GI

Question 1

Indinavir

Answer 1

MOA:
-Proteas inhibitors are anti-HIV drugs that inhib. cleavage of the polypeptide precursor into mature viral proteins.

Use:
-Part of combination tx. for HIV

Tox:

• Hypergylcemia
• Lipodystrophy
• Drug-drug interaction due to inhib of cyt p-450

Question 2

Penicillamine

Answer 2

MOA:
-Chelating agent that removes excess loosely bound serum copper from tissue

Use:
-Wilson’s disease

Question 3

Tx. of lead poisoning

Answer 3

Dimercaprol, EDTA

Clinical features of lead poisoning:

• Encephalopathy
• Abd colic (pain)

Question 4

Lactulose

Answer 4

MOA:

• Disaccharide that lowers blood ammonia level
• Bacterial action on lactulose acidifies colonic contents, which converts absorbable into non-absorbable ammonium ions, trapping the ammonia in the stool and increasing fecal nitrogen excretion.

Use:
-Hepatic encephalopathy

Question 5

Deferoxamine

Answer 5

MOA:
-Iron chelating agent

Use:
-Hemochromatosis (bronze diabetes)

Question 6

Lansoprazole

Answer 6

MOA:
-PPI, blocks final common pathway of gastric acid secretion from parietal cells, which is stimulated by Ach, histamine and gastrin.

Use:

Question 7

Ribavirin

Answer 7

MOA:
-Multifactorial; includes lethal hypermutation, inhibiting RNA polymerase and inosine monophosphate dehydrogenase (depleting GTP), causing defective 5’-cap formation on viral mRNA transcripts, and modulating a more effected immune response

Use:

• Tx. of chronic HepC
• Tx. of RSV

Question 8

Raltegravir

Answer 8

MOA:

• Inhibits integration of viral DNA into host’s genome
• Inegrase inhibitor

Use:
-Tx. of HIV

Question 9

Amantadine

Answer 9

MOA:
-Impaires host cell uncoating of the influenza A vision after host cell endocytosis

Use:
-Influenza A virus

Question 10

Enfuvirtide

Answer 10

MOA:

• Prevention of viral entry into target cells
• Antiretroviral fusion inhibitor

Use:
-Tx. of HIV

Question 11

Octreotide

Answer 11

MOA:
-Synthetic somatostatin analog; decreases gut motility, blood flow, endocrine and exocrine pancreatic function

Use:
-Carcinoid syndrome

Question 12

Ondansetron

Answer 12

MOA:
-Blocks 5-HT3 serotonin receptors

Use:
-Potent antiemetic mainly used in patients undergoing chemo

Question 13

Loperamide

Answer 13

MOA:

• Opiate; decreases gastric motility
• Can help decrease the vol of diarrhea by slowing intestinal transit and allowing more time for net fluid resorption

Use:
-Diarrhea

Question 14

5-aminosalycilates: Sulfasalazine, Mesalamine

Answer 14

MOA:
-Inhibit cytokine, prostaglandin, and leukotriene synthesis during inflammation

Use:
-IBD–> Crohn’s and UC

Question 15

Bismuth, Sucralfate

Answer 15

MOA:
-Binds to the base of mucosal ulcers, protecting against gastric acid

Use:
-Peptic ulcer disease

Question 16

Metoclopramide

Answer 16

MOA:

• Dopamine antagonist with both central and peripheral effects.
• Prokinetic and antiemetic properties

Use:

• GI motility disorder (gastroparesis)l
• Preventing nausea and vomiting

No significant affect on PUD

Question 17

Misoprostol

Answer 17

MOA:
-Prostaglandin E1 analog

Use:
-To prevent NSAISD-induced ulcer disease

Question 18

Polyethylene glycol

Answer 18

MOA:
-Osmotic laxative

Use:
-Constipation

Question 19

Diphenoxylate

Answer 19

MOA:
-Binds to mu opiate receptors in the GI tract and slows motility

Use:
-Opiate antidiarrheal structurally related to meperidine

Tox:
-Higher doses can lead to euphoria and physical dependence (drug is usually combined with Atropine @ therapeutic doses to discourage abuse)

Question 20

Dimercaperol

Answer 20

MOA:
-Chelating agent that displaces arsenic ions from sulfhydryl groups of enzymes and facilitates their excretion

Use:
-Arsenic poisoning

Tox:
-Nephrotoxicity and Hypertension

Question 21

CaNa2EDTA

Answer 21

MOA:
-Chelating agent that forms complexes with mono, di, and trivalent ions

Use:
-Acute lead and mercury poisoning

Question 22

Amyl nitrite

Answer 22

MOA:
-Forms methemoglobin that binds cyanide ions forming the non-toxic compound cyanomethemoglobinemia thereby preventing cyanide from binding mito enzymes in tissue

Use:
-Cyanide poisoning

Question 23

Methylene blue

Answer 23

MOA:
-Reducing agent, converts iron in heme from the Fe3+ to the Fe2+ state

Use:
-Tx of methemoglobinemia

Question 24

H2 Blockers (cimetidine, ranitidine, famotidin, nizatidine).

Answer 24

MOA: reversible block of histamine H2-receptors –> H+ receptors secretion by parietal cells.

Use: Peptic ulcer, gastritis, mild esophageal reflux

Tox: Cimetidine is a potent inhibitor of cytochrom P-450 (multiple drug interactions); it also has antiandrogenic effects (prolactin release, gynecomastia, impotence, decrease libido in males); can cross blood-brain barrier (confusiojn, dizziness, headaches) ad placenta.

Both cimetidine and ranitidine decreases renal excretion of creatinine.

Other H2 Blockers are relatively free of these effects

Question 25

Proton Pump Inhibitors (omeprazole, lansoprazole, esomeprazole, pantoprazole, dexlansoprazole)

Answer 25

MOA: Irreversibly inhibit H+/K+ ATPase in stomach parietal cells

Use: Peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome

Tox: Increase risk C. difficile infection, pneumonia. Hip fractures, decrease serum Mg2+ with long-term use.

Question 26

Antacid Use

Answer 26

Can affect absorption, bioavailibility, or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying

All can cause hypokalemia

Overuse can also cause the following problems

Question 27

Aluminum hydroxide

Answer 27

constipation and hypophosphatemial; proximal muscle weakness, osteodystrophy, seizures.

Aluminum amount of feces

Question 28

Caclium Carbonate

Answer 28

Hypercalcemia, rebound acid increases

Can chelate and decrease effectiveness of other drugs (e.g. tetracycline)

Question 29

Magnesium Hydroxide

Answer 29

Diarrhea, hyporeflexia, hypotension, cardiac arrest

Mg= Must go to the bathroom

Question 30

Osmotic laxatives (magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose)

Answer 30

MOA:

Use:

Tox: