18- G.I. Drugs Flashcards

1
Q

esomeprazole

A

proton pump inhibitor

  • prodrug that requires acid activation to react with and irreversibly inhibit proton pump
  • do not act directly within gastric lumen, they enter parietal cells from systemic circulation (absorbed in high pH)
  • dosed daily, only active for 2 hours, treatment requires 2-5 days
  • liver clearance via P450 (drug interactions through CYP alterations)
  • few side effects: nausea, ab. pain, constipation, flatulence, diarrhea
  • increase warfarin concentrations
  • decrease activation of clopidogrel
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2
Q

lansoprazole

A

proton pump inhibitor

  • prodrug that requires acid activation to react with and irreversibly inhibit proton pump
  • do not act directly within gastric lumen, they enter parietal cells from systemic circulation (absorbed in high pH)
  • dosed daily, only active for 2 hours, treatment requires 2-5 days
  • liver clearance via P450 (drug interactions through CYP alterations)
  • few side effects: nausea, ab. pain, constipation, flatulence, diarrhea
  • increase warfarin concentrations
  • decrease activation of clopidogrel
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3
Q

omeprazole

A

proton pump inhibitor

  • prodrug that requires acid activation to react with and irreversibly inhibit proton pump
  • do not act directly within gastric lumen, they enter parietal cells from systemic circulation (absorbed in high pH)
  • dosed daily, only active for 2 hours, treatment requires 2-5 days
  • liver clearance via P450 (drug interactions through CYP alterations)
  • few side effects: nausea, ab. pain, constipation, flatulence, diarrhea
  • increase warfarin concentrations
  • decrease activation of clopidogrel
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4
Q

cimetidine

A

H2 receptor antagonist

  • block the base level of acid secretion maintained by ECL cells
  • useful for nocturnal acid secretion, duodenal ulcers, and Zollinger-Ellison syndrome
  • renal excretion via organic cation system
  • Adverse Reactions: diarrhea, headache, drowsiness, fatigue, muscle pain
  • CNS affects in elderly
  • decrease pepsin and intrinsic factor output
  • long term use at high doses decreases testosterone binding to androgen receptor and hydroxylation of estradiol causing galactorrhea (women) and decreased sperm count, impotence, gynecomastia (men)
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5
Q

famotidine

A

H2 receptor antagonist

  • block the base level of acid secretion maintained by ECL cells
  • useful for nocturnal acid secretion, duodenal ulcers, and Zollinger-Ellison syndrome
  • renal excretion via organic cation system
  • Adverse Reactions: diarrhea, headache, drowsiness, fatigue, muscle pain
  • CNS affects in elderly
  • decrease pepsin and intrinsic factor output
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6
Q

ranitidine

A

H2 receptor antagonist

  • block the base level of acid secretion maintained by ECL cells
  • useful for nocturnal acid secretion, duodenal ulcers, and Zollinger-Ellison syndrome
  • renal excretion via organic cation system
  • Adverse Reactions: diarrhea, headache, drowsiness, fatigue, muscle pain
  • CNS affects in elderly
  • decrease pepsin and intrinsic factor output
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7
Q

sucralfate

A

octasulfate of sucrose with Al(OH)3

  • forms a sticky neutral pH polymer coating that swells and covers epithelium
  • used for STRESS ulcers
  • acid activated- take before food and avoid antacids/proton pump inhibitors
  • adverse effects: constipation and can block absorption of other drugs through the stomach
  • contraindicated in GI obstruction
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8
Q

aluminum hydroxide

A

neutralizing antacid

  • neutralize pH of gastric contents
  • fast acting (15 minutes), effects lasting 2-3 hours with food
  • delays emptying and slows motility
  • adverse effects- rebound acid secretion, constipation, nausea,
  • may contribute to osteoporosis and encephalopathy with renal insufficiency, may interfere with GI absorption of other drugs
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9
Q

calcium carbonate

A

neutralizing antacid

  • neutralizes pH of gastric contents
  • fast acting (15 minutes), effects lasting 2-3 hours with food
  • adverse effects- rebound acid secretion, hypercalcemia, may interfere with GI absorption of other drugs
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10
Q

magnesium hydroxide (Milk of Magnesia)

