Pharmacology Of Gout in CKD patients Flashcards
Why do humans get gout but other mammals dont?
Humans lack uricase enzymes which are used to break purines down into water-soluble substance allantoin
Requires humans to secrete purines into urine via uric acid form
What are the 4 steps in general management of gout?
1) lower serum uric acid levels (<6mg and <5mg if they have tophi present)
2) provide prophylaxis while intimating urate lowering therapies
- starting sooner prophylactic ULT therapy the better (especially true in CKD > or equal to stage 2)
3) treat gout flares
4) optimize dietary and lifestyle factors
Why is tart cherry juice a recommended dietary supplement for gout patients?
It naturally inhibt is xanthine oxidase
What is lesch-Nyhan syndrome?
Inherited loss of HGPRT enzyme which causes build up of hypoxanthine, guanine and PRPP.
Why does CKD/kidney failure cause gout?
URAT1 receptors in the kidney tubules become hyper functional and upregulated
This causes more uric acid to be reabsorbed in the blood stream and less in the urine
What medications can you not give for gout in CKD patients
NSAIDS (usually starting at stage 3 and higher)
Colchicine needs to reduced
Sulfinpyrazone (dont use)
How does colchicine dosing change in CKD patients
If they are less than stage 3, use loading dose of 1.2 mg first then use 0.6 dose afterwards
If they are at stage 3 or higher, NO loading dose (just dose 0.6 mg dose)
What are considered 1st line for prophylaxis gout?
Colchicine and NSAIDs
- *Low-dose Glucocorticoids are also acceptable
- CANT use in CHF or CAD patients though
Epidemiology facts about hyperuricemia
Roughly 4% of the US has this
More common in males
Is defined as a serum uric acid level of >6.8mg/dL in men and >5.7mg/dL in women
20% of patients with gout/hyperuricemia also have stage 3 or greater CKD
In women, gout is far more likely after menopause due to estrogen having a uricosuric effect
What are the most common comorbidities seen with gout?
Hypertension (88%)
Diabetes (17%)
ischemic heart disease (22%)
CHF/CAD (4%)
Lifestyle modifications for gout
Weight loss
Limit red meats, wine, alcohol, fructose beverages
Give tart cherry juice
What is the most widely accepted first-line therapy for gout?
Xanthine oxidase inhibitors
- Allopurinol and febuxostat
What is AHS?
Allopurinol hypersensitivity syndrome
- characterized by rash/eosinophilia/leukocytosis/fever/hepatitis and progressive CKD
Risk factors:
- to high of a initial dose of Allopurinol
- patient has HLA-B*5801 allele
- first 6 months on Allopurinol
What two drugs that are not considered uricosuric agents can be off-labeled used a uricosuric agent?
Losartan and fenofibrate
losartan especially is commonly used as a uricosuric agent in CKD patients
fenofibrate CANT be used in patients taking statins since it increases rhabdomyolysis risks
