GI pharm

Question 1

GERD and PUD

Answer 1

H2 receptor antagonists
PPI
mucosal protectants
antacids
antiemetics

Question 2

increase protective factors

Answer 2

antacids
sucralfate

Question 3

decrease aggressive factors

Answer 3

H. pylori
target gastric acid secretion: H2 blockers and PPI (parietal cells)

Question 4

H. pylori tm

Answer 4

several abx and gastric acid I
combo therapy to minimize resistance (likes acidic env and most abx dont thrive well there)
need confirmed case before treating bc resistance
10-14 days, adherence not great bc v expensive and up to 12 pills/day

Question 5

cimetidine
famotidine

Answer 5

h2 receptor antagonists
moa: block h2 receptors in stomach, reduce gastric acid secretion 60-70%, increases stomach pH
PO, IV at least 1 hr apart from antacids, OTC
I: GERD, PUD, ulcer prophylaxis - asp pna, heartburn/dyspepsia

Question 6

h2 receptor antagonists: SE

Answer 6

well tolerates, CNS effects in elderly, slight increased risk of pna in elderly
interactions: inhibit cyp450 (cimetidine, thats why famotidine is used 1st line)
can increase warfarin, phenytoin, theophylline bc cyp450 I (esp cimetidine)
give IV slowly to avoid bradycardia

Question 7

PPIs

Answer 7

omeprazole
patopracole
esomeprazole
moa: bind PP, inhibit H/K ATPase enzyme system (proton pump), irreversibly inhibits secretions of HCl - primary driver for stomach acid secretion
more effective than H2RA
I: short term treatment of PUD and GERD

Question 8

PPI SE

Answer 8

short = safe
long (years) = increased risk of pna, bone loss/hip fracture, stomach cancer, benefits outweigh risks for most
few interactions

Question 9

mucosal protectant

Answer 9

sucralfate
sucrose base, aluminum hydroxide
moa: alters when exposed to gastric acid, sticky thick gel -> protective barrier
I: duodenal ulcers, gastric ulcers, chronic gastritis
PO - tablet or suspension, take before you eat

Question 10

sucralfate: SE

Answer 10

no major
may cause C
decrease drug abs, PO take 2 hrs apart

Question 11

antacids: SE

Answer 11

Al and Ca based = c
Mg based = d
Mg + Al = balanced
acid rebound
chelation, altered gastric abs of many drugs (separate by 2hr)

Question 12

antacids

Answer 12

moa: neutralize acid by approximately 50%
I: PUD (heal), GERD (s), stress ulcers (prophyl), heartburn and indigestion (for some)

Question 13

antiemetics

Answer 13

serotonin blockers
antihistamines
anticholinergics
dopamine antagonists
prokinetics

Question 14

ondanestron

Answer 14

serotonin blocker
moa: block serotonin receptors in chemoreceptor trigger zone in brain and in afferent vagal nerves in stomach and SI
PO or IV
I: n/v, esp in chemo/radiation

Question 15

ondanestron: SE

Answer 15

common
mild HA, d, dizzy, c
serotonin S
be aware of other drugs that affect serotonin (SSRI, SNRI, TCA, MAOIs, buspirone, tramadol)

Question 16

antihistamines

Answer 16

dimenhydrinate
meclizine
hydroxyzine
moa: block release of histamine H1 receptors in inner ear
I: treat dizzy and n -> antiemetics and antivertigo associated with motion sickness

Question 17

antihistamines: SE

Answer 17

sedation, drowsy, dizzy
anticholinergic effect!
FALL RISK - esp elderly
not given IV -> tissue necrosis, gangrene

Question 18

dopamine antagonists

Answer 18

prokinetic agent = metoclopramide
moa: block dopamine receptors, increase tone of lower ES (GERD), increase peristalsis in stomach and intestine (diabetic gastroparesis and post op)
I: n/v associated with chemo/radiation/opioids, GI motility issues, paralytic ileus

Question 19

dopamine antagonists: SE

Answer 19

sedation
severe: extrapyramidal symptoms, restlessness, neuroleptic malignant S

Question 20

extrapyramidal s

Answer 20

drug induced movement disorders
metoclopramide + antipsychotic meds
akathisia: may feel restless, tense, constant desire to move
acute dystonia: invol muscle contractions
parkinsonism -> rigid muscles in limbs
tardive dyskinesia -> late onset, progressive S, repetitive facial movements - tongue twisting, cheek puffing, chewing motions, lip smacking, grimacing
neuroleptic malignant S -> worst, life threatening, muscle rigid 1st, fever, drowsy, confusion -> seizure

