Drugs used in Treatment of Gout and Rheumatoid Arthritis Flashcards
Recurrent acute inflammatory arthritis with red, tender, hot and swollen
joints
?
Gout
Uric acid, a product of purine metabolism, has low water solubility, especially at low pH. When blood levels are high, it precipitates and deposits in joints, especially the big toe, kidney and subcutaneous tissue called?
tophy
Types of gout ?
- Primary or hereditary gout :
- to genetic error in purine metabolism - Secondary gout:
due to drugs that
- Inhibit uric acid excretion
- Increase urate production by increasing rate of cell death (cancer chemotherapy)
Stages of Gout?
- Asymptomatic hyper-uricemia (serum uric acid higher than 6 mg/dl)
- Acute intermittent gout (attacks of gout or flares)
- Inter-critical stage (in between attacks)
- Chronic gout (deformities)
Non-pharmacological treatment of gout: ?
Try to lose weight and do physical exercises
Drink a lot of water (2-3 liters/day)
Avoid alcohol and smoking
Avoid drugs as salicylate and diuretics
Low purine diet (avoid red meat, sea products, dried fruits, beans,…)
Pharmacological treatment of gout ?
- Uricostatics (drugs that interfere with uric acid synthesis):
- Allopurinol
- Febuxostat - Uricosurics (drugs that increase uric acid excretion)
- Probenecid - Uricases (enzyme that breakdown uric acid):
- Pegloticase - Tubulin inhibitors
- Colchicine - Anti-inflammatory drugs
- Non-steroidal anti-inflammatory drugs (NSAIDs) except salicylate
- Corticosteroids
Interfere with uric acid synthesis by inhibiting xanthine oxidase enzyme.
xanthine and hypoxanthine are more soluble, have a higher renal clearance
than that of uric acid
Type of drug?
Uricostatic drugs: Allopurinol
Uricostatic drugs: Allopurinol
Pharmacokinetics?
Converted by the liver to active metabolite alloxanthine (oxypurine)
Uricostatic drugs: Allopurinol
Uses?
- first choice drug in chronic gout:
(With long-term allopurinol therapy, tophi gradually disappear and nephropathy is halted, even reversed.) - Secondary hyperuricaemia : due to cancer chemotherapy/
radiation/thiazides or other drugs
Adverse effects of Uricostatic drugs: Allopurinol
uncommon.
- May induce acute attack of gout, Fever, rash, toxic epidermal necrolysis
Interfere with uric acid synthesis by inhibiting xanthine oxidase
enzyme.
Drug?
Uricostatic drugs: Febuxostat
Uricostatic drugs: Febuxostat
Uses?
- alternative drug for treating symptomatic gout only in patients intolerant to allopurinol, or in those with some contraindications.
Adverse effects Of Uricostatic drugs Febuxostat?
Liver damage: liver function needs to be monitored during
febuxostat therapy.
Like other drugs used to treat hyperuricaemia, NSAID/colchicine
cover should be provided for 1–2 months while initiating febuxostat therapy.
Inhibit Urate Transporters (URAT1) of renal proximal tubule,
preventing urate reabsorption
Drug?
Uricosurics: Probenecid
Uses of Uricosurics: Probenecid
- Chronic gout and hyperuricaemia: Probenecid is a second line/adjuvant drug to allopurinol.
- prolong penicillin or ampicillin action by
enhancing and sustaining their blood levels, e.g. in gonorrhoea.
Adverse effects of Uricosurics: Probenecid?
- May induce acute attack of gout
- Uric acid kidney stones
- Gastric irritation
Contraindications of Uricosurics: Probenecid?
- Acute gout
- Previous kidney stones or existing renal disease
- Elderly patients Caution in peptic ulcer disease
Recombinant mammalian uricase enzyme that convert urate to allantoin,
which is more soluble and easily excreted in urine
Drug?
Uricase enzyme: Pegloticase