Drugs to Treat GI Disorders Flashcards
1
Q
________ drugs are relatively weak inhibitors of acid secretion b/c they act at only one site (M3 receptor mediated by acetylcholine), used as adjuncts to other therapies
A
anti-muscarinic
2
Q
- family of peptide hormones formed by gastric mucosal cells
- stimulates gastric motility, HCl and pepsin secretion
- no direct antagonists
A
gastrin
3
Q
- reduce gastrin secretion
- block histamine induced cAMP and proton pump activation
A
H2 antagonists
4
Q
- irreversibly inhibit the parietal cell H/K ATPase
- all prodrugs that are inactive at neutral pH, activation requires acid environment (take w/ meals so food can stimulate acid secretion)
- unstable at low pH –> have enteric coated granules that dissolve only at alkaline pH
- prodrug absorbed in intestines, carried to circulation to parietal cells, accumulates in secretory canaliculi
- activated at acid pH and bind sulfhydryl groups on H/K ATPase
A
proton pump inhibitors
5
Q
PPIs retain efficacy with chronic use b/c intracellular canaliculi are ________ from the proton pump target at the luminal membrane
A
upstream
6
Q
- prazoles
- currently most effective drugs for suppressing gastric acid secretion b/c gastric response to all stimuli is inhibited
A
PPIs
7
Q
adverse effects of this drug:
- GI effects: colic, flatulence, constipation, diarrhea
- CNS
- skin rash
- prolonged use - diarrhea due to GIT bacteria overgrowth from removal of natural acid barrier
- hepatic metabolism
A
PPIs adverse effects
8
Q
cimetidine, famotidine, nizatadine, ranitidine
A
H2 receptor antagonists
9
Q
- OTC preps that inhibit acid secretion for <6 hours
- block H2 receptors selectively to reduce gastric acid and pepsin secretion without affecting H/K ATPase, H1, or other receptors
- effective against noctural secretion which is largely driven by histamine
A
H2 receptor antagonists (-dines)
10
Q
side effects of this drug
- extremely safe, minor and infrequent adverse effects
- don’t give to pregnant or nursing women
- diarrhea, headaches, fatigue, myalgias, constipation, bradycardia
- confusion, hallucinations, agitation with IV admin in hepatic dysfunction
A
H2 receptor antagonists
11
Q
- this drug causes gynecomastia or impotence in men, galactorrhea in women
- endocrine effects b/c it inhibits binding of dihydrotestosterone to androgen receptors, inhibits estradiol metabolism, increases serum prolactin
- interferes with CYP450 paths
A
cimetidine (H2 receptor antagonist)
12
Q
- all equally effective for healing and preventing recurrence of PUD
- given 1X daily at bedtime to suppress nocturnal acid secretion
- use declined following PPIs
A
H2 antagonists (-dines)
13
Q
- 20% failure in ulcer patients who smoke and in the elderly
- don’t use in combo with PPIs, reduce efficacy by reducing acid activation
- combined with abx and bismuth for treatment of Hpylori
A
uses of H2 antagonists
14
Q
- aluminum hydroxide
- calcium carbonate
- combo aluminum hydroxide and magnesium hydroxide
A
antacids
15
Q
- act by reducing gastric acidity, inactivating pepsin
- weak bases that neutralize gastric HCl to form salt and water, may interfere with absorption of other drugs
- may provide mucosal protection by stimulating PG synthesis
A
antacids
16
Q
- aluminum or magnesium hydroxide
- single dose given 1 hr after eating neutralizes for 2 hours
- side effects: diarrhea for magnesium, constipation for aluminum
- used as needed to relieve pain in esophagitis, peptic ulcer, and GERD
- not recommended for treatment of active peptic ulcers
A
antacids
17
Q
- protective coating on peptic ulcers, limits exposure to acid and pepsin
- sucralfate binds selectively to necrotic ulcer tissue and acts as barrier
A
mucosal protective agents
18
Q
- polymerizes to produce viscous gel that adheres strongly to epithelial cells and ulcer craters in acid environment
- effective in healing duodenal ulcers
- side effect: constipation
- requires acid pH for activation, don’t give with antacids/H2 antagonist/PPI
A
sucralfate
19
Q
- methyl analog of PGE1
- binds PG receptors on parietal cells to inhibit acid secretion
- because NSAIDS inhibit PG formation, it’s used to prevent NSAID induced ulcers
- adverse: diarrhea, abdominal pain
- may cause abortion by stimulating uterine contractions
A
misoprostol
20
Q
- colloidal bismuth
- protective coating of ulcers, antibacterial against Hpylori
- darken tongue and stool
A
bismuth subsalicylate (pepto bismol)
21
Q
antibiotic regimen for Hpylori?
