Will this new drug replace warfarin?
QWill we still be monitoring anticoagulants in five years' time?
AXimelagatran, an oral direct thrombin inhibitor, has been through a series of clinical trials and is likely to be licensed in the UK soon. Prescribed as a fixed dose to be taken twice daily, ximelagatran will not require monitoring. But will it replace warfarin?
Trials have shown a similar bleeding rate between warfarin and ximelagatran, so it is not without risk.
Furthermore, 6 per cent
of patients have had their alanine aminotransferase liver enzyme level increased by more than a factor of two in the first few months of taking ximelagatran, so LFTs may need to be monitored in all patients initially.
There is no clotting test yet available to monitor the degree of anticoagulation achieved with ximelagatran. This will be a problem where an overdose has been taken because there is no antidote.
This will not be an issue generally as the half-life is short, but it could present difficulties in patients with renal impairment as ximelagatran is renally excreted.
So will we still have anticoagulant clinics checking INRs in five years' time? Despite all the caveats, clinical trials suggest ximelagatran will be a safe and effective drug for many patients currently taking warfarin. The initial cost will influence early prescribing.
I suspect many patients will change to ximelagatran, but some, such as those with artificial heart valves, will remain on warfarin.
In the meantime, studies have shown that with careful patient selection and training a substantial number are competent to monitor their own INR at home. Those who go on to learn self-dosing perform as well as professionals.
Dr Caroline Shiach is
consultant haematologist at Manchester Royal Infirmary