Regular monitoring of anticoagulant use
Coagulation or blood clotting is a protective mechanism of the body against bleeding. Normally, clotting only occurs when there is blood loss from a damaged blood vessel. However, there are several conditions that can cause blood clots to form in the absence of active bleeding. When this occurs, a person may be at an increased risk of thromboembolic disease.
In thromboembolic disease, fragments of blood clots dislodge and circulate in the blood, potentially obstructing blood vessels in the:
- lungs and causing a pulmonary embolism, or
- vessels in the heart and causing a heart attack, or
- brain and causing a stroke.
These conditions are all potentially fatal.
Therefore, when a person is at high risk of one of the above conditions, anticoagulants (medicines which thin the blood and reduce the formation of clots), are prescribed to minimize the risk of blood clots forming. People who require anticoagulant therapy will be prescribed an anticoagulant. There are many anticoagulants, including:
heparin (Hepalean) | warfarin (Coumadin) | rivaroxaban (Xarelto) | dabigaran (Pradaxa) | apixaban (Eliquis) | edoxaban (Savaysa) | enoxaparin (Lovenox) | fondaparinux (Arixtra) | dalteparin (Fragmin)
Knoxville Hospital & Clinics’ Anticoagulation Program offers extensive monitoring of patients using anticoagulants. A patient’s primary care provider refers them to the Anticoagulation Program.
Clinic staff perform international normalized ratio (INR) testing, conduct patient assessments, and adjust anticoagulant doses as needed for each patient’s INR goal parameters.
The INR is a laboratory measurement of how long it takes blood to form a clot. We use it to determine the effects of the anticoagulants on the clotting system. When the INR is too high it means that the blood is too thin. When it is too low, the blood is too thick.
Regular monitoring is important with anticoagulants because:
- There is very small difference between the lowest dose that gives a good effect and the highest dose before side effects (which may be serious) are experienced.
- The doses used by different individuals to achieve the same effect can be highly variable.
- Several drugs interact with the medication to either increase or decrease its effectiveness.
- What a person eats can affect the action of the drug.