Recent advances in anticoagulation therapies were explained in the latest installment of the Grand Rounds lectures series at Weill Cornell Medicine-Qatar (WCM-Q). Dr Liam Fernyhough, Assistant Professor of Medicine at WCM-Q, gave a brief history of the evolution of anticoagulation medications, which are used to prevent blood clots in at-risk patients, thereby reducing the likelihood of life-threatening conditions such as strokes and heart attacks.
According to Dr Fernyhough the first anticoagulants were developed in the US in the 1930s after the outbreaks of fatal haemorrhagic disease among cattle were found to be caused by animals being fed moldy hay. Researchers analysed the mold and isolated a compound called dicoumarol, which they found to be a powerful anticoagulant. This was developed into a rat poison called Warfarin that was later found to be safe and an effective therapeutic anticoagulant for human use.
Warfarin, however, has a number of drawbacks, as the dosage differs significantly between patients requiring laboratory monitoring of the patient, it has many interactions with other drugs, and it is affected by diet as foods high in Vitamin K diminish its effects.
Dr Fernyhough, who is also Senior Consultant in Hematology at the National Center for Cancer Care and Research at Hamad Medical Corporation, said these issues are all problematic, but the number one problem with Warfarin is bleeding.
If we could develop a drug that had the anticoagulant properties of Warfarin but did not cause bleeding, had fewer interactions with other drugs, was not affected by diet, and could be given as a fixed dose, that would be highly beneficial for patients.’
He then explained that four effective Warfarin alternatives – Dabigatran, Rivaroxaban, Apixaban, Edoxaban – all require differential dosage depending on a number of variables. These drugs also have problem interacting with other drugs. While Apixaban and Edoxaban cause slightly less bleeding than Warfarin, Dabigatran and Rivaroxaban cause about the same amount.
They are not the wonder-drugs that we hoped for, but they certainly have a number of good features. Many clinicians prefer to continue using Warfarin, because it still has many benefits in selected stable patients. However, when you do a meta-analysis of these newer therapies, specifically relating to atrial fibrillation (abnormal heart rhythm), all-cause mortality is decreased as compared to Warfarin. This is really powerful information. It is thought that this reduction in all-cause mortality is because of a significant reduction in haemorrhagic stroke and intracranial bleeding that occurs when we are using the newer therapies, although there is a slightly increased risk of gastrointestinal bleeding.’
The lecture titled ‘A New Era of Anticoagulation’, was accredited by the Qatar Council for Healthcare Practitioners-Accreditation Department (QCHP-AD) and by the Accreditation Council for Continuing Medical Education (ACCME).
For updates and more information about the WCM-Q Grand Rounds Lecture series, visit qatar-weill.cornell.edu.