MERCAPTOPURINE (Adults)

Transcription

1 Shared Care Guideline DRUG: Introduction: MERCAPTOPURINE (Adults) Indication: Disease modifying drug for Crohn s disease and ulcerative colitis. Mercaptopurine is usually used in patients who cannot tolerate azathioprine due to side effects. Licensing Information: The above are unlicensed indications. Formulations: Tablets of 50mg Dosage & administration: Doses are initiated at 0.5mg/kg/day (to the nearest 25mg) and increased slowly at 4-6 week intervals. Doses may adjusted up to mg/kg/day according to patient response and side effects. Contraindications & Warnings: Azathioprine-induced pancreatitis or severe immunosuppression. Azathioprine hypersensitivity use with caution as there may be cross sensitivity between mercaptopurine and azathioprine. A trial of mercaptopurine may be considered appropriate. TPMT (thiopurine methyltransferase) deficiency. Serious infection. Caution: moderate to severe renal insufficiency or impaired liver function. Impaired bone marrow function Considered safe in pregnancy when benefits of treatment outweigh risks of untreated disease. Normal recommendation however is to advise on appropriate contraception in men and women of child bearing potential (as per the manufacturer's recommendations) and discuss any planned pregnancy with the specialist. If unplanned pregnancy occurs continue mercaptopurine and discuss with the specialist. Breast feeding the manufacturer advises women should not breast feed. Please consult specialist in cases of breastfeeding Live attenuated vaccines should be avoided. There may be a reduced response to other vaccines given. Interactions: Allopurinol Avoid if possible. If co-administration of allopurinol is necessary this should ONLY be after consultant initiation and the dose of mercaptopurine should be reduced to one quarter of the original dose with weekly blood monitoring. Febuxostat may increase mercaptopurine levels Warfarin - Closely monitor INR. Live vaccines - Avoid. Name: Mercaptopurine Shared Care Guideline Page 1 of 5

2 Co-trimoxazole (Septrin), trimethoprim, captopril (and possibly other ACE inhibitors) Co-administration of cytostatic or myelosuppressive drugs should be avoided. Co-prescribing of sulfasalazine, mesalazine or olsalazine should be under specialist advice only as increased risk of haematological toxicity. For full list see BNF or SPC at Adverse Effects: In general side effects are considered to be dose related and most will resolve on reduction of mercaptopurine dose or on cessation of treatment. Common Leucopenia, thrombocytopenia, raised transaminases, hepatotoxicity GP to be alert to any oral ulcerations, sore throat, unexplained rash or abnormal bruising or bleeding. Pancreatitis (common in patients with inflammatory bowel disease) Uncommon Nausea (relieved by taking tablets after meals), hypersensitivity, cholestatic jaundice, alopecia, rash and anaemia Very Rare Intestinal ulceration, haematological malignancies (mercaptopurine is mutagenic and carcinogenic). For full list see SPC at of the specialist initiating treatment: General: To assess the suitability of the patient for treatment. As per national, regional and local guidelines, to ensure that the patient/carer has received counselling and understands the therapy, its benefits, limitations, continued monitoring (where applicable), adverse effects, and is aware of actions to take if adverse effects are suspected. Go through patient information leaflet with patient. Inform patients of the long term monitoring requirements and provide a monitoring booklet. Inform the GP of the information provided to the patient. To review the patient as agreed intervals and copy all relevant results to the GP Carry out disease and initial drug monitoring as listed below. Formally hand over to GP by letter and patient informed - send a copy (either electronically or paper copy) of the Shared Care Guideline to the GP and ask whether they are willing to participate in shared care. Prescribing : Issue all prescriptions for 8 weeks minimum until patient is safely established on mercaptopurine and specialist team are satisfied that it is appropriate to share care. Name: Mercaptopurine Shared Care Guideline Page 2 of 5

