Dosing of Marcumar®
Synonyms in a broader sense
Phenprocoumon (active ingredient name), coumarins, vitamin K antagonists (inhibitors), anticoagulants, anticoagulants
How is Marcumar® dosed?
That under the trade name Marcumar® known medicine contains the active ingredient Phenprocoumon, which belongs to the main group of Coumarins (Vitamin K antagonists) is counted.
The coumarins are molecules that suppress the natural processes of the Blood clotting affect and thus inhibit the coagulation of the blood (Anticoagulants).
The doctor treating you must determine the exact dosage for each patient. For this purpose, the so-called thromboplastin time must be determined before the actual start of treatment. During the entire intake phase, this is checked at regular, close intervals and the drug dosage is adjusted if necessary. Also the Quick and the INR value provide information about the body's ability to clot independently.
The INR value is an international measure for assessing blood coagulation. High values mean that the coagulation time is longer than the normal value and the tendency to bleed is correspondingly high. A low value, on the other hand, suggests a shortened blood clotting time and an associated increased risk of thrombosis.
Basically it can be said that anti-coagulant drugs such as Marcumar® increase the INR value and thus reduce the risk of thrombus formation.
At the beginning of the drug administration, it is likely that the patient's coagulation values fluctuate very strongly, which makes regular monitoring and adjustment of the dosage all the more necessary. According to some experts, the reason for this is the fact that therapy with the help of Marcumar® is usually initiated with a comparatively high dose of the drug.
Read more about the topic here: INR
The patient is encouraged to do this for the first two days 8 tablets within 24 hours to take.
However, this information varies from patient to patient, for this reason both the initial dose and each additional dose must be determined by the attending physician and must be adhered to by the patient.
Due to this comparatively high intake dose, the INR value can increase enormously in the first few days (values over 3.0) and thus the ability to clot blood can decrease accordingly. There is an apparently increased risk of bleeding, the chance of developing a thrombosis is apparently reduced. However, an increased INR value at the beginning of treatment is not a serious measure of actual blood clotting.
This fact is based on the fact that one of the Marcumar® influenced Clotting factors (Factor VII) a low plasma half-life of only
Has 5–6 hours. For this reason, after taking Marcumar for the first time, only the concentration of this one vitamin K-dependent coagulation factor decreases; in most cases, factors II, IX and X are still fully active. For some of these factors, the plasma half-life is up to 60 hours. Since these coagulation factors are also much more important for blood clotting, this is referred to as an apparent increase in the INR value.
The doctor will check the coagulation values after a few days and reduce the dose of medicine again.
The further daily dose to be taken depends on the values determined.
If the INR value is below the target value for the patient (the target is usually a INR from 2- 3.5) a daily dose of one and a half tablets (about 4.5 mg of the active ingredient) is recommended.
However, if the INR value determined in the check-up is within the target range, only one tablet (approximately 3 mg phenprocoumon) should be taken over 24 hours.
If the blood coagulation value is too high (from 3.5) the maximum daily dose must be reduced. In this case, the attending doctor usually prescribes half a tablet of Marcumar (i.e. 1.5 mg).
If an INR value of more than 4.5 is reached, the use of the drug must be suspended for the time being.
This list is intended to make it clear how dependent the maximum daily dose must be on the blood coagulation value measured in each case.
As a rule, after a “trial period”, only a so-called Maintenance dose administered from approximately one-half to one and a half Marcumar tablets per day. After the treated patients have been set accordingly, the INR value moves in a relatively constant measuring range.
Nevertheless, even after the desired value has been reached, the blood coagulation must be checked regularly, usually every three to four weeks, and the drug dosage adjusted if necessary.
The patient being treated should ensure that the Marcumar tablets are always taken at around the same time (preferably in the evening).
The drug must wholeshould be swallowed with sufficient liquid.
After stopping the Marcumar, it can again take 10-14 days for the anti-coagulant effect to expire and for normal coagulation to take place again. This fact can be explained by the fact that a sufficiently high concentration of fully activatable coagulation factors can only be formed after this time.
In Emergency situations it is therefore necessary to provide the missing coagulation factors II, VII, IX and X to the organism of external to reduce a possible risk of bleeding.
Even in connection with planned surgical interventions and dental treatments, it must always be remembered to stop taking the anti-coagulant drug early enough to prevent an increased tendency to bleed.
