Indications
Chronic management of hyperuricemia in patients with
a history of gout.
Action
Decreases production of uric acid by inhibiting xanthine
oxidase. Therapeutic Effects: Lowering of serum
uric acid levels with resultant decrease in gouty attacks.
Pharmacokinetics
Absorption: Well absorbed (49%) following oral
administration.
Distribution: Unknown.
Protein Binding: 99.2%.
Metabolism and Excretion: Extensively metabolized
by the liver; minimal renal excretion of unchanged
drug, 45% eliminated in feces as unchanged drug, remainder
is eliminated in urine and feces as inactive metabolites.
Half-life: 5–8 hr.
TIME/ACTION PROFILE (blood levels)
ROUTE ONSET PEAK DURATION
PO rapid 1–1.5 hr* 24 hr
*Maximum lowering of uric acid may take 2 wk.
Contraindications/Precautions
Contraindicated in: Concurrent azathioprine or
mercaptopurine.
Use Cautiously in: Severe renal impairment (CCr
30 mL/min); Severe hepatic impairment; OB: Use only
when potential maternal benefit outweighs potential fetal
risk; Lactation: Unknown if excreted into breast
milk; use caution when breast feeding; Pedi: Safety in
children 18 yr not established.
Adverse Reactions/Side Effects
GI:qliver function tests, nausea. Derm: rash. MS:
gout flare, arthralgia.
Interactions
Drug-Drug: Significantlyqlevels of and risk of serious
toxicity from azathioprine and mercaptopurine;
concurrent use is contraindicated. Mayqlevels of
theophylline; use cautiously together.
Route/Dosage
PO (Adults): 40 mg once daily initially; if serum uric
acid does notpto 6 mg/dL, dose should beqto 80
mg once daily.
Availability
Tablets: 40 mg, 80 mg.
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