3 Disease & drug monitoring: Monitor bloods according to schedule: TPMT (thiopurine methyltransferase) At baseline prior to commencing treatment Every 1 to 2 weeks for the first 8 weeks at clinical discretion whilst under secondary care and then as advised by specialist team (see responsibilities of GPs- monitoring). (Note weekly monitoring if allopurinol coadministered) of other prescribers: Discuss shared care arrangement with patient. Support and advise GPs as required. Assess response to treatment and initiate any dose changes as clinically appropriate including discontinuation of treatment. General and Prescribing: To reply to the request for shared care within 2 weeks of receipt of the Consultant letter. Monitor and prescribe as recommended by the specialist. Ensure continued prescribing of mercaptopurine remains clinically appropriate at dose advised by initiating team. The GP will typically be asked to take up monitoring and prescribing of mercaptopurine 8 weeks after treatment has been initiated. Notify Consultant if treatment with mercaptopurine is discontinued. Ensure there are no drug interactions with any other medications initiated in primary care (Note: Avoid live vaccines). Disease & drug monitoring: Carry out drug monitoring as listed and communicate abnormal results to the Specialist. Urgent drug discontinuation/ referral to specialist as clinically appropriate To stop treatment on the advice of the specialist. To refer back to the Specialist if the patient s condition deteriorates. Identify adverse effects to mercaptopurine and report these to the Specialist and where appropriate to the Commission on Human Medicines/MHRA (Yellow card scheme). Unless otherwise stated by the secondary care Specialist, apply the following monitoring frequencies following handover from secondary care: After handover from the specialist Monthly for 4 months then every 3 months (unless dose changed see below or abnormal blood results) (Note weekly monitoring if allopurinol coadministered) On dose increase by hospital, GP to temporarily increase monitoring to week 2,4,8 and then if stable resume previous monitoring regimen unless informed otherwise by initial prescriber Name: Mercaptopurine Shared Care Guideline Page 3 of 5

4 At consultations Ask about oral ulceration, unexplained bruising/bleeding, rash, sore throat of the Patient / Carer: Discontinue mercaptopurine and seek advice from initiating team if: WCC: <3.5 Neutrophils: <2.0 Platelets: <150 AST or ALT: >3 times the normal range Mouth or throat ulceration Unexplained bruising or bleeding Fever, nausea, vomiting or diarrhoea Diffuse alopecia Jaundice Summary: Report any possible side effects to their GP in particular potential signs and symptoms of bone marrow suppression (e.g. unexplained bruising, bleeding, sore throat, infection etc). Practice safe exposure to the sun Ensure they have adequate supply of medication. Attend appointments and take along monitoring book. Ensure appropriate contraception. Avoid breast feeding, unless discussed and agreed with specialist Inform GP urgently if unexpected pregnancy is suspected Disease & drug monitoring: As above contact GP or initiating team if side effects develop (see adverse effects) and attend appointments including those for routine blood tests/investigations Communication: Specialist to GP: The specialist will inform the GP when they have initiated mercaptopurine and when there are any subsequent changes in treatment standard clinic letter. Send a copy (either electronically or paper copy) of the Shared Care Guideline to the GP and ask whether they are willing to participate in shared care. Inform the GP of the information provided to the patient GP to Specialist: To reply to the request for shared care within 2 weeks of receipt of the Consultant letter. Irrespective of whether you accept prescribing responsibility or not, you should inform the consultant of relevant medical information regarding the patient and changes to the patient s medication regime irrespective of indication. Notify Consultant if treatment with mercaptopurine is discontinued. Name: Mercaptopurine Shared Care Guideline Page 4 of 5

5 Contact names & details: If you have any concerns regarding individual patients, see consultant letter for medical contact details or contact one of the following: Name Title/Location Telephone / Bleep / Gastroenterology York Gastroenterology Scarborough General surgery Scarborough IBD Specialist Nurse Drs Robins and Kelly Drs Turnbull and Turvill Drs Smale and Millson Drs Mitchell and Saraj Dr A Muddu Prof J Macfie Miss C McNaught Costs: Drug Tariff Oct 2012 Mercaptopurine 50mg x 25 = References: Yorkshire Regional Guidelines on the Monitoring of Adult Patients on Disease Modifying Drugs (DMARDS) Including Biologic Therapies. 5 th Edition. March 2009 BNF 66 Puri-Nethol SPC accessed on 20 th January 2014 Document Control: This information is not inclusive of all prescribing information and potential adverse effects. Please refer to the SPC (data sheet) or BNF for further prescribing information. The original Microsoft Word file of this document is located on: York Teaching Hospital NHS Foundation Trust Pharmacy Department X:\MEDICINES INFORMATION\Shared Care Guidelines\Approved Shared Care Guidelines\MERCAPTOPURINE Shared Care Guideline V1.1 Shared Care Guidelines are also available electronically via Prepared by: Checked by: Version: Dimah Sweis / Vikki Furneaux Jane Crewe / Stuart Parkes (Pharmacy YH) Clair Ranns (Pharmacist NY and Humber Commissioning Support Unit) 1.1 (Updated February 2014 to ammend information relating to use in pregnancy, disease and drug monitoring tests, and exposure to sun.) Date of Issue / Review: January 2014 (Updated February 2014) Date for next Review: January 2016 Approved by: Drug & Therapeutics Committee, January 2014 Name: Mercaptopurine Shared Care Guideline Page 5 of 5