Anticoagulant drugs can work by interfering with thrombin, blocking production of clotting factors, or interrupting blood platelets. A doctor prescribes a drug on the basis of the patient's underlying health and the need for anticoagulants, whether they are for preventing clots after surgery or treating a patient with a chronic clotting disorder. Some classes of anticoagulants can be very dangerous if they are not used properly, and it is important to be attentive while receiving drug information.
Heparin is an example of a drug that works by blocking the activity of thrombin to inhibit clot formation. Direct thrombin inhibitors like dabigatran and vivalirudin are other examples of anticoagulant drugs that work by interacting with thrombin. These drugs can work very quickly and may be useful for a patient in medical crisis or in a situation where a doctor wants the drug to work rapidly for other reasons.
The coumadins are anticoagulant drugs that work by interfering with the production of clotting factors in the liver. They include drugs like warfarin and can take several hours or days to become effective. Patients may receive these drugs for long term maintenance if a doctor thinks it is necessary. The patient will need periodic blood tests to check on the levels of clotting factors in the blood and determine if any complications are developing.
Patients can also take antiplatelet drugs like aspirin. These can also be taken in the long term to address a clotting problem, and patients may remain on maintenance therapy for cardiovascular health. Some of these anticoagulant drugs are available over the counter, but patients should make sure their doctors know they are taking them, in case they are at risk of a bad drug interaction.
The anticoagulant drugs most suitable for a patient depend on why the patient needs the drugs, the patient's medical history, and the length of time the patient will need to use the drugs. Doctors have to consider issues like a history of adverse drug interactions, the potential for complications with long term use, and the patient's ability to follow a drug protocol safely.
Other anticoagulant drugs are for use in research or diagnostic testing, not for living patients. These include oxalate and citrate, both used in the lab to prevent blood samples from clotting. They are not safe for human use and can potentially cause health problems if people ingest them. Usually stores of drugs not intended for human use are clearly labeled and kept separate from other supplies to minimize the risk of accidents.