NSAIDs

Question 1

rate limiting step of both leukotriene and prostaglandin synthesis involves what compound

Answer 1

• arachidonic acid

Question 2

function of prostacyclin

Answer 2

• dilates blood vessels
• inhibits platelet aggregation

Question 3

cyclooxygenase acts on arachidonic acid to produce

Answer 3

• prostaglandins
• thromboxane
• prostacyclin

Question 4

Lipoxygenase acts on arachidonic acid to produce

Answer 4

leukotrienes

Question 5

function of thromboxane

Answer 5

• vasoconstrictor
• promotes platelet aggregation

Question 6

function of leukotrienes

Answer 6

• chemotaxis
• bronchospasm

Question 7

MOA of Aspirin (acetylsalicylic acid, ASA)

Answer 7

• nonselective, irreversible inhibitor of COX-1 and COX-2

Question 8

distribution of Aspirin (acetylsalicylic acid, ASA)

Answer 8

• distribution occurs throughout the body tissues and extracellular compartments
  
  • slowly crosses the blood - brain barrier
  • concentration in mucosal cell may reach 20x that in lumen of stomach

Question 9

metabolism of Aspirin (acetylsalicylic acid, ASA)

Answer 9

• low doses: first order kinetics
• high doses: zero order kinetics (above 600 mg)

Question 10

four major effects of Aspirin (acetylsalicylic acid, ASA)

Answer 10

1. antiinflammatory
2. analgesic
3. antipyretic
4. platelet: irreversible inhibition of platelet COX enzyme
   
   • effect lasts 8-10 d

Question 11

platelet effect from Aspirin (acetylsalicylic acid, ASA) lasts how long

Answer 11

• ASA inhibits platelet aggregation for 8-10 days

Question 12

adverse effects of Aspirin (acetylsalicylic acid, ASA)

Answer 12

• respiratory alkalosis, then metabolic and respiratory acidosis
  
  • Aspirin (Salicylates) have biphasic effect on respiration (first stimulation and then depression). Initial respiratory stimulation causes respiratory alkalosis which is followed by respiratory depression and respiratory acidosis as the plasma concentration of aspirin rises to toxic levels

Question 13

aspirin should be avoided in patients with

Answer 13

• 1 week before sx
• labor
• vit K deficiency
• hemophilia
• severe hepatic damage
• gatric ulcer

Question 14

how do low doses of aspirin affect uric acid excretion

Answer 14

• low doses of ASA (1-2 g/day) decreases uric acid excretion and elevates plasma urate concentration

Question 15

how do high doses (>5g/d) of aspirin affect uric acid excretion

Answer 15

• aspirin enhances uric acid excretion and lowers the plasma urate levels

Question 16

effect of aspirin on the lungs

Answer 16

• ASA blocks COX from making products from arachidonic acid, creating a bigger pool of acid for leukotriene synthesis -> bronchospasm -> aspirin asthma

Question 17

effect of ASA on GI

Answer 17

• increased acid production leading to ulceration and/or bleeding
• gastritis
• FYI: prostaglandin(s) physiologically protect the stomach against the onslaught of gastric acid secretion through a negative feed back mechanism which consists of lowering acid production.

Question 18

effect of ASA on kidneys

Answer 18

• acute renal failure
• interstitial nephritis
  
  • inhibit prostaglandin synthesis, leaving actions of vasoconstrictors unopposed

Question 19

effect of ASA on pregnancy

Answer 19

• no teratogenic effect
• but should be stopped during last three months of pregnancy

Question 20

reyes syndrome

Answer 20

• cerebral edema in children with viral infections
• aspirin is contraindicated
• DOC for children with fever is acetaminophen

Question 21

antacids have what effect on ASA absorption

Answer 21

Antacids decrease the absorption of salicylates

Question 22

salicylates compete with what compounds for protein plasma binding sites, thereby causing drug interactions

Answer 22

• T3
• Pen-G
• phenytoin
• biliruben
• naproxen