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Flashcards in Pharmacology Deck (16)
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Mechanism of ribavirin?

- incorporated into RNA as purine and pairs equally well with U and C, leading to hypermutation and lethality
- depletes intracellular GTP (prevents 5' capping)

- direct inhibition of viral polymerase
- enhances immune response

1

Side effect of mu opioid analgesics that results in right upper quadrant pain?

contraction of smooth muscle in the sphincter of Oddi leading to constriction and spasm
increased pressures in bile duct and gall bladder can lead to rare, painful crisis called biliary colic

2

Most common cause of duodenal ulcer? Treatment?

H. pylori (80-95% of cases)
remaining cases associated with NSAID use

Treatment:
- antibiotics to eradicate H.pylori (metronidazole, tetracycline, amoxicillin, clarithromycin)
- adjunctive agent like a proton pump inhibitor or bismuth

3

What is polyethylene glycol? What is the mechanism? Name other drugs in this class.

osmotic laxative
(magnesium hydroxide, magnesium citrate, lactulose)

provides osmotic load to draw water out
used for constipation

4

How to calculate oral bioavailability if you have oral and IV plasma concentrations of drug? What is bioavailability of an IV administered drug?

(area under curve for oral admin.) / (area under curve for IV admin.)

IV-administered frug has 100% bioavailability!

5

Name the H2-blockers. What are they used for?

Cimetidine, ranitidine, famotidine, nizatidine
(suffix -dine)
"Take H2 blockers before you DINE. Table for 2 (H2)."

Uses: peptic ulcer, gastritis, mild esophageal reflux

6

H2 blocker side effects?

Cimetidine:
- potent inhibitor of cytochrome P-450
- antiandrogenic effects (prolactin release, gynecomastia, impotence, decreased libido in males)
- crosses BBB (confusion, dizziness, headaches) and placenta

Cimetidine and ranitidine:
- decreased renal excretion of creatinine

Other H2-blockers are relatively free of these effects

7

Where is iron absorbed in the GI?

predominantly in the duodenum and proximal jejunum

8

35yo with colicky abdominal pain, constipation, irritability, works in battery manufacturing? What are the classic symptoms? Treatment?

Lead poisoning

LEAD
Lead lines on gingivae (Burton lines) and on metaphyses of long bones on X-ray
Encephalopathy and Erythrocytes basophilic stippling
Abdominal colic and sideroblastic Anemia
Drops (wrist and foot drop)

Treatment:
Dimercaprol and EDTA
Succimer used for chelation in kids (SUCks to be a kid that eats lead)

9

Pt presents with vomiting, abdominal pain, garlic breath. What is the treatment for arsenic poisoning?

Dimercaprol
also treats mercury and gold poisoning

10

What is the treatment for iron poisoning from repeated transfusions?

Deferoxamine, deferasirox
chelating agents

11

What is the treatment for cyanide poisoning?

Nitrites (like amyl nitrite) + thiosulfate, hydroxocobalamin

forms methemoglobin that binds cyanide ions with high affinity, thus preventing cyanide from binding mitochondrial enzymes in the tissues

12

What is the treatment for methemoglobin?

methylene blue, vitamin C

methylene blue is a reducing agent that converts iron in heme from the Fe3+ state to the Fe2+ state

13

How do loperamide and diphenoxylate treat diarrhea?

mu opiate anti-diarrheal
binds mu opiate receptors in GI tract and slows motility

14

What is secretory diarrhea and what drugs are used to treat it?

due to excess secretions of fluids and electrolytes in the gut

Treatments: octreotide (somatostatin analogue), bismuth, probiotics

15

Teenager with failure to thrive and history of Pseudomonas respiratory infections? What type of diarrhea would he have? Treatment?

Cystic fibrosis

Steatorrhea due to malabsorption from obstructive fibrosis and progressive insufficiency of exocrine pancreas.

Treatment for diarrhea would include pancreatic lipase supplementation to enhance macronutrient and vitamin absorption.