A
clarithromycin + amoxicillin + PPI
22
Q
- nonabsorbable salts containing magnesium cations (magnesium citrate) or phosphate anions (sodium phosphate)
- act by osmotic force to hold water inside intestines –> distended intestines –> stimulate peristalsis
- intensely bitter taste masked by citrus
- avoid in renal insufficiency, heart disease, electrolye imbalance, diuretic co treatment
A
saline laxatives
23
Q
-trihydroxy alcohol that acts in the rectum as lubricant and hygroscopic agent –> water retention –> stimulate peristalsis
A
glycerin
24
Q
- nonabsorbable sugars
- hydrolyzed to organic acids - acidify luminal contents - draw water into lumen - increase colonic propulsive motility
A
lactulose, sorbitol, mannitol
25
- poorly absorbed, retain added water by their high osmotic pressure
- colonoscopy prep, drink 3-4 liters over 3-4 hours to produce watery diarrhea and remove solid wastes
PEG-electrolyte solutions
26
- act directly on enterocytes, enteric neurons, and muscle
| - induce low grade intestinal inflammation, water and electrolytes accumulate, increase intestinal motility
stimulant or irritant laxatives
27
- a diphenylmethane derivative, available as enteric coated tablets taken at bedtime to take effect next morning
- swallow to avoid activation in stomach
bisacodyl
28
- stimulant/irritant laxative
- poorly absorbed in small intestine and require activation in colon with effects 6-12 hours later
- long term use: melanomic pigmentation of colon, cathartic colon (dilated, ahaustral)
anthraquinones - aloe, cascara sagrada, senna
29
-stimulant/irritant: increases intestinal secretion and motility, seldom used due to unpleasant taste and toxic potential
castor oil (ricinoleic acid)
30
methylcellulose, lactulose, polycarbophil
bulk forming laxatives
31
mineral oil, glycerin suppositories, docusate sodium
stool softeners - facilitate expulsion
32
often prescribed to prevent straining in hospitalized patients
docusate
33
loperamide, diphenoxylate, difenozin, bismuth salicylate, kaolin/pectin
antidiarrheal drugs
34
act on intestinal opioid receptors - inhibit Ach release - decrease motility (peristalsis)
loperamide, difenoxin, diphenoxylate
35
- 40-50X more effective than morphine for diarrhea, does not cross BBB
- relief of acute nonspecific diarrhea
- effective against traveler's diarrhea
- more effective than diphenoxylate
loperamide
36
- act by absorbing compounds and presumably binding potential intestinal toxins
- antidiarrheal
kaolin and pectin
37
-antidiarrheal that inhibits intestinal secretions, management of infectious diarrhea
bismuth salicylate
38
- antidiarrheal: inhibits secretion of gastrin, cholecystokinin, glucagon, growth hormone, insulin, secretin, pancreatic polypeptide, VIP, 5-HT
- reduces intestinal fluid and pancreatic secretion
- slows GI motility and inhibits gallbladder contraction
- reduces portal and splanchnic bloodflow
somatostatin/octreotide
39
- first generation H1 blockers
- produce sedation and antimuscarinic activity
- prevent motion sickness
- dimenhydrinate, diphenhydramine, cyclizine, meclizine
anti-emetics: histamine H1 antagonists
40
metoclopramide, trimethobenzamide
D2 antagonists (anti-emetic)
41
ondansetron, granisetron, dolasetron
5-HT3 antagonists, chemotherapy anti-emetics
42
aprepitant, fosaprepitant, rolapitant
NK-1 antagonists, anti-emetic
43
chorpromazine, prochlorperazine
phenothiazines, anti-emetic
44
THC, dronabinol
marijuana derivatives - anti-emetic
45
- low doses of amitriptyline or desipiramine
| - treatment of abdominal pain
tricyclic antidepressants - treat IBS
46
anticholinergics (dicyclomine, hyoscyamine)
antispasmodics - IBS treatment
47
- tegaserod
- emergency treatment only
- CV effects
5-HT4 partial agonist, IBS treatment
48
- 5HT3 antagonist, for IBS treatment
- diarrhea prominent IBS
- serious CV events can occur
alosetron
49
- diarrhea prominent IBS treament
- opioid agonist/antagonist
- reduces neuronal drive on peristalsis
- spasm in sphincter of Oddi can cause pancreatitis
eluxadoline
50
- diarrhea prominent IBS treatment
- synthetic antibiotic similar to rifampin
- may alter bacterial content of GI tract
rifaximin
51
- pancreatic insufficiency can lead to steatorrhea, azotorrhea, vitamin malabsorption, weight loss
- enzyme supplements _______ and _______ treat enzyme insufficiency
- administer with each meal and snack
- can lead to hyperuricosuria and renal stones
pancreatin, pancrelipase
52
- antiobesity
- targets gut, GI lipase inhibitor
- reduces absorption of fats since triglycerides not split
- toxicity: flatulence, steatorrhea, fecal incontinence
orlistat
53
- target CNS, SERT and NET inhibitor
- reduces appetite
- CV effects: tachycardia, hypertension
sibutramine
54
targets CNS, a CB1 receptor antagonist, reduces appetite
| -toxicity: depression, anxiety, nausea
rimonabant