Question 21

drug therapy for diarrhea

Answer 21

diphenoxylate with atropine
loperamide
moa: decrease intestinal peristalsis, reduce intestinal effluent
SE: drowsy and c
fall and driving precautions esp with other CNS depressants
anticholinergic effects of atropine
serious: cardiac arrest/arrythmias (brady)

Question 22

IBS meds

Answer 22

5 aminosalicylates
DMARDs
not great at treating

Question 23

5 aminosalicylates

Answer 23

sulfasalazine
I: mild - mod IBS
moa: sulfonamide abx that converts intestine into 5 aminosalicyclic acid AND sulphapyridine
sulphapyridine has no therapeutic effect for IBD because of its SE some pt prefer mesalamine alone

Question 24

sulfasalazine: SE

Answer 24

n, fever, rash, HA, hematologic disorders
dont give to pt with sulfa allergy or who have certain types of anemias, caution for use in pt with many diseases - can cause lots of issues

Question 25

DMARDs

Answer 25

infliximab disease modifying antirheumatic drug moa: monoclonal antibody that neutralizes TNF alpha (inflam mediator) I: lots, IBD

Question 26

infliximab: SE

Answer 26

immune suppression: infection, cancer, HF, infusion rxn, neutropenia often require therapeutic drug monitoring and biomarker monitoring for inflam (CRP) screened for TB and other diseases before start, titers drawn, need vax

Question 27

general tm

Answer 27

diet mod, sx, pharm

Question 28

bismuth subsalicylate

Answer 28

adsorbent Coats walls of GI tract, bind causative agent for elimination (adsorption) I: diarrhea SE: Increased bleeding time, constipation, dark stools and tongue darkening Same as aspirin nc: Form of aspirin Activated charcoal also given in drug overdose

Question 29

Loperamide (otc, slowed peristalsis only, no SE) Diphenoxylate (with anticholinergic, Rx)

Answer 29

antimotility moa: Slow peristalsis by reducing rhythmic contractions and smooth muscle tone of GI tract, drying effect due to anticholinergic – reduce gastric secretions I: d SE: Due to anticholinergic: Urinary retention, headache, dizziness, anxiety, drowsiness, bradycardia, hypotension, dry skin, flushing nc: Used alone or in combo with adsorbents and opiates

Question 30

Lactobacillius organisms (Bacid, Culturelle) Saccharomyces boulardii (C. diff)

Answer 30

probiotics moa: replenish bacteria and restore normal flora I: d r/t abx, S. b is for C. diff nc: these bacteria make up majority of normal flora of gut, OTC or Rx strength

Question 31

Docusate sodium Mineral oil

Answer 31

Emollient moa: Both prevent water from moving out of intestines DS - Lubricate fecal material and walls, promote fat absorption into fecal mass (soften stool) MO - lubricate intestines I: DS- Prevent opioid induced constipation MI - fecal impaction SE: Skin rashes, decreased absorption of vitamins NC: DS - given prophylactically for post op MI - PO and PR (rectal) or enema

Question 31

psyllium

Answer 31

Bulk forming laxatives moa: Act similar to dietary fiber, absorb water into intestine – increasing bulk (volume), distend bowel to initiate flex bowel activity and bowel movement I: Okay for long term use Contraindicated for intestinal obstruction or fecal impaction SE: Impaction above strictures, fluid/electrolyte (less than other types of laxatives) imbalance, gas formation, esophageal blockage nc: Action limited to GI tract – no systemic affects Take with lots of water to prevent esophageal obstruction or fecal impaction (should be in 8-12 oz of water)

Question 32

Glycerin Lactulose Polyethylene glycol

Answer 32

hyperosmotic moa: Increase water content in feces; promote distension, peristalsis, and evacuation L: works in colon; reduce blood ammonia levels I: G - common in children – suppository L - reduce blood ammonia levels – use with liver disease and hepatic encephalopathy PG - before diagnostic or surgical bowel procedures – total cleansing of bowel, very potent SE: Abdominal bleeding, rectal irritation, electrolyte imbalance

Question 33

Magnesium salts (Mg citrate, Mg hydroxide, Mg sulfate) Sodium salts

Answer 33

Saline moa: Increase osmotic pressure and draw water into colon I: Constipation SE: Magnesium toxicity (in renal pts), electrolyte imbalance, cramping, diarrhea nc: Work within 3-6 hrs Mg salts available OTC Na salts usually given via fleet enema

Question 34

bisacodyle senna

Answer 34

I: Constipation or whole bowel evacuation – work on entire GI tract SE: Nutrient malabsorption, gastric irritation, e imbalance NC: B - PO and PR OTC