Published: 2 June 2016

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Update: Oral Anticoagulants and Gastrointestinal Bleeding

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Prescriber Update 37(2): 23
June 2016

Warfarin, dabigatran and rivaroxaban are the three oral anticoagulants currently funded for use in New Zealand. Apixaban is also approved but is not currently funded.

The new oral anticoagulants (dabigatran, rivaroxaban and apixaban) all have a reduced risk of causing intracranial haemorrhage compared to warfarin¹.

The risk of gastrointestinal (GI) bleeding associated with the new oral anticoagulants remains unclear. Meta-analyses of randomised trials have identified higher rates of GI bleeding in patients taking dabigatran or rivaroxaban compared to those taking warfarin¹.

However, two recently published cohort studies found a similar risk of GI bleeding in patients taking dabigatran, rivaroxaban or warfarin^1,2. The results from these studies are summarised in Table 1. In addition to these, other observational studies have reported inconsistent results on the rates of GI bleeding in patients taking dabigatran compared to warfarin treatment².

As such, caution is advised when prescribing any oral anticoagulant to older people, particularly those over 75 years of age, and those at increased risk of bleeding¹.

Dabigatran can also cause GI symptoms (eg, dyspepsia). If GI symptoms develop, patients should be advised to take dabigatran with a meal and/or a proton pump inhibitor should be prescribed³. Similarly, for patients at risk of ulcerative GI disease, an appropriate prophylactic treatment may be considered when prescribing rivaroxaban, taking into consideration that the absorption of rivaroxaban can be affected by food⁴.

Patients should be informed about the signs and symptoms of GI bleeding and advised to seek immediate medical attention should they occur.

Table 1: Summary of adjusted hazard ratios of GI bleeding with dabigatran or rivaroxaban compared to warfarin

	Adjusted Hazard Ratios (95% Confidence Interval)
	Dabigatran vs Warfarin	Rivaroxaban vs Warfarin
Abraham et al1	Atrial fibrillation patients: 0.79 (0.61-1.03) Non-atrial fibrillation patients: 1.14 (0.54-2.39)	Atrial fibrillation patients: 0.93 (0.69-1.25) Non-atrial fibrillation patients: 0.89 (0.60-1.32)
Chang et al2	All patients: 1.21 (0.96-1.53)	All patients: 0.98 (0.36-2.69)

References

1. Abraham NS, Singh S, Alexander GC, et al. 2015. Comparative risk of gastrointestinal bleeding with dabigatran, rivaroxaban, and warfarin: population based cohort study. BMJ 350: h1857.
2. Chang HY, Zhou M, Tang W, et al. 2015. Risk of gastrointestinal bleeding associated with oral anticoagulants: population based retrospective cohort study. BMJ 350: h1585.
3. Boehringer Ingelheim New Zealand Limited. 2015. Pradaxa Data Sheet 4 December 2015. URL: www.medsafe.govt.nz/profs/datasheet/p/Pradaxacap.pdf (accessed 11 April 2016).
4. Bayer New Zealand Limited. 2015. Xarelto Data Sheet 19 November 2015. URL: www.medsafe.govt.nz/profs/datasheet/x/Xareltotab.pdf (accessed 11 April 2016).