Gout And RA Flashcards
If NSAIDS or corticosteroids fail in acute gouty attack what is used
Colchicine
Orally every hour until symptoms improve or side effects become intolerable ( nausea, vomiting, diarrhea)
Treatment of an acute attack of gout
NSAIDS- indomethacin, naproxen
Corticosteroids - prednisone
ACTH
Colchicine - what is its moa
Binds to tubulin preventing Tubulin polymerization to form micro tubules
-> the hauls leukocyte migration and phagocytosis.
Also inhibits leukotriene b4 formation
Colchicine what does it do ? Why give it?
It decreases inflammation and pain associated with acute gouty arthritis and is more specific than NSAIDS
- at low doses can be used as a prophylaxis of gouty arthritis
What are side effects of colchicine and contraindications
Gi distress: diarrhea, vomiting,
Enterohepatic circulation : prolongs 1/2 life and increase exposure to GI tract
Acute high dose -> renal failure or bloody diarrhea
Chronic use ->bone marrow suppression, aplastic anemia, thrombocytopenia , alopecia
CONTRAINDICATIONS : renal disease, liver disease or GI disease
What is the goal of treatment for hyperuricemia
Decrease irate contraction to below 6.0 mg/dL
What is probenecid used for?
Increases uric acid elimination and thus decreases the body urate pool in pts with gout but not to be used in patients screwing large amounts of uric acid since it will precipitate Uric acid caliculi in the kidney . PREVENT GOUT ATTACK
What is the MOA of probenecid
Its secreted and reabsorbed from the proximal tubule of the kidney. COMPETES with Uric acid renal tubule anionic transport sites. There is a net decrease in Uric acid reabsorption
What are the side effects of probenecid
Decreases or halts secretion of weak acids ( penicillins)
GI irritation, rash, could aggravate gout at first ( give with colchicine) urate stones in kidney
Contraindications or limitations of giving probenecid
- Pts with decreased function can’t be on it.
- Uricosuric agents may case crystallization of urate if hydration isn’t maintained
- potential for many drug interactions bc stops secretion of weak acids- alter the clearance of many drugs
- methotrexate
- oral hypoglycemics
- zidovudine
Should aspirin be used in pts with gout?
NO ! Well just not in low doses. In low doses it will cause net UA retention by blocking the secretory transports
I large doses it will act as an uricosuric and compete with UA at receptors and therefore decrease the net UA reabsorption
What is allopurinol and what’s it’s MOA
It’s an isomer of hypoxanthine. A newer drug oxypurinol (alloxanthin)is more effective. Irreversibly blocks xanthine oxidase
It’s reduces the urate levels and increases hypoxanthine and xanthine which are more soluble
What is the MOA of methotrexate
NON BIOLOGICS - disease modifying antirheumatic drug
Inhibits dihydrofolate reductase decreases dTMP-> decreases DNA and protein synthesis / anti- inflammatory effect may be due to the enhanced adenosine release
[ dihydrofolate reductase : reduces dihydrofolate to tetrahydrofolate - which is essential for purine synthesis and unveil acid precursors]
What are the uses of methotrexate
RA, psoriasis, lupus , chemo, immunosuppression
Contraindicated with pregnancy
Non- biologic
What are adverse effects and drug interactions with methotrexate
Mucosal clerks, nausea, diarrhea, abnormal liver enzymes, bone marrow suppression
Competition for weak acid secreting pathway in proximal tubule so high dose of aspirin or probenecid can compete for excretion and cause toxicity.
converted to active metabolite in liver so must monitor liver enzymes.
How does febuxosat work and when should it be used
It is a non purine selective inhibitor of XO. I should be used with pts with renal insufficiency bc the liver metabolizes it. It’s chemically different that allopurinol so pts allergic to allopurinol can use this instead. It’s more effective than allopurinol but clinical effect doesn’t appear to be superior
Uricase enzymes what’s wrong with them
Metabolize UA to allantoin. Other species contain this enzyme naturally we don’t. A pegylated form of uricase is used to treat gout but some ppl are allergic and pts will develop antibodies toward it.