Safety and efficacy of new generation anticoagulant drugs

Interview with Professor Rossella Marcucci, director of Sod atherothrombotic diseases of the University Hospital of Careggi

di Laura d'Ettole

What are new generation anticoagulants and what are they for? Pharmacology is making great strides and in the last ten years these new drugs have been created that are easier to use, more compatible with a varied lifestyle and diet of the patient. Prof. Rossella Marcucci talks about it.

Professor Marcucci, new generation anticoagulant drugs have been on the market for just over ten years, can you explain the differences compared to the past?

Prof. to Rossella Marcucci

Prof. to Rossella Marcucci

The first generation anticoagulants, called vitamin K antagonists (Coumadin and Sintrom), in use since the 50s, are a group of drugs that require periodic control of the INR in the laboratory for dose adjustment. Usually a cps is needed once a week in the first weeks, to obtain a value on the basis of which the definitive dosage is established (INR value between 2 and 3). Checks are then required, on average every 15 days. These drugs are generally less "manageable" than the more recent ones because they are indirectly acting drugs. Let me explain, the anticoagulant action of the drug is affected by many factors, mainly dietary, and to ensure that the INR value remains constant, it is necessary to reduce possible interferences: as regards the diet, there are no prohibited foods, but it is appropriate follow a constant 'monotonous' diet to avoid excessive variations in the anticoagulant effect of the drug. The situation is different for the latest generation drugs.

What are the characteristics of the latter?

The new drugs are direct anticoagulants, ie they block blood clotting without interference, they are not influenced by other variables. They have a high bioavailability, as they say, that is, all the drug I introduce will have an anticoagulant effect. Dosage can be decided initially based on age, kidney function, gender and weight. The associated diet is free for the patient. Another important effect is that they showed a higher safety profile with regard to side effects. In both old and new drugs, it is clear, the most important side effect is bleeding, but in the new ones the risk of severe bleeding, such as cerebral haemorrhage, has been greatly reduced.

In what cases are anticoagulants prescribed in patients with cardiomyopathy?

In cardiomyopathies when - and it often happens - the most frequent arrhythmia appears, atrial fibrillation, and in case of dilated cardiomyopathy to avoid the formation of thrombus in the atrium or left ventricle.

A crucial question: in which cases is it advisable to prescribe the old or new generation of drugs?

The drugs in force for years, it is clear, remain very valid and are still used in certain clinical conditions. The new ones can be used in the case of atrial fibrillation, with the exclusion of patients with mechanical valve prostheses and those with severe mitral stenosis. Patients with atrial fibrillation, with the aging of the population, are much more numerous than is commonly believed, also because atrial fibrillation can be "hidden", that is, not perceived by the subject. Therefore the audience of potential patients is quite large. Another field of use is represented by patients with deep vein thrombosis and / or pulmonary embolism.

What are the contraindications for the new anticoagulant drugs?

Paradoxically, their ease of use can cause the patient to be unaware of what they are taking and forget to take them or avoid medical checks. In a word, the risk is above all behavioral, because the patient, due to unconscious lightness, can remain uncovered for the various pathologies he is treating. Controls, on the other hand, remain very important, at least once every six months. However, these are anticoagulant drugs at risk of bleeding: blood counts and renal function (i.e. measurement of creatinine) must be checked at least every six months.

Until a few months ago, prescribing these new drugs was not easy, now something has changed ...

There is now a drug prescribing pathway with a "note 97", a technical term, which allows prescribing by the treating physician in the event of atrial fibrillation. That is, it is not a normal prescription but a prescription within a therapeutic plan. Until recently all this was the responsibility of "prescribers", that is, specialists related to the health service, while now the family doctor can do it too. A note about costs that basically affects all new drugs. It should be noted that these new products are much more expensive, almost twenty times as much, than the old drugs. And this not so much because of the use of particular technologies or components, but only because it took a long process and a large use of resources to develop them. That's the problem with all new drugs !!