Mercaptopurine (6-Mercaptopurine)


 

[For mercaptopurine use in the treatment of neoplastic disease see Statement on Chemotherapy]


  Issues for Surgery


Risk of perioperative flare in disease activity if omitted.

Risk of post-operative infection if continued.


  Advice in the Perioperative period


Elective and Emergency Surgery

Continue.

Post-operative Advice

Monitor the patient for signs of infection – consider withholding mercaptopurine if a patient develops a significant systemic infection and contact patient’s specialist for advice.

Close monitoring of renal function is important so that inadvertent drug accumulation does not occur1, 2. Withhold mercaptopurine if renal function deteriorates in the post-operative period2 and contact patient’s specialist for advice.

Monitor liver function tests (LFTs) – see under Interaction(s) with other Common Medicines used in the Perioperative Period


  Interaction(s) with Common Anaesthetic Agents


None1, 3, 4, 5.


  Interaction(s) with other Common Medicines used in the Perioperative Period


Hepatotoxicity (also see under Antimicrobials below)

Mercaptopurine is hepatotoxic and liver function tests (LFTs) should be monitored weekly during treatment – more frequent monitoring may be advisable in those receiving potentially hepatotoxic therapy1, 4. Discontinue if jaundice develops and contact patient’s specialist for advice2.

Paracetamol
Both mercaptopurine and paracetamol increase the risk of hepatotoxicity3. Whilst single perioperative doses of paracetamol should not pose a problem, continued post-operative treatment may require close monitoring of LFTs.

Antimicrobials

Hepatotoxicity (also see above under Hepatotoxicity)
There is an increased risk of hepatotoxicity when mercaptopurine is used in combination with the following3: -

  • clavulanic acid (found in co-amoxiclav)
  • doxycycline
  • flucloxacillin

Myelosuppression
Concomitant use of mercaptopurine with the following can increase the risk of myelosuppression3, 4: -

  • co-trimoxazole
  • linezolid
  • trimethoprim

Whilst single surgical prophylactic doses should not pose a problem, continued post-operative treatment may require close monitoring of LFTs and / or haematological abnormalities. Consult current product literature.


  Further Information

 

None relevant.

 

  References


  1. Mercaptopurine. In: Brayfield A (Ed), Martindale: The Complete Drug Reference. London: The Royal Pharmaceutical Society of Great Britain. http://www.medicinescomplete.com [Accessed 24th June 2019]
  2. Kumar A, Auron M, Aneja A et al. Inflammatory Bowel Disease: Perioperative Pharmacological Considerations. Mayo Clin Proc. 2011; 86(8):748-757
  3. Joint Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 23rd June 2019]
  4. Summary of Product Characteristics – Mercaptopurine 50mg tablets. Aspen. Accessed via www.medicines.org.uk 24/06/2019 [date of revision of the text December 2018]
  5. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 24th June 2019]