A

neutralizing antacids and osmotic cathartic/laxative salt

  • cause inc. osmotic pressure in GI lumen causing retention of water in stool (cathartics when given at high doses)
  • neutralize pH of acid contents
  • fast acting (15 minutes) lasting effects 2-3 hours with food
  • stimulates gastric emptying and motility
  • adverse effects- rebound acid secretion, may interfere with GI absorption of other drugs
  • CONTRAINDICATED IN RENAL DISEASE
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11
Q

misoprostol

A

prostaglandin analog

  • short acting (3 hours)
  • only used to prevent NSAID-induced injury
  • adverse effects: diarrhea, exacerbate inflammatory bowel disease, increase uterine contractions
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12
Q

pirenzepine

A

M1 antagonist (uncommon in USA)
-blocks neurotransmission in the intramural ganglia resulting in less vagal stimulation of parietal and ECL cells
can reduce basal acid production 40-50%
-significant anticholinergic side effects

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13
Q

bethanechol

A

prokinetic agent

  • aim is to selectively activate M2 and M3 receptors
  • does not activate coordinated motility so it is not a front line approach
  • side effects- bradycardia, flushing, diarrhea, cramps, salivation, blurred vision
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14
Q

cisapride

A

prokinetic agent

  • 5-HT4 receptor agonist and adenylate cyclase stimulant
  • used for GERD and gastroparesis
  • adverse effects- fatal cardiac arrhythmias (strict FDA distribution)
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15
Q

erythromycin

A

prokinetic agent

  • motilin agnoist
  • macrolide antibiotic
  • causes gastric dumping
  • can improve gastric emptying with ileus, scleroderma, and pseudo-obstructions
  • FAST DUMPS can be painful, not recommended for chronic use
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16
Q

metoclopramide

A

prokinetic agent

  • general dopamine receptor antagonist
  • increases lower esophageal sphincter tone and upper GI motility
  • can relieve GERD symptoms but does not promote healing
  • used for N/V in dysmotility, laxative
  • adverse effects- EPS, dystonias, tardive dyskinesia with chronic use
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17
Q

neostigmine

A

prokinetic agent

  • AChE inhibitor
  • can be used acutely to counter an ilues
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18
Q

tegaserod

A

prokinetic agent

  • serotonin partial agnoist in the gut used for females with irritable bowel syndrome
  • can improve lower bowel motility if cases with chronic constipation and bloating
  • adverse effects- fatal cardiac arrhythmias (strict FDA distribution)
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19
Q

magnesium citrate

A

osmotic cathartic/laxative salt

  • cause inc. osmotic pressure in GI lumen causing retention of water in stool (cathartics when given at high doses)
  • small amount absorbed but given at high enough dose to overcome absorption
  • Mg may stimulate CCK and inc. motility
  • should be avoided in those with renal insufficiency, cardiac disease, electrolyte abnormalities, or with diuretic use
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20
Q

magnesium sulfate

A

osmotic cathartic/laxative salt

  • cause inc. osmotic pressure in GI lumen causing retention of water in stool (cathartics when given at high doses)
  • small amount absorbed but given at high enough dose to overcome absorption
  • Mg may stimulate CCK and inc. motility
  • should be avoided in those with renal insufficiency, cardiac disease, electrolyte abnormalities, or with diuretic use
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21
Q

polyethylene glycol (GoLYTELY)

A

osmotic cathartic/laxative alcohol

  • non-absorbable and cause water retention in stool
  • actually cathartics that act as laxatives at lower doses
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22
Q

lactulose (Cephulac)

A

osmotic laxative
-used for constipation assoc. with opioid use and vincristine
-bacterial fermentation drops luminal pH and can trap NH4, which is inc. in patients with hepatic disease
+++can reduce efficacy but may be beneficial in those with hepatic disease

23
Q

mannitol

A

osmotic cathartic/laxative

  • inc. osmotic pressure in GI lumen stimulates peristalsis
  • used for constipation assoc. with opioid use and vincristine
24
Q

sorbitol

A

osmotic cathartic/laxative

  • inc. osmotic pressure in GI lumen stimulates peristalsis
  • used for constipation assoc. with opioid use and vincristine
25
Q

docusate (Colace)

A

stool wetting agent

  • surfactant that allows mixing of fatty substances and water in stool
  • effective as softeners but do NOT inc. frequency of defecation (may inc. frequency but only d/t inc. ease of passing stool)
26
Q

bisacodyl (Dulcolax)

