NOTE:
Also known as 6-MP.
For mercaptopurine use in the treatment of neoplastic disease see Chemotherapy drug record.
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 occur. Withhold mercaptopurine if renal function deteriorates in the post-operative period and contact patient’s specialist for advice.
Monitor liver function tests (LFTs) – see Interactions with other common medicines used in the perioperative period.
Interactions with common anaesthetic agents
None.
Interactions with other common medicines used in the perioperative period
Hepatotoxicity
See also 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 therapy. Discontinue if jaundice develops and contact patient’s specialist for advice.
Paracetamol
Both mercaptopurine and paracetamol increase the risk of hepatotoxicity. Whilst single perioperative doses of paracetamol should not pose a problem, continued post-operative treatment may require close monitoring of LFTs.
Antimicrobials
Hepatotoxicity
See also Hepatotoxicity above.
There is an increased risk of hepatotoxicity when mercaptopurine is used in combination with the following:
- clavulanic acid (found in co-amoxiclav)
- doxycycline
- flucloxacillin
Myelosuppression
Concomitant use of mercaptopurine with the following can increase the risk of myelosuppression:
- 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
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]
Kumar A, Auron M, Aneja A et al. Inflammatory Bowel Disease: Perioperative Pharmacological Considerations. Mayo Clin Proc. 2011; 86(8):748-757
Joint Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 23rd June 2019]
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]
Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 24th June 2019]