katzung: GI Flashcards
What is the moa of antacids?
Name two of them
react with protons to neutralize stomach acid
- magnesium hydroxide: strong laxative effect
- aluminum hydroxide: constipating effect
What is the moa of H2 receptor antagonists?
Name 4
inhibit stomach acid production
cimetidine, ranitidine, famotidine, nizatidine
What are the uses of H2 receptor antagonists?
GERD, peptic ulcer disease, nonulcer dyspepsia
What is the moa of proton pump inhibitors?
Name 4
lipophillic and diffuse into parietal cell canaliculi where they irreversibly inhibit H+/K+ ATPase (this pump produces the stomach acid)
omeprazole, esomeprazole, pantoprazole, rabeprazole
What are the uses of proton pump inhibitors ?
What are the side effects?
more effective in treating GERD and peptic ulcers
side effects: diarrhea, abdominal pain, headache,
chronic treatment may lead to hypergastrinemia
may decrease availability of vit B12
What is the moa of sulcralfate?
binds to injured tissue and forms a protective coating over ulcer beds
accelerates healing of peptic ulcers and reduces their recurrance rate
What is the moa of misoprostol?
PGE1 analog; increases mucosal protection and inhibits acid secretion
What is the moa of colloidal bismuth?
provides a protective coating on ulcerated tissue and stimulates mucosal production as a protective mechanism
direct antimicrobial effects
sequesters enterotoxins
What is the use of colloidal bismuth?
non prescription
reduces stool frequency and liquidity in infectious diarrhea; causes black stool
What is the moaof antibiotics?
chronic infection with H.pylori
-use PPIs, clarithromycin and amoxicillin
(or metronidazole in patients with a penicillin allergy)
What are names of drugs that promote upper GI motility ?
neostigmine, dopamine, metoclopramide, domperidone, erythromycin
What is the moa of neostigmine?
acetylcholinesterase inhibitors that are used to treat hospitalized patients with acute large bowel distention
What is the moa of dopamine?
inhibits cholinergic stimulation of smooth muscle contraction
What is the moa of metoclopramide and domperidone?
D2 dopamine receptor antagonists that promote GI motility
What is the main side effect of metoclopramide?
when used chronically it can induce symptoms of parkinsonism and hyperprolactinemia
What is the moa of erythromycin?
promotes motilin receptors; beneficial in patients with gastroparesis
What are the bulk forming laxatives?
psyllium, methylcellulose, polycarbophil
What are the stool softening laxatives?
docusate, glycerin, mineral oil
What are the osmotic laxatives?
magnesium oxide, sorbitol, laculose, magnesium citrate, sodium phosphate, polyethyleneglycol
Which are the stimulant laxatives?
aloe, senna, cascara, castor oil, bisacodyl
Which are the chloride channel activating laxatives?
lubiprostone
What is the name of the laxative that is an opioid receptor antagonist?
methylnaltrexone, alvimopan
What are the names of some antidiarrheal agents?
they are opioids: diphenoxylate, loperamide
loperamide is available over the counter
the nonprescription ones: kaolin and pectin decrease stool liquidity
What is the mo of the anticholinergic drugs that are used in irritable bowel syndrome?
dicyclomine and hyoscyamine are anti-spasmodics which relieve abdominal pain
What is the moa of alosetron?
potent 5HT3 antagonist
used to treat IBS in women with diarrhea
can cause severe constipation
What is the moa of lubiprostone?
laxative that activates the type 2 chloride channel in small intestines
used in women with IBS who also have predominant constipation
What are the groups of the antiemetic drugs?
H1 histamine blockers antimuscarinic drugs corticosteroids cannabinoid receptor agonist 5HT2 antagonists
What are the H1 histamine blockers?
diphenhydramine, phenothiazines
Which drug has anti muscarinic action as an antiemetic?
scopolamine
Which corticosteroid is an antiemetic?
dexamethasone
Which cannabinoid receptor agonists are antiemetic?
dronabinol, nabilone
What are the names of the 5HT3 antagonists used as antiemetics?
ondansetron, granisetron, dolasetron, palonosetron prevent nausea and vomiting after chemotherapy and anasthesia
Which drug is used topically to treat IBD?
aminosalicyclates are used such as mesalamines which are readily absorbed from the small intestines
What are some other drugs that are used to treat IBD?
balsalazide, olsarazine,sulfasalazine
sulfasalazine has more adverse effects due to systemic absorption of the sulfapyridine motiety
What are some other agents that are used to treat Chron’s disease and ulcerative colitis?
- antibiotics, glucocorticoids
- immunosuppressive antimetabolites: azathiopurine, 6-MP, methotrexate
- anti-TNF such as infliximsb
- natalizumab blocks integrins on the circualting leukocytes
What is the therapy used for pancreatic enzyme replacement?
stetorrhea can be treated by administering a pancreatic lipase called pancrelipase or pancreatin
What is a drug that can inhibit gallstone formation?
these can be inhibited by the bile acid derivative ursodiol which decreases cholesterol secretion by the liver to lower cholesterol content of the bile
