Western Locality Shared care information ~ Azathioprine and Mercaptopurine

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1 The following guidelines are currently under review. In the interim, the guidelines remain valid; if GPs have any specific concerns or questions, they should seek advice from the specialist with whom they have agreed to share care. Western Locality Shared care information ~ and Aim of treatment (other conditions) April 2013 is widely used for transplant recipients and it is also used to treat a number of autoimmune conditions, usually when corticosteroid therapy alone provides inadequate control., a metabolite of azathioprine, is an antimetabolite used as maintenance therapy for acute leukaemias and in the management of ulcerative colitits and Crohn s disease (unlicensed indication). It is often prescribed for patients whose disease flares up either as the dose of steroid is reduced or within weeks of stopping steroid, or for patients who require more than two courses of steroids a year. Due to their relatively slow onset of action, benefits may not be observed for 3 months. Indications for the purposes of this guideline This information is for patients receiving treatment under the care of: Gastroenterology Haematology Renal For Rheumatology and dermatology patients refer to the appropriate guidelines. Specialist responsibilities 1. To assess full blood count (including platelets), renal and liver function and erythrocyte sedimentation rate or C reactive protein before starting treatment. Suggest checking TPMT levels before prescribing; approximately 1:300 people will be deficient. FBCs should be performed weekly for the first 8 weeks of treatment and 2 weeks after each dose increase. LFTs should be monitored weekly for the first 4 weeks of treatment with mercaptopurine only. It may be more convenient for the patient to have weekly blood tests carried out in the GPs surgery. 2. To initiate treatment and supply patient with monitoring booklet. 3. Prompt verbal communication followed up in writing to GP of changes in treatment or monitoring requirements, results of monitoring, assessment of adverse events or when to stop treatment. Urgent changes to treatment should be communicated by telephone to GP 4. To periodically review the patient. General practitioner responsibilities If GP has agreed to share care: 1. To monitor the patient s overall health and well-being 2. To carry out appropriate monitoring (see below) 3. To prescribe treatment 4. To monitor side effects of treatment, and seek urgent advise as necessary. 5. To contact the appropriate secondary care physician as appropriate

2 Monitoring during treatment: general practice Patients must report immediately any evidence of infection, unexpected bruising/bleeding or other manifestations of bone marrow suppression. The following tests must be performed at the required frequency: Full Blood count (including platelets) Weekly for the first 8 weeks, in collaboration with specialist At 1-3 monthly intervals ~ more often in hepatic and renal insufficiency Liver Function Test (For the use of mercaptopurine in the treatment of acute leukaemia, refer to specialist advice and the product s SPC) Weekly for the first 4 weeks, in collaboration with specialist 3 monthly in hepatic impairment, otherwise 6 monthly. Results/symptoms and actions to be taken WBC Test/symptom Result Action <3.5x109/L Withhold drug and discuss with specialist Neutrophils <2x109/L Withhold drug and discuss with specialist Platelets AST, ALT or Alk. Phos Rash or oral ulceration MCV Abnormal bruising or sore throat <150x109/L Withhold drug and discuss with specialist >2-fold rise Withhold drug and discuss with specialist >108fl* Withhold drug and discuss with specialist Investigate and if B12 or folate low, start appropriate supplementation Withhold until FBC result available * MCV threshold updated due to change in local lab reported normal values; if blood samples are not being analysed by Derriford Hospital lab, confirm threshold for action with specialist. (February 2018) Back-up advice and support Gastroenterology Dr C Hayward Dr S Cochrane Dr S Dunlop Dr A Latchford Dr S Lewis Dr M Metzner Haematology Dr J Copplestone Dr M Hamon Dr A Prentice Dr S Rule Dr T Nokes Dr H Hunter Dr D W Thomas Renal Dr P Rowe Dr R McGonigle

3 Dr W Tse Dr I Saif Dr H Cramp Derriford Medicines Information: Medicines Optimisation Teams NEW Devon CCG, Western Locality Kernow CCG

