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Blood Thinners: 101


Blood thinners are used to prevent clots from forming in the blood. They are commonly prescribed for patients who have had knee or hip replacement surgery, have a history of stroke, have mechanical heart valves, or have a heart condition called atrial fibrillation.  Though blood thinners are important, lifesaving medications - they can be dangerous.


How do blood thinners work?

The drugs work by blocking the effects of Vitamin K-dependent clotting factors in the blood. A patient's dose is regulated based on his/her blood test results, which are reported as an International Normalized Ratio (INR) and should ideally fall in the range between 2 and 3; anything under 2 can mean that the blood is “too thick” and clots could form, whereas anything over 3 can mean that the blood is “too thin,” which could cause serious bleeding.  Maintaining the INR within therapeutic range is essential to sustaining the medication’s effectiveness and safety.


Why are blood thinners sometimes difficult to take safely?

The downside to blood thinners is that they are difficult to manage and have a narrow margin for safe use. Taking too much medicine can cause major bleeding, but not taking enough means blood clots can still form. Blood thinners are second only to chemotherapy drugs in having the highest risk of serious treatment-related complications. Some common potential side effects are nosebleeds, bleeding in the gums, unusual bleeding while shaving, and easy bruising. It is important to report bruises and bleeding to a doctor right away. 


Although this information may seem scary and make you think twice about the value of taking blood thinners, rest assured that the benefits outweigh the risks. To avoid potentially dangerous events, people taking blood thinners need to have their blood tested regularly, learn how to minimize interactions with medicines, vitamins and foods, and tell all of their healthcare providers that they are taking these medications. For more help, test your knowledge about your blood thinners.


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