Blood-thinning drug’s guidelines may be flawed

Guidelines for doctors about a blood-thinning drug may be flawed, according to a British Medical Journal investigation published today.

It has raised concerns about the regulatory decisions that led to the approval of Pradaxa, favoured by patients because they do not have to undergo the regular blood tests needed with Warfarin.

According to the BMJ, drugmaker Boehringer Ingelheim holds documentary evidence that blood tests could reduce major bleeds among patients taking Pradaxa.

BMJ claimed neither doctors or regulators had ever been aware of these calculations.

The Health Products Regulatory Authority, formerly the Irish Medicines Board, said it was aware of the BMJ publication and was pursuing the matter.

The authority has received 82 reports of suspected adverse reactions associated with Pradaxa since 2012, but these were not unexpected.

Dabigatran, known as Pradaxa in Europe, Australia, and the US, is one of a number of oral anti-coagulants available in Ireland since 2008 which prevent strokes in patients with irregular heart rhythm.

It has been marketed as a better alternative to Warfarin because patients did not need tests to check if they have the right amount of the drug in their blood.

The main benefits of Pradaxa had been documented in a single clinical trial, called RE-LY.

According to the BMJ, regulators had concerns about the design and oversight of the trial.

In June 2012, a company analysis of the RE-LY data showed that measuring blood levels of the drug and adjusting the dose accordingly could reduce major bleeding by up to 30%-40% compared to Warfarin.

Boehringer Ingelheim argued the anti-clotting activity, or blood levels, did not need monitoring.

“Our scientists determined, and the FDA concurred, that the research does not support making dosage decisions based on plasma concentrations — a conclusion based solely on science and patient welfare,” a spokesperson told BMJ.

Irish Heart Foundation medical director Angie Brown said the IHF was concerned about the new information.

-Patients with concerns should check with their GP and prescriber or call the Irish Heart Foundation’s national helpline on 1890 432787.