Gout Drugs Flashcards
the aim of therapy in acute vs. chronic gout
acute: control pain using drugs that limit joint inflammation
chronic: achieve normal con of plasma urate by decreasing its production or increasing its excretion
drugs used to treat acute gout
NSAIDs: especially indomethacin
Colchine
Glucocorticoids
drugs used to treat chronic gout
RAPS
Rasburicase
Allopurinol
Probenecid
Sulfinpyrazone
which NSAID is contraindicated in gout and why
aspirin because it competes with the same mechanism of excretion as uric acid in the proximal tubule of the kidney
adverse of NSAIDs
bleeding
salt and water retention
renal insufficiency
mechanism of colchine
binds to tubulin –> inhibits polymerization and formation of microtubules –> uric acid can’t migrate to affected area
adverse effect of colchine
nausea, vomiting, abdominal pain, diarrhea
MAAN
myopathy, aplastic anemia, alopecia, neutropenia
colchine is more specific for gout so why then has NSAIDs replaced it as therapy for gout
troublesome diarrhea that comes with therapy of colchine
what can be used in acute gout as treatment when unresponsive to NSAIDs and colchine
glucocorticoids
mechanism of allopurinol
inhibits xanthine oxidase hence inhibiting the synthesis of uric acid
why are colchine and NSAIDs used in first 4-6 months of therapy with allopurinol
to prevent acute on chronic attack of gout
adverse effect of allopurinol
hypersensitivity skin rash that can lead to Steven Johnson syndrome
drug interaction with allopurinol
azathioprine and mercaptopurine are purine analogues and are metabolized by xanthine oxidase so if allopurinol is inhibiting the enzyme, you can have toxic levels of these drugs
agents that lower uric acid synthesis vs. increase uric acid secretion name them vs. agent that enhance uric acid metabolism
lower uric acid synthesis: allopurinol
increase uric acid excretion: Probenecid, Sulfinpyrazole
enhance uric acid metabolism: Rasburicase
how do the uricosuric agents aka agents that increase uric acid excretion work
they compete with urate for the brush border transporter that exchanges urate for an organic/inorganic anion which essentially reabsorbs urate while excreting the anions
hence with this competition more urates are excreted
what patients do you not use probenecid in
gouty patients with nephrolithiasis
those with overproduction of uric acid
those with renal insufficiency
what NSAID can antagonize probenecid action
aspirin
adverse effect of probenecid
mild GI irritation
adverse effect of sulfinpyrazone
GI irritation more than probenecid
rash with fever
Depression of hematopoiesis (do not give to those with blood dyscrasia)
drug interaction of sulfinpyrazone
it inhibits warfarin metabolism –> increases bleeding
mechanism of rasburicase
metabolizes uric acid to allantoin which can be easily excreted by kidney
