Generic Medication guide:
What is Coumadin?
Coumadin is a brand name owned by a New York-based pharmaceutical company Bristol Myers Squib. The active substance of the medication responsible for its effect is Warfarin. It is also available under other names and at lower prices.
Warfarin is an indirect anticoagulant, i.e. it indirectly makes the blood thinner in the disorders in which it becomes thicker and can cause death. Its effect is due to the blocking of the synthesis of vitamin-K-dependent coagulation factors in the liver. The medication reduces their concentration in plasma and slows down the process of blood clotting.
The onset of the blood-thinning effect is observed 36–72 hours after the start of the administration of the formulation with the development of the maximum effect on the 5–7th day after the start of use. After discontinuation of the formulation use, the recovery of the activity of vitamin K-dependent coagulation factors occurs within 4–5 days.
When is Coumadin used?
You can buy Coumadin for the treatment and prophylaxis of thrombosis and obstruction of the blood vessels in:
- Acute and recurrent venous thrombosis, lung vessels obstruction;
- Transient ischemic attacks and strokes;
- Secondary prevention of myocardial infarction and prevention of thromboembolic complications after myocardial infarction;
- Prevention of thromboembolic complications in individuals with atrial fibrillation, damage to the heart valves or prosthetic heart valves;
- Prevention of postoperative thrombosis.
Prohibitions for Coumadin (Warfarin) use
- Established or suspected hypersensitivity to the drug;
- Acute bleeding;
- Pregnancy (I trimester and the last 4 weeks of pregnancy);
- Severe liver or kidney disease;
- Acute disseminated intravascular coagulation syndrome;
- Deficiency of proteins C and S;
- High risk of bleeding, including patients with hemorrhagic disorders;
- Varicose veins of the esophagus;
- Artery aneurysm;
- Lumbar puncture;
- Peptic ulcer and duodenal ulcer;
- Severe wounds (including surgery);
- Bacterial endocarditis;
- Malignant hypertension;
- Hemorrhagic stroke, intracranial hemorrhage.
Can Warfarin be used when expecting a baby?
It is strictly contraindicated during first three months of pregnancy and the last month of pregnancy. It can be used during the other months but only if the expected good substantially exceeds the risks. Warfarin quickly penetrates the placenta, it has a teratogenic effect on the fetus leading to the development of warfarin syndrome in the fetus at the 6th – 12th week of pregnancy. Manifestations of this syndrome: nasal hypoplasia (saddle nose deformation and other cartilage changes), short hands and fingers, optic nerve atrophy, cataracts leading to complete or partial blindness, mental and physical retardation and microcephaly.
The drug may cause bleeding at the end of pregnancy and during labor. Taking the drug during pregnancy can cause congenital malformations and lead to death of the fetus.
Coumadin (Warfarin) adverse effects
The most often adverse reaction is bleeding. Rarely diarrhea, enhanced activity of liver transaminases, eczema, skin necrosis; vasculitis, and hair loss can occur.
Bleeding is the most probable adverse effect of the formulation. The risk of intense bleeding is low but certain (on average per year from 0.9 to 2.7%). The benefits of treatment should outweigh this risk when considering the use of the formulation.
The risk of bleeding is higher with the combination of the Coumadin with antiplatelet medications such as Clopidogrel, aspirin, or other NSAIDs. The risk can also be elevated in elderly patients and in patients on hemodialysis.
Warfarin dosing information
The medication is taken once a day, preferably at the same time.
The duration of treatment is set by the doctor in accordance with the indications for use.
Control during treatment
Before starting the therapy, it is important to determine prothrombin time (PT). In the future, laboratory monitoring is carried out regularly every 4–8 weeks.
The duration of treatment depends on the clinical condition of the patient. Treatment can be canceled immediately.
- Patients who have not previously taken Warfarin are usually prescribed the initial dose of 5 mg/day (2 tablets per day) for the first 4 days. On the 5th day of treatment, the PT is determined and supporting dose of the formulation is prescribed in accordance with this indicator. Usually, the maintenance dose of the drug is 2.5–7.5 mg/day (1-3 tablets per day).
