Mercaptopurine monitoring

Published Last updated
Using this page · Individualise medicines monitoring

This medicines monitoring page has been written using publications and expert opinion. It is designed to save clinician time, but not replace professional responsibility. When using this page you should: ensure an individualised monitoring plan is developed in partnership with the patient and take account of any locally agreed advice and guidance.

Before starting

Required

  • Baseline
    • Full blood count
    • Liver function tests
    • Urea and electrolytes
    • TPMT assay
    • Serum creatinine (for creatinine clearance) or Estimated glomerular filtration rate

Consider

  • Baseline
    • Epstein Barr Virusconsider antivirals in acute infection
    • Hepatitis B
    • Hepatitis C
    • HIV
    • NUDT15 genotype
    • Varicella Zoster Virus Immunityif no history of infection; vaccinate if low

After started or dose changed

Consider

  • At week 2, 4, 8 and 12
    • Full blood count
    • Liver function tests
    • Serum creatinine (for creatinine clearance) or Estimated glomerular filtration rate
    • Urea and electrolytes

Ongoing once stable

Consider

  • Every 3 months
    • Full blood count
    • Liver function tests
    • Serum creatinine (for creatinine clearance) or Estimated glomerular filtration rate
    • Urea and electrolytes

Abnormal results

Be aware of trends in results and respond accordingly.

Respond to absolute levels

Consider stopping treatment and contacting a specialist if any of the following develop:

Full blood count

  • Albumin less than 30g/L
  • Neutrophils less than 2 x 109/L; if less than 1 x 109/L, consider antibiotics and possibly GCSF if febrile
  • Platelets less than 140 x 109/L
  • WCC less than 3.5 x 109/L
  • MCV greater than 105fL

Liver function

  • AST or ALT greater than 100units/mL

Clinical conditions

  • Pancreatitis develops
  • Patient develops skin or mucosal reaction (e.g. rash, pruritus, or throat ulceration), sore throat, fever, unexplained bruising or bleeding, nausea, vomiting diarrhoea or weight loss, diffuse alopecia, breathlessness, infection or cough, or peripheral neuropathy

Renal function

  • Creatinine increase greater than 30% above baseline over 12 months
  • Calculated GFR less than 60ml/min/1.73m2 (repeat in 1 week, if still more than 30% from baseline, withhold and discuss with specialist team)

Notes

Advice to patients

Advise patients to:

  • report immediately any signs or symptoms of bone marrow suppression (e.g. inexplicable bruising or bleeding)
  • report immediately any signs or symptoms of liver impairment (e.g. new onset jaundice)
  • protect skin from sun exposure (given possible increased risk of non-melanoma skin cancer)

Bibliography

Update history

  1. Link to BAD guideline updated.
  1. Published

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