Azathioprine

Question 1

What is Azathioprine metabolised into ?

Answer 1

Mercaptopurine

Question 2

Azathioprine and allopurinol

Answer 2

Dose of azathioprine should be reduced when also taking allopurinol due to risk of bone marrow suppression

Question 3

SE of Azathioprine

Answer 3

• N+V (usually resolves within a few weeks but if not divided the dose and take after food)
• Hypersensitivity (withdraw if occurs)
• Neutropenia + Thrombocytopenia (dose dependent)

Question 4

Azathioprine and pregnancy

Answer 4

Reports of premature birth and low birth weight in particular when combined with corticosteroids
Spontaneous abortion following maternal/paternal exposure

Question 5

Azathioprine monitoring requirements

Answer 5

FBC weekly for 4 weeks, then every 3 months
Blood tests and monitoring for signs of myelosuppresion in the long term

Question 6

Pre-treatment screening for azathioprine

Answer 6

TPMT metabolises this drug. Increased risk of myelosuppresion in patients with reduced enzyme activity. Patients with absent activity should not receive the drug