Prescribing Notes
- Refer to NICE NG158 guidance on anticoagulation treatment for venous thromboembolism. Choice of anticoagulant depends on co-morbidities / clinical features.
- Apixaban or rivaroxaban are recommended first line in patients with no relevant co-morbidities or significant clinical features.
- Please note differing initial dose periods and dosing schedules; dose adjustment may be needed. Refer to BNF and CKS.
- Indication and duration of treatment should be clearly recorded at initiation of treatment; the patient-held anticoagulant treatment booklet should be used. See BNF for details.
- Estimated glomerular filtration rate (eGFR) can overestimate renal function and increase the risk of bleeding events. Creatinine clearance (CrCl) should be calculated using the Cockcroft-Gault formula to determine dosage adjustments for DOACs. Refer to BNF for dosage adjustments in renal impairment. Do not use DOACs if CrCl is < 15ml/min (<30ml/min for dabigatran):
- CrCl calculators embedded within GP IT systems do not give a reliable estimate of CrCl and are not recommended
- The use of a web based application such as MDCalc is suggested where actual bodyweight is used to calculate the CG CrCl.
- Renal function should be monitored at initiation and at least annually for patients taking DOACs. Ensure any necessary dose reductions are made.
- The anticoagulant effect of DOACs fades rapidly 12 to 24 hours after the last intake. Therefore strict compliance by the patient is crucial for adequate protection. Refer to individual SPC for ‘missed dose’ guidance for each DOAC.
- Clinical Knowledge Summaries provide a comprehensive overview in relation to oral anticoagulation and includes information that patients should be given prior to treatment and monitoring that should be carried out. Information on switching between anticoagulant regimens is also included.
- Patients should be warned of the hazards of treatment with anticoagulants. In particular, they should be aware of the need to report symptoms such as bruising. Patients should be provided with safety netting advice on signs of clinically relevant bleeding or clotting (e.g. FAST mnemonic) and when it is important to represent to hospital.
- Anticoagulant alert cards must be carried by patients and can be ordered by e-mailing the HSC Business Services Organisation at the following address pharmacystationeryorders@hscni.net.
- Dabigatran capsules cannot be crushed or opened and cannot be used in standard compliance aids due to the instability of the drug.
- Rivaroxaban must be taken with food. The MHRA has received a small number of reports suggesting a lack of efficacy (thromboembolic events) in people taking 15 mg or 20 mg rivaroxaban tablets on an empty stomach.
Cautions
- The MHRA reminds healthcare professionals of the bleeding risk with DOACs and of the importance that patients receive an appropriate dose based on renal function.
- Guidance on the management of dental patients taking anticoagulants or antiplatelet drugs by the Scottish Dental Clinical Effectiveness Programme (SDECP) has been adopted for use in Northern Ireland and is available at sdcep.org.uk.
- Specialist haematological advice should be sought regarding strategies for the reversal of the anticoagulant effects of DOACs.
- Specific reversal agents for dabigatran (idarucizumab) and the factor Xa inhibitors apixaban and rivaroxaban (andexanet alfa▼) are now available. These are for hospital only use – see Managed Entry Decisions for further details on when they can be used. A specific anticoagulant reversal agent for edoxaban is not available.
- Refer to BNF for full details of cautions, contraindications and interactions.