A

irritant laxative

  • used orally or rectally
  • induces moderate inflammation leading to reduced water absorption (inc. water in stool) and inc. motility
  • safe but overdose causes catharsis
  • do not chew tabs or mix with milk/antacids to ensure reaches small intestine intact and avoid gastric irritation
27
Q

castor oil

A

misc. laxative
- general smooth muscle stimulant used as laxative (can also induce labor)
- made from ricinus communis which produces ricin (deadly) and oil full of triglyceride and ricinoleic acid
- ricinoleic acid speeds motility of small bowel

28
Q

glycerin

A

misc. laxative
- suppository that acts as hydroscopic agent and lubricant
- inc. water retention stimulates peristalsis and evacuation reflex
- rectal administration can produce bowel movement within an hour
- cannot be given orally because will not have efficacy

29
Q

methylcellulose

A

bulk-forming laxative

  • fiber based material, not broken down or absorbed
  • bulk material stimulates peristalsis/mass action
  • great for regular/soft stools
  • may exacerbate intestinal obstructions and may absorb other drugs
  • can also function as anti-diarrheal to dec. symptoms of watery stool
30
Q

polycarbophil

A

bulk-forming laxative

  • fiber based material, not broken down or absorbed
  • bulk material stimulates peristalsis/mass action
  • great for regular/soft stools
  • may exacerbate intestinal obstructions and may absorb other drugs
  • can also function as anti-diarrheal to dec. symptoms of watery stool
31
Q

psyllium

A

bulk-forming laxative

  • fiber based material, not broken down or absorbed
  • bulk material stimulates peristalsis/mass action
  • great for regular/soft stools
  • may exacerbate intestinal obstructions and may absorb other drugs
  • can also function as anti-diarrheal to dec. symptoms of watery stool
32
Q

alosetron (Lotronex)

A

antidiarrheal agent

  • 5-HT3 ANTAGONIST used for diarrhea predominant IBS
  • generally produce effects opposite of 5-HT4 agonists
  • may reduce visceral sensitivity by reducing sensory and vagal nerve signaling
  • can produce serious constipation and potentially fatal ischemic colitis
  • only used after failing other therapies
33
Q

bismuth subsalicylate (Pepto-Bismol)

A

antidiarrheal agent
-bismuth
++99% unabsorbed and eliminated in feces
++has anti-secretory, anti-inflammatory, anti-microbial activities
++commonly used in H-Pylori treatments
-salicylate released in acidic environment
++NSAID absorbed systemically
-Mg-Al silicate (clay) (bulk forming effects)

34
Q

diphenoxylate (Lomotil)

A

antidiarrheal agent

  • opioid receptor agonists (Piperidine derivative)
  • Difenoxin is active metabolite
  • can have CNS effects
  • packaged with sub-therapeutic doses of atropine to discourage abuse
35
Q

loperamide (Imodium)

A

antidiarrheal agent

  • mu-opioid receptor antagonist that inhibits bowel motility
  • 40-50x more potent then morphine
  • no CNS effects
36
Q

octreotide (Sandostatin)

A

antidiarrheal agent

  • parenteral derivative of somatostatin (natrual peptide that inhibits pancreatic secretions)
  • used to combate secretory diarrhea of hormone secreting tumors, post-surgical gastric dumping syndrome, and diarrhea assoc. with chemo
  • used to rest pancreas in pancreatitis
  • reduces secretion of serotonin, gastrin, insulin, and secretin
  • S/FX: nausea, bloating
  • long-term therapy may result in gallstones
37
Q

Chlopromazine (Thorazine)

A

antiemetic: DA receptor antagonist/Phenothiazine
-MOA: targets D2 receptors in CTZ and H1 receptors.
+effective for motion sickness
-Adverse effects: parkinson-like Sx and EPS with long-term use
+may lead to dissociative dysphoria

38
Q

cyclizine (Marezine)

A

antiemetic: Antihistamine: H1 receptor antagonist
- MOA: act primarily in the brainstem and vestibular apparatus
- Effective for motion sickness.
- cross BBB so cause sedation.
- also has anticholinergic effects (effective in abdmonial CA).

39
Q

diphenhydramine (Benadryl)

A

antiemetic: Antihistamine: H1 receptor antagonist
- MOA: act primarily in the brainstem and vestibular apparatus
- Effective for motion sickness.
- cross BBB so cause sedation.

