Chapter 60: Gout Flashcards
Gout
Recurrent inflammatory disorder
Seen mainly in men
Hyperuricemia
Uric acid level greater than 7 mg/dL in men or greater than 6 mg/dL in women
Uric acid crystals deposited in joints, may see tophi on joints
Episodes of severe joint pain (typically in large toe)
Causes
Excessive production of uric acid
Impaired renal excretion of uric acid
Overview of drug therapy for Gout
Short term to relieve symptoms of attack
Infrequent flare-ups (fewer than 3 times/year)
NSAIDs: First-line agents
Glucocorticoids also used
Long term to lower blood levels of uric acid
Three or more times per year
Uricosuric drugs
NSAID use for gout
Indomethacin [Indocin]
Naproxen [Naprosyn]
Diclofenac [Voltaren]
Want tx to start asap
Should see pain relief in fist 24 hr
Agents of first choice for acute gouty arthritis
Better tolerated and more predictable than colchicine
Relief should occur within 24 hours; swelling subsides over the next few days
Adverse effects
Gastrointestinal (GI) ulceration, decreased renal function, fluid retention, increased risk of cardiovascular events
Glucocorticoids for gout
Prednisone
Highly effective in relieving pain
Useful for patients who are hypersensitive to, are unresponsive to, or have medical conditions that contraindicate the use of NSAIDs
Avoid in patients prone to hyperglycemia
Colchicine for gout
Antiinflammatory agent
No longer the first-line drug
Now reserved for patients who are unresponsive to or intolerant of safer agents
Not effective against other antiinflammatory disorders
Colchicine uses
Treats acute gouty attack
Reduces incidences of attack
Aborts an impending attack
Colchicine ADR
Gastrointestinal
Myelosuppression
Myopathy
Colchicine drug interactions
Statins
Muscle injury
P-glycoprotein (PGP) inhibitors
Decrease plasma level for drug
Inhibitors of CYP3A4
Elevated levels of drug in body
Colchicine precautions and contraindications
Older adults
Debilitated patients
Patients with cardiac, renal, hepatic, and GI disease
Pregnant patients
Avoid, unless benefits outweigh risks
Drug Therapy for Hyperuricemia: goals of therapy
Promote dissolution of urate crystals
Prevent new crystal formation
Prevent disease progression
Reduce frequency of acute attacks
Improve quality of life
Note: Because these drugs have no analgesic or antiinflammatory actions, they are not useful in an acute gouty attack
Drug Therapy for Hyperuricemia
Allopurinol
Inhibits uric acid
Febuxostat [Uloric]
Decrease blood levels of gout
Probenecid
Increases uric acid excretion
Pegloticase
Converts uric acid to allantoin, a compound readily excreted by the kidney
Allopurinol [Zyloprim]
Reduces blood levels of uric acid
Current drug of choice for chronic tophaceous gout
Reduces blood uric acid levels
Prevents new tophus formation and causes regression of
tophi that have already formed
Allows joint function to improve
Reversal of hyperuricemia also decreases the risk of nephropathy from deposition of urate crystals in the kidney
Allopurinol [Zyloprim] uses
Chronic tophaceous gout
Hyperuricemia due to chemotherapy
Hyperuricemia that develops secondary to cancer chemotherapy
Certain blood dyscrasias: Polycythemia vera, myeloid metaplasia, leukemia
Allopurinol ADR
Hypersensitivity syndrome
GI effects
Neurologic effects
Use for more than 3 years –prone to cataract formation
Generally well tolerated
Rare but potentially fatal hypersensitivity syndrome
Initial therapy may elicit an acute gouty attack
Allopurinol MOA
Inhibits xanthine oxidase (XO), an enzyme required for uric acid formation
