Australia issues bleeding warning for dabigatran
MedWire News: Australia's regulatory authority for therapeutic goods, the Therapeutic Goods Administration (TGA), has issued a safety advisory for the oral anticoagulant dabigatran following increased reports of adverse events.
Dabigatran was first approved in Australia in November 2009 for the prevention of venous thromboembolism in patients who had undergone major orthopedic surgery of the lower limb. In April 2011, approval was extended to thromboprophylaxis and stroke prevention in patients with atrial fibrillation.
The TGA says that they have observed an increase in adverse event reporting since the indication was extended.
According to TGA data, there have been 203 adverse events related to dabigatran use since 2009. Of these, 124 were serious adverse events, including 47 serious bleeding events overall, with 30 cases of serious gastrointestinal bleeding and six cases of serious intracranial bleeding. Around 60% of adverse events occurred in patients aged 75 years and older.
Analysis of these reports showed that "some" of the bleeding adverse events occurred during the transition from warfarin to dabigatran, and "many" occurred among patients on the reduced dosage regimen (110 mg).
As a result of the analysis, the TGA urges clinicians to give careful consideration to the suitability of their patients for dabigatran, "particularly with regard to the risks of bleeding and their current stability on warfarin or other anticoagulants." It adds that "special consideration should be given to the perioperative management of patients taking [dabigatran]."
Although standard laboratory tests are not validated for use with dabigatran, thrombin time and activated partial thromboplastin time (aPTT), could be used in emergency cases. An aPTT over 80 seconds is associated with a higher bleeding risk, states the advisory.
It adds that Australian experts are currently developing guidelines for the management of bleeding in patients taking dabigatran, but in the meantime clinicians should refer to the New Zealand guidelines on the subject.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Laura Dean