40
Q

dimenhydrinate (Dramamine)

A

antiemetic: Antihistamine: H1 receptor antagonist
- MOA: act primarily in the brainstem and vestibular apparatus
- Effective for motion sickness.
- cross BBB so cause sedation.
- salt of diphenhydramine and chlorotheophyllinate (think theophylline)

41
Q

dolasetron (Anzemet)

A

antiemetic: SE receptor (5HT-3) ) antagonist
- Acts centerally at CTZ and STN
- Act peripherally in the intestine.
- t1/2=7-9’
- excretion through liver
- Useful in chemotherapy and emesis promoting states.
- Adverse Rxn: constipation, diarrhea, HA, and light-headedness

42
Q

hydroxyzine (Vistaril)

A

antiemetic: Antihistamine: H1 receptor antagonist
- MOA: act primarily in the brainstem and vestibular apparatus
- Effective for motion sickness.
- cross BBB so cause sedation.

43
Q

granisetron (Kytril)

A

antiemetic: SE receptor (5HT-3) ) antagonist
- Acts centerally at CTZ and STN
- Act peripherally in the intestine.
- t1/2= 9-11.6’
- excretion through liver
- Useful in chemotherapy and emesis promoting states.
- Adverse Rxn: constipation, diarrhea, HA, and light-headedness

44
Q

ondansetron (Zofran)

A

antiemetic: SE receptor (5HT-3) ) antagonist
- Acts centerally at CTZ and STN
- Act peripherally in the intestine.
- t1/2= 3.9’
- excretion through liver
- Useful in chemotherapy and emesis promoting states.
- Adverse Rxn: constipation, diarrhea, HA, and light-headedness

45
Q

paleondansetron (Aloxi)

A

antiemetic: SE receptor (5HT-3) ) antagonist
- Acts centerally at CTZ and STN
- Act peripherally in the intestine.
- t1/2= 40’
- only given IV
- highest affinity for 5HT-3 of this class.
- excreted by kidneys
- Useful in chemotherapy and emesis promoting states.
- Adverse Rxn: constipation, diarrhea, HA, and light-headedness

46
Q

prochlopromazine (Compazine)

A

antiemetic: DA receptor antagonist/Phenothiazine
-MOA: targets D2 receptors in CTZ and H1 receptors.
+effective for motion sickness
-Adverse effects: parkinson-like Sx and EPS with long-term use
+may lead to dissociative dysphoria

47
Q

promethazine (Phenergen)

A

antiemetic: Antihistamine: H1 receptor antagonist
- MOA: act primarily in the brainstem and vestibular apparatus
- Effective for motion sickness.
- cross BBB so cause sedation.

48
Q

Scopoloamine

A

antiemetic: Anticholinergic
-MOA: muscarinic cholinergic antagonist.
+minimal CTZ effects
-effective for motion sickness (vestibular apparatus) and PONV
- Adverse rxn: sedation, dry mouth, blurred vision. May precipitate outburst of uncontrolled behavior when combined with pain of anxiety (remember atropine excitation).

49
Q

6-mercaptopurine

A

purine antagonist (Thiopurine)

  • MOA: metabolized to 6-thioguanine leading to the prevention of DNA synthesis by targeting rapidly proliferating cells.
  • effective for UC and Crohn’s
  • Adverse rxn: pancreatitis, fever, rash, arthraligias, NV, and bone marrow depression.
50
Q

adalimumab (Humira)

A

human antibody (TNF-alpha antibody)

  • somewhat less effective
  • maintain remission for UC and Crohn’s
  • adverse rxn: increased risk for respiratory infection
51
Q

azathioprine (Imuran)

A

thiopurine

  • prevention of DNA synthesis by targeting rapidly proliferating cells.
  • effective for UC and Crohn’s
  • Adverse rxn: pancreatitis, fever, rash, arthraligias, NV, and bone marrow depression.
52
Q

budesonide (entocort)

A

glucocorticosteroid
-effective for IBD 2/2 antiinflammatory and immune effects.
-Adverse rxn: immunosupression, endocrine dysfunction, steroid psychosis, etc
-200x as potent as hydrocortisone but only 10% bio-availability and most is removed via 1st pass effect
+effective for topical Tx inside the bowel

53
Q

infliximab (Remicade)

A

humanized antibody (TNF-alpha antibody)

  • somewhat less effective
  • maintain remission for UC and Crohn’s
  • adverse rxn: increased risk for respiratory infection
54
Q

prednisone (Deltasone)

A

glucocorticosteroid

  • effective for IBD 2/2 antiinflammatory and immune effects.
  • Adverse rxn: immunosupression, endocrine dysfunction, steroid psychosis, etc