National Poisons Information Service

A service commissioned by Public Health England




Members of the public

seeking specific

information on poisons

should contact:


In England and Wales:

NHS 111 - dial 111


In Scotland:

NHS 24 - dial 111


In N Ireland:

Contact your local GP or

pharmacist during

normal hours; click here

(www.gpoutofhours for GP

services Out-of-Hours.


In Republic of Ireland:

01 809 2166



professionals seeking

poisons information

should consult:

Oral anticoagulants

Patients with a venous thromboembolism or at an increased risk of stroke from cardiac arrhythmia, especially atrial fibrillation, may require long-term treatment with an anticoagulant. Previously anticoagulation has been achieved using medicines which antagonise vitamin K-dependent clotting factors, such as warfarin. Warfarin use is complicated by its narrow therapeutic range, extensive drug interactions and a requirement for routine monitoring with blood tests. In overdose, however, the antidote vitamin K is available to reverse their effects. Recently, the use of directly-acting anticoagulants (DOACs, e.g. apixaban, dabigatran, edoxaban and rivaroxaban) has been increasing. These do not require regular drug monitoring, although antidotes are not readily available for all in the event of overdose.  


This year saw an increase in the numbers of NPIS telephone enquiries received about oral anticoagulants (438 this year, compared with 410 in 2016/2017). This arose because the increase in enquiries about DOACs (325 this year, from 286 in 2016/2017) exceeded the fall in enquiries about warfarin (103 this year, from 124 in 2016/2017) (Figure 6.6.1). Enquiries concerning DOACs are now more than three times as common as those involving warfarin. Enquiries concerning rivaroxaban and apixaban are received more commonly than those involving dagibatran and edoxaban (Figure 6.6.2) and may reflect prescribing practice. 


Most enquiries concerned patients who were asymptomatic, but there is a risk of adverse health outcomes so the NPIS will continue to monitor the pattern of enquiries concerning oral anticoagulants.


Figure 1. NPIS telephone enquiries about anticoagulants




Figure 2. NPIS telephone enquiries about directly-acting anticoagulants




Information from the NPIS Annual Report 2017/18.


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