

A

metabolized by CYP3A4, induces CYP2D6

55
Q

Therapeutic uses of aprepitant

A

delayed nausea, improves efficacy of other agents in CINV

56
Q

Regimen of choice for CINV

A

aprepitant, dexamethasone, 5-HT3 antagonist

57
Q

Treatment for IBS-C

A

dietary fiber (psyllium) and osmotic laxatives

58
Q

Treatment of IBS-D

A

loperamide

59
Q

5-Ht3 R antagonists for IBS-D

A

alsetron

60
Q

MOA of alsetron

A

decreases GI motility and secretions and inhibits unpleasant visceral sensations

61
Q

Therapeutic use of alsetron

A

IBS-D in FEMALE, for severe symptoms lasting longer than 6 months, refractory to all other medications

62
Q

Adverse effects of alsetron

A

severe constipation, life threatening ischemic colitis

63
Q

Mesalamine (5-ASA) based therapy prototype

A

sulfasalazine

64
Q

MOA of sulfasalazine

A

prodrug N=N bond cleaved by intestinal flora to release 5-ASA, which is immune suppressive

65
Q

Adverse effects of sulfasalazine

A

due to metabolite, GI, headaches, arthralgia, myalgia, myelosuppresion

66
Q

Anti-TNF based therapy for IBD

A

inflizimab

67
Q

Side effects of inflizimab

A

injection site and infusion reactions, neutropenia, infection (TB), heart failure, malignancy (lymphomas), pulmonary disease, demyelinating disease, cutaneous reactions, allergic reactions.