Gout Rx Add'l Cards

Question 1

Naproxen: treatment for acute or chronic gout?

Answer 1

acute

Question 2

allopurinol: treatment for acute or chronic gout?

Answer 2

chronic

Question 3

probenecid: treatment for acute or chronic gout?

Answer 3

chronic

Question 4

colchicine: treatment for acute or chronic gout?

Answer 4

acute

Question 5

pegloticase: treatment for acute or chronic gout?

Answer 5

chronic

Question 6

prednisone: treatment for acute or chronic gout?

Answer 6

acute

Question 7

what is the biochemical pathway that leads to uric acid generation? what is the enzyme involved?

Answer 7

hypoxanthine –> xanthine –> uric acid enzyme = xanthine oxidase (for both steps)

Question 8

what are two general sources of uric acid?

Answer 8

-dietary purines -destruction of DNA

Question 9

uric acid: how many hydroxyl groups?

Answer 9

3

Question 10

what is the normal steady state plasma uric acid level?

Answer 10

6.8 ml/dl

Question 11

what are the 4 possible pathways that serum uric acid can take?

Answer 11

-can go to the kidney for excretion -can go to the joints and cause gout -can go to the kidney and cause kidney stones -can go to the soft tissues and cause tophi

Question 12

for an acute attack of gout, what is the first line drug?

Answer 12

NSAID (usually naproxen, possibly indomethacin)

Question 13

for an acute attack of gout, what is the second line drug (if NSAID cannot be used)?

Answer 13

colchicine

Question 14

for an acute attack of gout, what is the third line drug? (if NSAIDs, colchicine cannot be used)?

Answer 14

oral steroid, usually prednisone

Question 15

what are some medication options if the first, second, and third line drugs for acute gout have cannot be used? (getting desperate here)

Answer 15

-IV steroid -intra-articular steroid injection

Question 16

naproxen: what is its mechanism of action?

Answer 16

inhibits COX 1 and 2, reducing production of prostaglandins.

Question 17

naproxen: what are side effects?

Answer 17

gastric upset, gastritis, ulceration, acute renal failure

Question 18

naproxen: anti-gout, but also a member of what drug classes?

Answer 18

anti-inflammatory, analgesic, antipyretic

Question 19

colchicine: what two ways does it help with gout?

Answer 19

both acute gout relief and also prevention

Question 20

colchicine: what are side effects?

Answer 20

nausea, vomiting, diarrhea. usually these are dose-limiting

Question 21

allopurinol: what is the mechanism of action/

Answer 21

blocks xanthine oxidase. leads to less uric acid production

Question 22

allopurinol: leads to increased buildup of what? is this problematic?

Answer 22

incr buildup of uric acid precursors: hypoxanthine and xanthine. not problematic as these are more soluble than uric acid. don’t cause gout or kidney stones.

Actually this is problematic! Allopurinol can precipitate an acute gout attack for this reason and this is why colchicine is recommended for coadministration early on to prevent gout flares!

Question 23

allopurinol: side effects? how common?

Answer 23

uncommon but severe: -hypersensitivity vasculitis -agranulocytosis -hepatic necrosis -TEN/Steven Johnson syndrome -acute attack of gout

Question 24

what is TEN/Steven Johnson syndrome?

Answer 24

skin forms large bullae and FALLS OFF

Question 25

allopurinol: interactions with other drugs?

Answer 25

dramatic increase in toxicity of azathioprine and 6-MP. need to reduce doses of these.

Question 26

Probenecid: mechanism?

Answer 26

enhances urinary excretion of uric acid. (uricosuria)

Question 27

Probenecid: contraindicated in what patients?

Answer 27

-prior allergy to this drug -pts with uric acid kidney stones -pts who are already excreting high amts of uric acid in urine.

Question 28

Probenecid: ideal patient?

Answer 28

chronic gout pt with high serum uric acid but LOW urine uric acid

Question 29

Probenecid: side effects?

Answer 29

aplastic anemia, hepatic necrosis, allergy, can precipitate an acute attack of gout (focus on the last point here)

Question 30

pegloticase: mechanism?

Answer 30

-enzyme -catalyzes oxidation of uric acid to allantoin, which is inert and can be excreted. -adds PEG (polyethylene glycol) group to endogenous urate oxidase so it stays in body longer, can catalyze more reactions

Question 31

pegloticase: route of delivery? frequency?

Answer 31

enzyme so cannot give PO must give IV, every 2 weeks

Question 32

pegloticase: side effects?

Answer 32

-antibodies develop in 92% of pts (makes it less effective) -anaphylaxis in 5% -precipitate acute effects of gout -recombinant -\> expensive!!