GOUT Rx Flashcards
What is uric acid?
metabolite of purines
Uric acid is made from….
via which enzyme?
hypoxanthine -> xanthine -> uric acid
xanthine oxidase
What is the purpose of Uric acid?
contains a lot of nitrogens and is a mechanism by which the body excretes large amounts of nitrogen
When does uric acid tend to precipitate?
High concentrations & Low pH
T/F Solubility of uric acid remains the same at all concentrations
T/F Solubility of uric acid remains the same at all pHs
False
Solubility 200 mg/dL at pH 7.0
Solubility 15 mg/dL at pH 5.0
Where are the 3 final destinations of purines/uric acid?
joints
kidneys
soft tissue
What happens if there is excess deposition of uric acid into joints?
What are the risk factors?
How is this normally treated?
excess uric acid in joint fluid causes phagocytosis and subsequent release of inflammatory cytokines, resulting in inflammation + pain
risk factors: uric acid levels, obesity, OH
Acute attacks: naproxen, colchicine, steroids, otherwise it lasts 3-7d w/o treatment
What happens if there is excess deposition of uric acid into kidneys?
What are the symptoms if this happens?
What is the difference between using low-dose aspirin vs high dose aspirin for pain management in acute attacks?
- excess uric acid in the urine (can precede or follow a gout attack); precipitation favored by acidic urine
- wickedly painful
**low dose aspirin - **
- avoided in acute gout attacks due to paradoxical effects of aspirin on renal handling of uric acid
- increases risk of uric stones
high doses
- uricosuria at higher doses because aspirin actually acts as an anion in the lumen and competes for reabsorption with uric acid (therefore more is excreted)
What happens if there is excess deposition of uric acid into soft tissue?
What do they look like?
excess uric acid in plasma causes crystal deposits in cartilage, tendons, and soft tissues, causing acute and chronic inflammation
Unslightly, but is NOT very painful
Can break through skin and appear as white/yellowish chalky nodules
Acute attacks of gout (4)
1st line? 2nd line? 3rd line? 4th line?
in order of treatment prefrence
- Naproxen (or indomethacin)
- Colchicine PO
- Prednisone PO
- Methylprednisolone, IV or Triamcinolone acetonide, IA
How does naproxen work?
How fast does Naproxen work to alleviate symptoms of Gout?
What are some side effects of naproxen?
Contraindications?
Inhibits COX1/2 -> decreased prostaglandins
relieve severe pain from acute attack within hours-days
ADR: gastric upset, gastritis, ulceration, acute renal failure (edema, fluid retention)
Contraindications: aspirin, patients taking anti-hypertensives (it decreases activity of it)
Why is low dose naproxen contraindicated in patients with acute gout attacks?
paradoxical effects of renal retention of uric acid, which increases risk of crystal precipitation
Why isn’t colchicine used as a first line of Tx?
When would you use colchicine?
When is colchicine contraindcated?
effective, but has unpleasant side effects (nausea, vomiting, diarrhea)
used if NSAID or steroid is not well tolerated
contradincations: erythromycin and other macrolides may increase risk of toxicity
What is the mechanism of colchine?
not entirely clear
may decrease leukocyte migration, phagocytosis, and inflammatory response that is induced by uric acid crystals
When is prednisone used for treatment of acute gout attacks?
3rd line; used when NSAIDs or colchine is not tolerated