4 Supporting Information This guideline highlights significant prescribing issues, not all prescribing information and potential adverse effects are listed. Please refer to SPC/data sheet for full prescribing data. Preparations Available as tablets containing 25mg and 50mg azathioprine Unlicensed 10mg capsules are available on a named patient basis injections should not be prescribed or administered within primary care Available as a tablet containing 50mg mercaptopurine. Dose Transplantation adults and children A dose of up to 5mg/kg body weight/day may be given on the first day of therapy. Maintenance dose should range from 1 to 4mg/kg body weight/day and must be adjusted according to clinical requirements and haematological tolerance. Dosage in other conditions adults and children In general, starting dose is from 1 to 3mg/kg body weight/day, and should be adjusted, within these limits, depending on the clinical response (which may not be evident for weeks or months) and haematological tolerance. Acute leukaemia: initially 2.5mg/kg daily Ulcerative colitis and Crohn s disease: Maintenance dose 1mg 1.5mg/kg daily [Guidelines for the management of inflammatory bowel disease in adults, British Society of Gastroenterology.] Contraindications Hypersensitivity to azathioprine / mercaptopurine Pregnancy Cautions Hepatic impairment ~ reduce dose if hepatic or haematological toxicity occurs Renal insufficiency ~ use doses at the lower end of normal range; haematological response should be carefully monitored Elderly ~ reduce dose and monitor for toxicity throughout treatment Hepatic impairment ~ may need to reduce dose Renal insufficiency ~ reduce dose for those patients with moderate to severe renal impairment (GFR <10ml/minute; serum creatinine >300micromol/litre 4

5 Side effects (Refer to SPCs for further information) Bone Marrow Suppression Patients should be warned to report immediately any signs or symptoms of bone marrow suppression e.g. inexplicable bruising or bleeding, infection. Hypersensitivity reactions Liver impairment Dose-related bone marrow suppression Cholestatic jaundice Hair loss Increased susceptibility to infections Colitis in patients receiving corticosteroids Nausea Rarely: pancreatitis, pneumonitis, hepatic veno-occulsive disease Bone marrow suppression Hepatotoxicity Oral ulceration Pancreatitis Anorexia, nausea and vomiting have occasionally been noted Interactions (Refer to the BNF for further information) The following drugs have a potentially serious interaction with azathioprine and mercaptopurine, and caution must be used when prescribing concurrently: Rifampicin (azathioprine only) Sulfamethoxazole (as co-trimoxazole) Trimethoprim Warfarin Avoid concomitant use of azathioprine or mercaptopurine with: Allopurinol (Concomitant use of allopurinol with either azathioprine or mercaptopurine may be appropriate if supervised by an appropriate specialist). Clozapine 5

6 Shared Care Agreement Letter Consultant Request To: Dr Practice Address... Patient Name: NHS Number: Date of birth: Address: Diagnosed condition:. I recommend treatment with the following drug:.. At the following dosage:. I request your agreement to sharing the care of this patient according to the Western Locality Shared Care Information guidelines for this drug. The patient has been initiated on treatment and stabilised in accordance with the appropriate Shared Care Information. Principles of shared care: GPs are invited to participate, but if the GP is not confident to undertake these roles then they are under no obligation to do so. If so, the total clinical responsibility for the patient for the diagnosed condition remains with the specialist. If asked to prescribe this drug the GP should reply to this request as soon as practical. Sharing of care assumes communication between the specialist, GP and patient. The intention to share care should be explained to the patient and accepted by them. Remember: the doctor who prescribes the medication has the clinical and legal responsibility for the drug and the consequences of its use. Signed: Date: Consultant name: Telephone number: Fax number address Please sign below and return promptly. Remember to keep a copy of this letter for the patient s records. If this letter is not returned shared care for this patient will not commence. 6

7 GP Response I agree / do not agree* to share the care of this patient in accordance with the Shared Care Guideline. Signed:.. GP name:. Date:. *Delete as appropriate. 7