antiproliferative immunosuppressants (azath,mercap)

Question 1

when are they usually used

Answer 1

• chronic inflammatory and autoimmune diseases
• organ transplant patients

Question 2

What is azathioprine metabolised to

Answer 2

mercaptopurine

Question 3

Reduce dose of azathioprine when given concomitantly with t his medicine due to risk of bone marrow suppression

Answer 3

allopurinol

Question 4

why does dose of azathioprine need to be reduced if pt is also taking allopurinol

Answer 4

reduces risk of bone marrow suppression

Question 5

This blood disorder has been reported with azathioprine & mycophenolate mofetil as a side effect

What to do if it occurs

Answer 5

red cell asplenia

dose reduction or discontinuation should be considered under specialist supervision

Question 6

Advise patients to report immediately any signs like infection, unexplained bruising, bleeding if they are on azathioprine. Why?

Answer 6

Bone marrow suppression

Question 7

Nausea, vomiting and diarrhoea may occur during early stages of treatment. Treatment can be discontinued if this occurs in the following autoimmune disease

Answer 7

RA

Question 8

Hypersensitivity reactions for azathioprine call for immediate withdrawal. Name some symptoms

Answer 8

malaise,
dizziness, vomiting, diarrhoea, fever, rigors, myalgia,
arthralgia, rash, hypotension and interstitial
nephritis

Question 9

Monitoring for azathioprine

Answer 9

FBC for 4 weeks
then every 3 months
monitor for toxicity throughout
blood tests and monitoring for signs of myelosuppression in long term treatment

Question 10

pre treatment screening for azathioprine/mercapropurine

Answer 10

TPMT metabolises the thiopurines
risk of myelosuppression is INCREASED in ptt with reduced activity of TPMT
therefore measure TPMT activity BEFORE starting

Question 11

What enzyme metabolises thiopurines

Answer 11

Thiopurine methyltransferase (TPMT)

Question 12

why do pt need to have their thiopurine methyltransferase (TPMT) activity measured before starting azathioprine or
mercaptopurine?

Answer 12

TPMT metabolises
thiopurine drugs (azathioprine, mercaptopurine); the
risk of myelosuppression is increased in patients with
reduced activity of the enzyme.
Patients with absent TPMT activity
should not receive thiopurine drugs; those with
reduced TPMT activity need specialist supervision.