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Flashcards in GI Deck (69):
1

Antacids

sodium bicarbonate
calcium bicarbonate
magnesium hydroxide/aluminum hydroxide

2

H2-R blockers

"-tidine"
famotidine

3

Proton pump inhibitors

"-prazole"
omeprazole

4

Mucosal protective agents

sucralfate
misoprostol
bismuth subsalicylate

5

bulk forming laxatives

psyllium
methylcellulose
polycarbophil

6

stool softeners

docusate
glycerin

7

saline laxatives

magnesium sulfate
magnesium hydroxide
magnesium citrate
sodium phosphate

8

non-digestible sugars/alcohols

lactulose

9

PEG solutions

golytely
moviprep
trilyte
miralax

10

stimulant laxatives

bisacodyl
senna

11

opioid receptor antagonists

methylnaltrexone
alvimopan

12

bile acid sequesterants

cholestyramine
colestipol
colesevalam

13

HAV general

fecal-oral
no vertical transmission
does not become chronic
vaccines available

14

HBV general

bloodborne
vertical transmission
possibly chronic
vaccines available

15

HCV general

bloodborne
vertical transmission
likely chronic

16

HCV genotypes

1, 4, 5, 6--difficult to treat
2,3--responsive

17

HCV tx

depends on genotype, cirrhosis, tx naive?

18

IgG HAV

-sterile prep of concentrated antibodies
-most effective first 2 weeks of exposure and prior to symptoms (want to stop progression)
-given to those who can't receive vaccine or have been exposed
-cannot receive live vaccine for 6 months after tx

19

IgG HBV (HBIG)

expensive
conservative tx

20

NIH recommendations for HBV tx

don't recommend tx if ALT/liver bx normal OR HBV DNA present but not HBsAg (unless pt is immunosuppressed)

21

Interferon alpha

enhances host immune system
use when IgG won't help
bad adverse effects

22

Antivirals

-lifelong therapy if pt has high cirrhosis (high risk of reactivation)
-can consider d/c in low risk pt who will be followed long term
-watch in co-infected pt (HIV)

23

Source HBsAg positive, unvaccinated

HBIG (1) + HB series

24

Source HBsAg positive, vaccinated

no tx

25

Source HBsAg positive, vaccinated, non-responder

HBIG (1) + HB series
or
HBIG (2)

26

Source HBsAg positive, vaccinated w/unknown antibody response

test exposed person
-positive: no tx
-negative: HBIG (1) + booster

27

Source HBsAg negative, unvaccinated

HB series

28

Source HBsAg negative, vaccinated, vaccinated non responder, vaccinated w/unknown antibody response

no tx

29

source unknown, unvaccinated

HB series

30

source unknown, vaccinated responder

no tx

31

source unknown, vaccinated non responder

if perceived risk, treat as if source was positive

32

source unknown, vaccinated w/unknown antibody response

test exposed person:
-positive: no tx
-negative: booster and recheck in 1-2 months

33

Ribavirin

not mono therapy
adverse effects: hemolytic anemia, teratogenic
major drug interactions

34

antacids general info

weak bases that neutralize stomach acid
--increase frequency not dose
--impair absorption of iron and some abx w/long term use

35

sodium bicarbonate (baking soda, alka seltzer)

--gastric distention/belching (discomfort)
--metabolic alkalosis
--NaCl formation: potential issue in pt w/HTN, renal insufficiency, heart failure

36

calcium bicarbonate (Tums)

belching, bloating, constipation, hypercalcemia, milk-alkali syndrome

minimal renal excretion (hard to break down)

37

Magnesium hydroxide/aluminum hydroxide (mylanta, Maalox)

no gas generated (no concern for metabolic alkalosis)
--renally excreted
--diarrhea or constipation

38

famotidine (Pepcid)

10-12 hour duration of action
most potent, most selective
50% oral bioavailability
available IV

39

H2-R blockers general

elderly have 50% clearance/decreased Vd (toxicity)
--renal impairment needs dose adjustment
--drugs similar to histamine, competitively inhibit parietal H2-R (decreases ACh and gastrin effectiveness)
--great nocturnal acid secretion control
--safe
--IV may use mental status changes in some pt

40

nizatidine (Axid)

10 hour duration of action
100% bioavailability

41

Ranitidine (Zantac)

6-8 hours duration of action
available IV

42

Cimetidine (Tagamet)

4-5 hours DoA (least potent, lot of drug interactions)
CYP1A2, 2C19, 2D6, 3A4

long term: gynecomastia or galactorrhea

used to treat skin condition

43

PPIs general info

--all are prodrugs, sensitive to acid degradation (coating)
--all equally protective at equivalent doses (theoretically)
--irreversibly binds H+/K+-ATPase
--half life 1-5 hours
--full efficacy=1-3 days
--give 1 hour before meal
--hepatic metabolism
--asians

