Prescribing apixaban

Acute Oncology Guidelines
NHS Lothian

Apixaban is the direct oral anticoagulant (DOAC) of choice on the Lothian Joint Formulary for the treatment of VTE in patients with an active malignancy. Patients should be commenced on apixaban 10mg bd at the time of VTE diagnosis, with dose reduced to 5mg bd after 7 days.

Patients should receive a minimum of 6 months of apixaban. If the patient’s cancer is not cured, or they continue to receive SACT, continuing anticoagulation indefinitely can be considered after assessment of the risk-benefit ratio of continuing apixaban therapy4. If anticoagulation is desired beyond 6 months, apixaban dose should be reduced to 2.5mg bd. The EVE trial is recruiting to evaluate bleeding risk in cancer patients treated beyond 6 months with apixaban21. 

No dose adjustments are required for body weight or age. See table below for recommendations in renal or hepatic impairment. Concurrent use of drugs that strongly affect the CYP3A4 enzyme and/or P-glycoprotein can alter plasma concentrations of apixaban.  Some of these interactions are detailed in the table below and Appendix 2 – for comprehensive up to date listings of drug-drug interactions, refer to the most recent edition of the BNF.  

Note that apixaban doses for the treatment of VTE differ from those used as thromboprophylaxis in non-valvular AF, and from those used as thromboprophylaxis during SACT.

Investigations for patients starting/receiving apixaban

  • Patients should have a baseline FBC, PT and APTT, UEs and LFTs performed.   
  • Routine monitoring is not required given apixaban’s specificity, predictability, and wide therapeutic index.  
  • A coagulation screen has not been validated for assessing the degree of anticoagulation in patients taking DOACs and should not be used for this purpose.   
  • DOACs can prolong the PT and APTT, but a normal coagulation screen does not guarantee normal haemostasis in patients using a DOAC.   
  • Platelet count, fibrinogen and thrombin time are unaffected by DOAC use.   

All patients must be counselled carefully at the time of commencing therapy with apixaban, with assessment of the benefits of treating VTE compared to the risk of bleeding. Please adhere to the guidance given at the following link, (only accessible when connected to intranet) use the counselling sheet to document discussions held with the patient and send a letter to the GP requesting ongoing prescription.

Do not administer apixaban when:

  • platelets <50 x109/L; anticipated platelet decrease to <50 x109/L due to disease or treatment 
  • haemorrhagic disorder 
  • coagulopathy 
  • recent CNS surgery  
  • uncontrolled severe hypertension (BP >180/100mmHg despite treatment)  
  • active bleeding site or major bleeding event in last 2 months.

Guidance on the interpretation of laboratory tests in the presence of DOACs, peri-operative advice for patients on DOACs and the management of bleeding in patients on DOACs can be found on the Healthcare A-Z, Haematology, policies intranet web page (only accessible when connected to intranet) and are updated annually. 

Summary guide for apixaban dosing for treatment of VTE

Summary guide for apixaban dosing for treatment of VTE8
Recommended dose

10mg twice daily for 7 days 

then 5mg twice daily for 6 months
Consider dose reduction to 2.5mg twice daily if continuing anti-coagulation beyond 6 months
Special circumstances:
Renal impairment CrCl<30ml/min Apixaban not recommended
Hepatic impairment Child-Pugh A, B

No dose modification

Use with caution

Child-Pugh C cirrhosis

Coagulopathy (PT ration or APTT ratio >1.5)

AST/ALT > 2 xULN

Bilirubin > 1.5xULN

 Apixaban not recommended
Safety of apixaban has not been established in patients with an AST/ALT > 2xULN or bilirubin >1.5xULN
Strong inhibitors of both CYP 3A4 & P-gp ketoconazole, itraconazole, voriconazole, posaconazole, ritonavir

Safety may be reduced.

Apixaban not recommended.
Strong inducers of both CYP 3A4 & P-gp rifampicin, phenytoin, carbamazepine, phenobarbital, St John's Wort

Efficacy may be reduced.

Apixaban not recommended.
Cerebral metastases; primary brain tumour Discuss with patient's consultant.

 

Child-Turcotte-Pugh score for assessment of liver function in cirrhotic patients

Parameter Points
1 2 3
Bilirubin <34 34-50 >50
Albumin >35 28-35 <28
INR <1.7 1.7-2.3 >2.3
Ascites None Mild/diuretic responsive Severe/diuretic refactory
Encephalopathy None Mild (grade 1 or 2) Severe (grade 3 or 4)
Score: Child's A 5-6; Child's B 7-8; Child's C 9-15

Editorial Information

Last reviewed: 01/12/2021

Next review date: 01/12/2024

Author(s): Dalrymple H.

Version: 2.1

Approved By: CTAC Chair

Reviewer name(s): Stewart J.