NHS Lothian haematology (in development)
Conversion to or from parenteral anticoagulants
Converting from apixaban to parenteral anticoagulants: Give the first dose of parenteral anticoagulant at the time the next apixaban dose would be taken.
Converting from parenteral anticoagulants to apixaban: Start apixaban 0-2 hours before the time of the next scheduled administration of the parenteral drug (e.g. LMWH) or at the time of discontinuation of a continuously administered parenteral drug (e.g. intravenous heparin).
Conversion to or from warfarin
Converting from apixaban to warfarin:
There is a potential for inadequate anticoagulation during the transition from apixaban to warfarin. Continuous adequate anticoagulation should be ensured during any transition to an alternative anticoagulant. It should be noted that apixaban may contribute to an elevated INR. When converting patients from apixaban to warfarin, continue administration of apixaban for at least 2 days after beginning warfarin. After 2 days of coadministration of apixaban with warfarin, obtain an INR prior to the next scheduled dose of apixaban. Continue coadministration of apixaban and warfarin until the INR is ≥2.0.
Converting from warfarin to apixaban:
Note that INR values will be falsely elevated following the intake of apixaban. The INR is not valid to measure the anticoagulant activity of apixaban and should not be used. When converting patients from warfarin therapy to apixaban, discontinue warfarin and start apixaban when international normalised ratio (INR) <2.0.
Dosing recommendations before and after invasive procedures and surgical intervention
Apixaban should be stopped at least 24 hours prior to interventions with a low risk of bleeding (this includes interventions for which any bleeding that occurs is expected to be minimal, non-critical in its location or easily controlled) if possible, and based on the clinical judgement of the physician. Apixaban should be discontinued at least 48 hours prior to elective surgery or invasive procedures with a moderate or high risk of bleeding. If thromboprophylaxis is indicated low[1]molecular-weight-heparin (LMWH) should be commenced at prophylactic doses, as per the LUHD Antithrombotic Guide http://intranet.lothian.scot.nhs.uk/NHSLothian/Healthcare/A-Z/Haematology/policy/Documents/Antithrombotic%20Guideline.pdf, and the first dose given at least 24 hours after the last dose of apixaban. Once post-operative haemostasis is secure, apixaban can be restarted 24 hours after the last dose of LMWH.
Note that in individuals with mild (creatinine clearance 51-80 ml/min), moderate (creatinine clearance 30-50 ml/min) and severe (creatinine clearance 15-29ml/min) renal impairment apixaban plasma concentrations are increased 16%, 29%, and 44% respectively with corresponding increases in overall inhibition of anti-factor Xa. Apixaban may need to be discontinued earlier in advance of surgery if there is renal impairment; the elimination of apixaban can be confirmed by checking apixaban levels, and requires discussion with the duty haematologist.
If the surgical/interventional procedure cannot be delayed there will be an increased risk of bleeding that should be assessed against the urgency of the intervention. Regional anaesthesia will be contra-indicated in such situations.
Restarting apixaban after an invasive procedure will depend on the nature of the surgery or invasive procedure and whether the patient can take oral medications. Note that apixaban is rapidly absorbed with maximum concentrations appearing 3-4 hours after tablet ingestion. Patients are fully anticoagulated following a single dose of the drug. Discussion with on call haematology is advised if there is any doubt.