44

PPI IV formulations

esomeprazole
pantoprazole

continuous IV for a few days in pt who cannot eat

45

PPI adverse effects

--diarrhea, headache, stomach pain
--long term: B12 and calcium deficiency
--infection (c-diff, pneumonia)
--rare drug interactions
--affect bioavailability of drugs needing acidic environments (anti-fungals)

46

PPIs and clopidogrel

PPIs decrease prodrug conversion of clopidogrel

only give rabeprazole/ pantoprazole (no interactions); only if absolutely necessary

47

sucralfate

hard regimen, not used often

-protective coating on ulcers/erosions
-empty stomach, 1 hour before food (or 2 hours after eating)
-no side effects
-can bind other drugs and impair absorption
-give w/acid suppressor

48

misoprostol

prostaglandin E1 analog--increases mucosal blood flow, stimulates mucus/ bicarbonate secretion
short half life
protectant for long term NSAID therapy

can cause miscarriage!
diarrhea, cramping

49

bismuth subsalicylate (pepto bismol)

bismuth not absorbed, salicylate absorbed/renally excreted
MoA: coats erosions/ulcers
can increase prostaglandins, bicarbonate, mucus

caution in renal impairment

high doses can cause salicylate toxicity

50

GERD tx

PPI first choice
H2-R blocker BID second choice (use to taper after PPI taper)
treat underlying cause

51

Peptic ulcer disease

H2-R blocker: give nocturnal to help w/healing
PPI: rapid healing
NSAID ulcers: d/c NSAID, PPI for prophylaxis/tx
H. pylori ulcer: PPI w/abx (H2-R blocker used if H. pylori cannot be eradicated)
Rebleeds: PPI

52

Stress ulcer prophylaxis

H2-R blockers preferred IV

53

H. pylori

PPI and abx

54

bulk forming laxatives general info

--hydrophilic colloids that absorb water, indigestible, forms bulky get to stimulate peristalsis
--more helpful for diarrhea than constipation (Can just contribute to constipation if peristalsis not started)
--1-3 days to work
--doesn't help opioid induced constipation

55

stool softeners general info

--MoA: softens stool
--1-3 days to work
--helpful for pellet poop
--sometimes given w/laxative

56

saline laxatives general info

draw water into colon to cause distention/peristalsis
colon prep
use caution in pt w/renal insufficiency, electrolyte imbalance, cardiac disease/those on diuretics

1-3 hours to work

57

lactulose

--treats constipation from opioids, in elderly, idiopathic
15-30mL bedtime (20-30g tid-qid--actually treating hepatic encephalopathy)
--abdominal discomfort and distention subsides w/continued use
--1-3 days to work

58

polyethylene glycol electrolyte solutions (PEG)
general info

colon preps
first choice for opioid constipation
no significant side effects
mix w/water before taking

59

stimulant laxatives general info

stimulate motility through variety of non-understood mechanisms

60

bisacodyl (dulcolax)

--tablet or suppository
--don't use for more than 10 days (atonic colon)
--combo therapy w/PEG for colonoscopy prep
--overnight relief (take near bathroom)

61

Senna (senokot, ex-lax)

--gut bacteria converts to active form
--poorly absorbed
--long term use not harmful
--periclase: Senna and colace

62

lubiprosone (amitiza)

--used for chronic idiopathic constipation, IBS-C, or opioid induced constipation w/pt w/non cancer pain
--stimulate CIC-2 (type 2 chloride channels) to increase fluid secretion and increase motility
--poor bioavailability
--decreased efficacy when given w/methadone
--no cytochrome involvement
--contraindicated in obstruction

63

opioid receptor antagonists general info

doesn't cross BBB, affects opioid receptors in gut

64

diarrhea tx

bulk forming agents
bismuth
loperamide
bile acid sequesterants
diphenoxylate/difenoxin

65

bismuth

anti-secretory
anti-inflammatory
anti-microbial

use in traveler's diarrhea

66

Loperamide (Imodium)

--opioid agonist 50x more potent than morphine
--doesn't cross BBB
--d/c if no improvement in 48 hours
--used in long term chronic diarrhea
--can take a few days to work

67

bile acid sequesterants general info

good for pt w/malabsorption of bile salts (Chrons, surgical gut resection)
--used to lower lipid profile/cholesterol
--use cautiously (can cause impaction)
--binds drugs (2 hour separation b/w other drugs and this)

68

diphenoxylate and difenoxin

crosses BBB, formulated w/atropine to discourage abuse
--can cause constipation/toxic megacolon
--not first line, not great for diarrhea

69

other diarrhea options

codeine
paregoric
octreotide
clonidine
promethazine
cola syrup