Blood thinners, or better anticoagulants, directly or indirectly interfere with the complex process of blood clotting. They are intended to reduce the risk of clotting in the “wrong place” within the vascular system in the brain, heart, or lungs, thereby preventing stroke, embolism, or heart attack.
What are blood thinners?
To reduce the risk of blood clot formation in the presence of known risk factors, anticoagulants (blood thinners) are given as prophylaxis to directly or indirectly make the process of blood clotting more difficult. The complex process of blood clotting (coagulation) to stop bleeding after an internal or external injury is, in principle, life-saving, since otherwise any minor injury would lead to hemorrhage. In the case of artificially inflicted injuries due to surgery or heart conditions – such as atrial fibrillation – there is a risk that the process of coagulation will be unintentionally triggered by mechanical stimuli and that a blood clot, a thrombus, will form inside the vessels. The thrombus can be carried along by the bloodstream and cause a vessel occlusion at an unfavorable location, which can lead directly to a heart attack, stroke or pulmonary embolism. To reduce the risk of blood clot formation in the presence of known risk factors, anticoagulants (blood thinners) are administered as prophylaxis, which directly or indirectly impede the process of blood clotting. Apart from side effects, there is the problem of optimal dosage. Too high a dose can lead to dangerous spontaneous internal bleeding or persistent bleeding after injury.
Medical application, effect, and use
Widespread atrial fibrillation, use of artificial heart valves and stents, and impending surgery all argue for prophylaxis. Direct therapeutic use may be for treatment of thrombosis and arteriosclerosis. There are now a large number of drugs and substance groups that intervene directly or indirectly at specific points in the coagulation mechanism and have specific advantages and disadvantages. The first stage of blood clotting begins with the platelets (thrombocytes) sticking together, which is feared after the insertion of stents, after a heart attack or when arteriosclerosis is diagnosed. For prevention, therefore, drugs are used that inhibit platelet aggregation, such as the well-known acetylsalicylic acid (ASA), the main active ingredient in aspirin. Other active ingredients, often administered in combination with ASA, include clopidogrel, prasugrel, and ticagrelor. Low-molecular-weight heparins are preferred for thrombosis prophylaxis after surgery and for the treatment of pulmonary embolism and venous thrombosis. They are injected subcutaneously and directly inhibit coagulation factor X (Xa) together with the body’s own anticoagulant AT III. For patients who need to maintain anticoagulation protection over a longer period of time – or even for life – coumarins with the main active ingredient phenprocoumon (Marcumar) or warfarin were the drugs of choice for decades. These are vitamin K antagonists that indirectly inhibit certain clotting factors by inhibiting vitamin K activity. In recent years, new drugs have been approved that target clotting factor X (Xa) directly and eliminate the need for regular testing of the blood clotting factor INR.
Herbal, natural, homeopathic, and pharmaceutical blood thinners.
The active ingredient phenprocoumon, a vitamin K antagonist and effective ingredient in the drug Marcumar, is originally of plant origin (woodruff) but is now produced synthetically. Citrate, another natural “blood thinner” is mainly used for preventive anticoagulation during dialysis. Hirudin, originally obtained from medicinal leeches, has an anticoagulant effect via its blocking action on thrombin synthesis. Today, hirudin is obtained from genetically modified yeast cells under the names lepirudin and desirudin. For therapeutic purposes, the agents are administered parenterally via subcutaneous injections or intravenously. Acetylsalicylic acid is one of the active ingredients that counteracts the adhesion of platelet aggregation and is therefore also known as an antiplatelet agent. The active ingredient is also of plant origin. It was originally produced from salicyl, a group of substances extracted from willow bark. Acetylsalicylic acid is produced synthetically in larger quantities.The group of heparins, which are mainly used for a limited time to prevent thromboses and embolisms after operations, are of animal origin and are still obtained from the intestines of pigs. Since 2008, the new drugs Pradaxa, Xarelto and Efient.have been approved as anticoagulants to prevent thrombosis and embolism. They are easier to use because they eliminate the need to constantly monitor the clotting factor INR in the blood.
Risks and side effects
Basic risks associated with the use of blood thinners include (unintentional) overdose, which, in the case of vitamin K antagonists, can result from dietary changes or interactions with other medications. The newly approved drugs Pradaxa, Xarelto and Efient can be overdosed if, for example, two tablets are accidentally taken instead of one or if impaired kidney or liver function breaks down the active ingredients too slowly. In the event of an overdose, there is a risk of internal bleeding and also a risk that bleeding after injury may be difficult to stop. When taking vitamin K antagonists for a long time, it must be borne in mind that vitamin K has other important functions in the body’s calcium balance, i.e. in the formation of bones, in addition to its role in blood clotting, and provides a certain degree of protection against arteriosclerosis. If the vitamin is suppressed, these functions are also impeded, so that in the long term osteoporosis and arteriosclerosis are favored.
