Week 11 - Antigout and Uricosuric Agents Flashcards
Xanthine oxidase inhibitors: examples
- Allopurinol - first line
- Febuxostat
Allopurinol and Febuxostat: indications
Chronic gout
Xanthine oxidase inhibitors: MOA
Decrease uric acid levels by selectively inhibiting xanthine oxidase (enzyme responsible for conversion of hypoxanthine to xanthine to uric acid)
Uric acid then decreases, reducing risk of crystallization and gout attack
Inhibits inflammation
Xanthine oxidase inhibitors: caution and contraindications
- Caution in renal impairment
- Avoid use w/ azathioprine, mercaptopurine, theophylline
- Avoid in severe hepatic dysfunction
- Avoid in pregnancy
Which xanthine oxidase inhibitor can be used in pediatrics?
Allopurinol
- In children >6 years r/t hyperuricemia from cancer therapy
- Caution in lactation
Xanthine oxidase inhibitors: ADR
- Maculopapular skin rash
- Arthralgias
- N/D
- Elevated transaminases
Rare: hepatotoxicity
Hypersensitivity rash (higher in blacks, Asians, and hispanics)
Probenecid: indications
Chronic gout
NOT monotherapy
Probenecid: MOA
Increases excretion of serum uric acid by competitively inhibiting reabsorption of uric acid at proximal convoluted tubule
Sulfa based
Probenecid: ADR
- HA, dizziness, N/V
- Anorexia
- Gingival soreness
- Urinary frequency
- Dermatitis, pruritus
- Flushing fever
- Gout exacerbation
Rare: anaphylaxis, blood dyscrasias
Probenecid: caution and contraindications
- Patients w/ diagnosed blood dyscrasias
- Creatinine clearance is <30 mL/min
- Children <2 years
- Combination w/ ASA
- Patients w/ G6PD deficiency
- Pregnancy and lactation
- Sulfa allergy
Colchicine: indications
Acute gout flare
Colchicine: MOA
Inhibits activation, degranulation, and migration of neutrophils to area of a gout attack
Decreases inflammation and pain associated w/ gout attack (but NOT an analgesic)
Colchicine: caution and contraindications
- Combination w/ grapefruit juice
- Renal and hepatic impairment
- Elderly patients
- Pregnancy and lactation
Can colchicine be used in pediatrics?
Yes, if >16 years
Corticosteroids (prednisone): indications
Acute gout, RA
Corticosteroids (prednisone): MOA
Decreases inflammation by suppressing migration of polymorphonuclear leukocytes (neutophils, eosinophils, basophils) and reversing increased capillary permeability
Corticosteroids (prednisone): caution and contraindications
- Uncontrolled active infections
- Prolonged use may lead to adrenal suppression and immunosuppression
- Caution in diabetic patients and those w/ active GI disease
- Renal and hepatic impairment
- Pregnancy and lactation
Can corticosteroids (e.g. prednisone) be used in pediatrics to treat acute gout?
Yes
Corticosteroids (prednisone): ADR
- HTN
- Insomnia
- Mood changes
- Increased appetite
- Glucose intolerance
- Peptic ulcer (cutaneous atrophy, cataracts, glaucoma, osteoporosis, growth suppression, Cushing’s syndrome w/ chronic use)
Patient education about gout
- Increased HTN and cardiovascular risks are associated w/ higher uric acid levels
- DASH diet helps w/ gout
- Old gout diets NOT supported by evidence
- Fluid intake is key
True/False: Patients w/ gout should also take anti-inflammatory agents (indocin) and steroids
True
Can gout medications be used in pregnancy and pediatrics?
- ONLY probenecid can be used in pregnancy
- Not used in children except for uricemia of malignancy
True/False: When taking gout medications, it will be important to consider that uric acid crystals, when mobilized, can precipitate renal stones
True
What are general common side effects seen with gout medications?
GI disturbances and peptic ulcers
Colchicine: ADR
- Myopathy
- Weakness
- Neuropathy
- Malabsorption of B12
Geriatric gout medication considerations
Uric acid more toxic in older adults
- Drug of choice: probenecid
- Allopurinol can be used for renal impairment
- Toxic when combined w/ thiazides
What are off-label uses of colchicines?
Pericarditis
Scleroderma
