GI Drugs (Quelle)

Question 1

most effective and first line treatment for hyperacidity and ulcers, these drugs are enteric coated to prevent their activation in the gastric lumen, and are absorbed in the blood for delivery to parietal cells

Answer 1

proton pump inhbitors (omeprazole, lansoprazole)

Question 2

which of the following statements regarding PPIs is FALSE?
A. PPIs have few side effects, which include nausea, abdominal pain and diarrhea
B. PPIs typically lower acid secretion by 90%
C. PPIs quickly inactivate all proton prumps in the parietal cells, which is why one dose is usually effective in clearing symptoms of reflux
D. PPIs are cleared through the liver
E. PPIs interfere with CYP activity, and may increase warfarin concentrations and decrease efficacy of the blood thinner clopidogrel

Answer 2

C. Not all proton pumps are active at any one time, and only those that are active react with these drugs. That is why treatment requires 2-5 days.

Question 3

these drugs block the base level of acid secretion maintained by ECL cells and are excreted by the kidneys

Answer 3

H2 receptor antagonists

Question 4

long term use of this H2 receptor antagonist at high doses may cause galactorrhea in women and decreased sperm count, impotence and gynecomastia in men

Answer 4

cimetidine

Question 5

synthetic analog of PGE1 that can reduce acid secretion up to 90% but because of its very short half life, it is primarily used to prevent NSAID-induced injury

Answer 5

misoprostol

Question 6

treatment for stress ulcers that forms a sticky neutral pH polymer coating which swells and covers the gastric epithelium

Answer 6

sucralfate; can block absorption of other drugs through the stomach

Question 7

fast-acting treatment that neutralizes gastric contents for about 2-3 hours

Answer 7

antacids; Al(OH)3, Mg(OH)2, CaCO3

most preparations combine Mg and Al because they have opposing effects (Mg stimulates emptying and motility while Al delays it; this is helpful in combatting constipation/diarrhea)

Question 8

a general adverse effect associated with acid reducers/blockers is _____ acidity, caused by increased gastrin production that stimulates H+ secretion when the blocking agent is removed

Answer 8

rebound

Question 9

Which of the following is NOT an adverse effect associated with antacid use?
A. Constipation and nausea
B. Osteoporosis and encephalopathy
C. Hypocalcemia
D. Renal failure
E. Drug-drug interactions

Answer 9

C. In using CaCO3, hypercalcemia is a transient side effect in normal patients. Al+3 may cause A, B and D.

Question 10

drug that antagonizes the M1 receptors on ganglion nerves, reducing vagal stimulation of parietal and ECL cells (rarely used because of significant anticholinergic effects)

Answer 10

pirenzepine

Question 11

These prokinetic agents stimulate enterochromaffin cells to release serotonin, which stimulates primary afferent neurons in the mucosa, which cause contraction and relaxation of the longitudinal smooth muscle of the GI tract (peristalsis)

Answer 11

serotonin (5-HT4) receptor agonists: tegaserod and cisapride

Question 12

what is the main severe adverse effect associated with serotonin receptor agonists?

Answer 12

fatal cardiac arrythmias; these drugs are not first line, and are in fact only available through restricted distribution programs

Question 13

why is the approach of simply activating muscarinic receptors (ie, bethanechol, neostigmine methylfulfate) to promote prokinetic activity in the bowel not as effective?

Answer 13

does not mimic the coordinated motiliy of peristalsis

Question 14

how do dopamine antagonists work?

Answer 14

they block the DA receptor, which leads to increased release of AcH and increased contractility (prokinetic agents)

Question 15

this dopamine antagonist is used in dysmotility syndromes and also as an antiemetic; side effects include dystonias, parkonsonian symptoms, tardive dyskinesia, etc.

Answer 15

metoclopramide; used for chemo induced nausea

Question 16

prokinetic agonists that stimulate motility as well as GI secretions, but are not recommended for chronic use

Answer 16

motillin agonists; examples include erythromycin, clarithromycin, azithromycin, which are all macrolide antibiotics

Question 17

_____ laxatives, such as polyethylene glycol, lactulose and magnesium hydroxide, are non absorbable agents that cause water retention; they act as laxatives at low doses and cathartics at high doses

Answer 17

osmotic; salts (ie, anything with Mg or Na) should be avoided in individuals with renal insufficiency, cardiac disease, electrolyte abnormalities, or with diuretic use

Question 18

these laxatives are surfactants that allow the mixing of fatty substances with water; are effective as stool softeners but do not increase frequency of defecation

Answer 18

docusate salts

Question 19

____ laxatives are used orally or rectally and induce mild inflammation leading to reduced water absoprtion and increased motility; generally safe but overdose causes catharsis

Answer 19

irritant (do not chew)

Question 20

fiber based laxatives that stimulate peristalsis/mass action of soft well-formed stools, and include methylcellulose, psyllium, and polycarbophil

Answer 20

bulk forming laxatives; may exacerbate intestinal obstructions

Question 21

this bulk forming agent, which can be used as a laxative, is also used as an antidiarrheal for symptomatic relief of watery stools

Answer 21

polycarbophil

Question 22

antidiarrheal agents that may have CNS effects and are packaged with sub-therapeutic doses of atropine to discourage abuse

Answer 22

opioids (ie, diphenoxylate, difenoxin)

Question 23

antidiarrheal that is an orally administered opioid agonist, has no CNS effects, and is 40-50 times more potent than morphine

Answer 23

loperamide

Question 24

Which of the following statements regarding the antidiarrehal agent octreotide is FALSE?
A. It is a peptide derivative of somatostatin that is used to combat secretory diarrhea of hormone secreting tumors
B. May be used for post-surgical gastric dumping syndrome
C. Should be avoided in patients with pancreatitis, as it can cause further inflammation
D. Long term therapy may result in gallstones
E. Adverse reactions include nausea, bloating, and injection site pain

Answer 24

C. Octreotide is actually indicated for pancreatitis, because it reduces secretory acitivity of the pancreas, which is driving its own inflammatory process, allowing it to rest.

Question 25

antidiarrheal agent that is 99% unabsorbed and eliminated in the feces, has anti-secretory, anti-inflammatory and anti-microbial acitivites, and is commonly included in h. pylori treatments

Answer 25

bismuth

Question 26

Which of the following statements regarding irritable bowel syndrome (IBS) is FALSE?

A. Alosetron is a 5-HT3 antagonist used for its prokinetic effect on constipation predominant IBS
B. IBS is characterized by chronic abdominal pain and bloating with alternating constipation/diarrhea
C. IBS is a poorly understood non-inflammatory bowel disorder
D. Neither Alosetron nor the 5-HT4 agonist Tegaserod are first line remedies for IBS, and should only be used after other therapies have failed
E. Alosetron may reduce visceral sensitivity by reducing sensory and vagal nerve signaling

Answer 26

A. Alosetron is used primary for diarrhea predominant IBS. Tegaserod is the prokinetic agonist used for constipation predominant IBS.

Question 27

this class of drugs that includes 5-HT3 antagonists (ondansetron), dopamine receptor antagonists (metoclopramide) and more specific D2 receptor antagonists (prochlorperazine - useful for motion sickness)

Answer 27

antiemetics

Question 28

class of antiemetics that act mainly on the brainstem and are widely used for motion sickness (work best prophylactically); they are sometimes used for post-operative emesis, though not as often as the 5-HT3 antagonists

Answer 28

antihistamines (H1 antagonists): diphenhydramine, cyclizine, promethazine, hydroxyzine

Question 29

antihistamine that has anticholinergic effects and can be used for patients with abdominal cancer

Answer 29

cyclizine