MSK (Xanthine Oxidase Inhibitors)

Question 1

Examples of drug (Xanthine Oxidase Inhibitors)

Answer 1

• Allopurinol

Question 2

Mechanism of action (Xanthine Oxidase Inhibitors)

Answer 2

• Reduces synthesis of uric acid by competitively inhibiting xanthine oxidase.
• Reduces serum uric acid level

Question 3

Indications (Xanthine Oxidase Inhibitors)

Answer 3

• Prophylaxis of gout
• Prophylaxis of calcium oxalate renal stones
• Hyperuricaemia associated with cancer chemotherapy

Question 4

Side effects (Xanthine Oxidase Inhibitors)

Answer 4

• Rash
• Hypersensitivity
• Gastrointestinal disturbances
• Neutropenia (rare)

Question 5

Important pharmacokinetics/pharmacodynamics (Xanthine Oxidase Inhibitors)

Answer 5

• Not used to treat acute attack of gout, can exacerbate the inflammation, so should not be started during acute episodes.
• Cytochrome P450 enzyme inhibitor
• Azathioprine metabolism affected.

Question 6

Patient information (Xanthine Oxidase Inhibitors)

Answer 6

• Rash and abdominal disturbances are relatively common.
• Rash should be reported to a doctor
• Keep taking allopurinol, even when there is no sign of gout.
• In order to prevent an exacerbation of gout a NSAID or cochicine is often prescribed for the first 3 months of therapy