Marcumar® table
The active ingredient of Marcumar® is phenprocoumon and belongs to the group of vitamin K antagonists. Marcumar® should be dosed at the beginning of therapy. A standard schedule is available here for the first three days of therapy. This can be deviated from depending on body weight and general condition. Marcumar® is taken orally (via the food route) in tablet form.
The dosage scheme provides:
1st day of treatment: take 3 tablets at once
2nd day of treatment: take 2 tablets at once
From the 3rd day of treatment: regular blood tests (INR value) to check the effect
In the dosing phase, heparin should also be used. The heparin should be discontinued after three days. If the INR is in the target range (2-3), a maintenance dose between 0.25-1.25 tablets should be taken from the 4th day, depending on the INR value (8 International Normalized Ratio).
Dosage of Marcumar® according to the Quick value
The Quick value is a laboratory parameter for measuring blood clotting. Since the laboratory parameter varies from laboratory to laboratory, the Quick value is increasingly being replaced by the INR (International Normalized Ratio). This is more comparable among the laboratories because it does not show such a high degree of variability. The INR is therefore more informative than the Quick value.
Can you calculate the dosage of Marcumar®?
The dosage of Marcumar® is not calculated, but is based on the INR blood value. This is a value that is used to control blood clotting.
The Marcumar® therapy should achieve a value between 2 to 3 INR. If the value is below 2, the blood is too thick and the dosage of Marcumar® should be increased. Regular blood tests ensure the correct individual dosage. If the dose is too high or too low, a dose adjustment can be made immediately. It is important that in the event of symptoms of insufficient blood clotting (many bruises without an injury mechanism) or insatiable bleeding, a doctor must be consulted to check the INR value.
Marcumar® prevents the synthesis of some coagulation factors. These factors are made dependent on vitamin K. Because vitamin K is no longer available, these factors are no longer synthesized. The disadvantage of Marcumar® is that its effect can only be reversed by the administration of vitamin K or by synthetically produced coagulation factors (prothrombin concentrate). However, it takes a few days for the vitamin K to work. Therefore, the Marcumar® must be discontinued about seven days before planned operations. Alternatively, heparin can be injected during this time. Regular blood tests should always be considered.
Marcumar® for atrial fibrillation
Marcumar® is the first choice for atrial fibrillation. Atrial fibrillation is a circulating excitation in the two atria of the heart. As a result, some parts of the atria stand still and no longer take part in the contraction. The so-called auricular ears are located in the atria. They are cavities in the atria where blood can collect due to decreased evacuation of the atria. Here the blood comes to a standstill and then coagulates. The result is thrombus formation. If the thrombi leave the left atrium, they enter the aorta (main artery) via the left ventricle and continue into the brain (sleep attack), into the arms or legs (peripheral arterial occlusion) or into the intestinal arteries (mesenteric infarction). If the thrombi leave the right atrium, they reach the lungs via the right heart via the pulmonary artery and trigger a pulmonary embolism. Therefore, it is very important to have anticoagulation for atrial fibrillation. Here, too, the INR should be between 2-3.
Read more on the subject at: Therapy of atrial fibrillation
Marcumar® after an operation
The effect of Marcumar® is very difficult to control and can only be reversed with external coagulation factors or with vitamin K. Therefore, the Marcumar® must be discontinued before an operation. After the operation, heparin should be injected instead of Marcumar® for about seven days in order to prevent any unstoppable bleeding. Therapy with Marcumar® can be continued after the seven days. During the first 72 hours, heparin should be injected parallel to the restarted therapy with Marcumar®, as Marcumar® does not take effect until 72 hours after the first dose. After the 72 hours, the heparin can be discontinued, but an INR control should be carried out.
Taking Marcumar® after heparin
Heparin is also an anticoagulation (anticoagulant) drug. The heparin has a much shorter effective time than the Marcumar®. Therefore it is more controllable. There is also a drug (antidote) for heparin that cancels the effects of heparin. The drug is the protamine. In the case of therapy with heparin, dosing with Marcumar® can be started in parallel. After three days, the heparin should be discontinued and the INR checked. The Marcumar® can be replaced by the heparin at any time. If the patient is well tolerated, however, Marcumar® should be started again in the long term and the therapy of choice.
