Gout Rx Add'l Cards Flashcards
Naproxen: treatment for acute or chronic gout?
acute
allopurinol: treatment for acute or chronic gout?
chronic
probenecid: treatment for acute or chronic gout?
chronic
colchicine: treatment for acute or chronic gout?
acute
pegloticase: treatment for acute or chronic gout?
chronic
prednisone: treatment for acute or chronic gout?
acute
what is the biochemical pathway that leads to uric acid generation? what is the enzyme involved?
hypoxanthine –> xanthine –> uric acid enzyme = xanthine oxidase (for both steps)
what are two general sources of uric acid?
-dietary purines -destruction of DNA
uric acid: how many hydroxyl groups?
3
what is the normal steady state plasma uric acid level?
6.8 ml/dl
what are the 4 possible pathways that serum uric acid can take?
-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
for an acute attack of gout, what is the first line drug?
NSAID (usually naproxen, possibly indomethacin)
for an acute attack of gout, what is the second line drug (if NSAID cannot be used)?
colchicine
for an acute attack of gout, what is the third line drug? (if NSAIDs, colchicine cannot be used)?
oral steroid, usually prednisone
what are some medication options if the first, second, and third line drugs for acute gout have cannot be used? (getting desperate here)
-IV steroid -intra-articular steroid injection
naproxen: what is its mechanism of action?
inhibits COX 1 and 2, reducing production of prostaglandins.
naproxen: what are side effects?
gastric upset, gastritis, ulceration, acute renal failure
naproxen: anti-gout, but also a member of what drug classes?
anti-inflammatory, analgesic, antipyretic
colchicine: what two ways does it help with gout?
both acute gout relief and also prevention
colchicine: what are side effects?
nausea, vomiting, diarrhea. usually these are dose-limiting
allopurinol: what is the mechanism of action/
blocks xanthine oxidase. leads to less uric acid production
allopurinol: leads to increased buildup of what? is this problematic?
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!
allopurinol: side effects? how common?
uncommon but severe: -hypersensitivity vasculitis -agranulocytosis -hepatic necrosis -TEN/Steven Johnson syndrome -acute attack of gout
what is TEN/Steven Johnson syndrome?
skin forms large bullae and FALLS OFF
allopurinol: interactions with other drugs?
dramatic increase in toxicity of azathioprine and 6-MP. need to reduce doses of these.
Probenecid: mechanism?
enhances urinary excretion of uric acid. (uricosuria)
Probenecid: contraindicated in what patients?
-prior allergy to this drug -pts with uric acid kidney stones -pts who are already excreting high amts of uric acid in urine.
Probenecid: ideal patient?
chronic gout pt with high serum uric acid but LOW urine uric acid
Probenecid: side effects?
aplastic anemia, hepatic necrosis, allergy, can precipitate an acute attack of gout (focus on the last point here)
pegloticase: mechanism?
-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
pegloticase: route of delivery? frequency?
enzyme so cannot give PO must give IV, every 2 weeks
pegloticase: side effects?
-antibodies develop in 92% of pts (makes it less effective) -anaphylaxis in 5% -precipitate acute effects of gout -recombinant -> expensive!!