- Patients who have previously taken Warfarin are usually recommended to use the starting dose that is a double dose of the known supporting dose of the formulation and is prescribed for the first 2 days. Treatment is then continued using a known maintenance dose. On the 5th day of treatment, PT is monitored and the dose is adjusted in accordance with this indicator. It is advised to maintain a prothrombin time from 2 to 3 in the case of prevention and treatment of venous thrombosis, lung vessels obstruction, atrial fibrillation, dilated cardiomyopathy, complicated valvular heart disease, prosthetic heart valves with bioprostheses. Higher rates of PT from 2.5 to 3.5 are advised for prosthetic heart valves with mechanical prostheses and complicated acute myocardial infarction.
- Children: data on the use of Warfarin in children is limited. The initial dose is usually 0.2 mg / kg / day for normal liver function and 0.1 mg / kg / day for abnormal liver function. Maintenance dose is selected in accordance with the indicators of PT. Recommended levels of PT are the same as in adults. The decision on the appointment of warfarin and monitoring the treatment of children should be carried out by an experienced specialist.
- Elderly patients: there are no special recommendations for the use of Warfarin in this group of patients. However, elderly patients should be carefully monitored, as they have a higher risk of negative reactions.
- Patients with liver failure: an abnormal liver function increases sensitivity to Warfarin, since the liver produces clotting factors and also metabolizes warfarin. This group of patients requires careful monitoring of PT indicators.
- Patients with kidney failure: in patients with impaired renal function, it is required to lower the dose of Warfarin and conduct careful monitoring.
The dosages of the drug need also to be altered before or after a surgery. Make sure to consult a specialist before you buy Warfarin.
The indicator of efficiency is at the borderline of bleeding, so the patient may develop minor bleeding (including, for example, gingival bleeding).
Treatment of an overdose: in mild cases, reducing the dose of the drug or stopping treatment for a short period; with minor bleeding - discontinuation of the drug to achieve the PT target level. In the case of the development of severe bleeding, hospitalization and the introduction of vitamin K, the appointment of activated charcoal, coagulation factor concentrate, and other treatment methods are used.
If oral anticoagulants are indicated for further administration, large doses of vitamin K should be avoided, since resistance to warfarin develops within 2 weeks.
It is not recommended to start or stop taking other drugs, as well as to change the dose of drugs taken without consulting with your doctor.
With simultaneous appointment, it is also necessary to consider the effects of the termination of induction and / or inhibition of the effect of warfarin by other drugs.
- The risk of severe bleeding increases while taking warfarin with drugs that affect platelet levels and primary hemostasis: acetylsalicylic acid, clopidogrel, ticlopidine, dipyridamole, most NSAIDs (with the exception of COX-2 inhibitors), antibiotics of the penicillin group in large doses.
- You should also avoid the combined use of warfarin with drugs that have a pronounced inhibitory effect on the cytochrome P450 system, such as cimetidine and chloramphenicol, which, if taken,elevates the risk of bleeding for several days. In such cases, cimetidine can be replaced, for example, ranitidine or famotidine.
Precautions and special recommendations
- A prerequisite for warfarin therapy is strict patient compliance with the prescribed dose of the formulation.
- Patients suffering from alcoholism, as well as individuals with dementia may be unable to comply with the prescribed regimen of warfarin.
- Conditions such as fever, hyperthyroidism, decompensated heart failure, alcoholism with concomitant liver damage, may enhance the effect of warfarin. In hypothyroidism, the effect of warfarin can be reduced. In the case of renal failure or nephrotic syndrome, the level of free fraction of warfarin in the blood plasma increases, which, depending on the associated diseases, can lead to both an increase and a decrease in the effect. In the case of moderate liver failure, the effect of warfarin is enhanced.
In all of the above states, careful monitoring of the level of PT should be carried out.
- Patients receiving warfarin are recommended paracetamol, tramadol or opiates as painkillers.
- Patients with a mutation of the gene encoding the CYP2C9 enzyme have a longer elimination of warfarin. These patients require lower doses of the drug, because when taking the usual therapeutic dose elevates the risk of bleeding.
- Warfarin should not be taken in patients with rare hereditary intolerance to galactose, lactase deficiency, glucose-galactose malabsorption syndrome due to the presence of lactose in the preparation (as an adjuvant).
- If necessary, the onset of a rapid antithrombotic effect is recommended to begin treatment with the introduction of heparin; then, within 5–7 days, combination therapy with heparin and warfarin should be carried out until the target level of PT is maintained for 2 days.
- In individuals with protein C deficiency there is a risk of skin necrosis at the start of warfarin therapy. Such therapy should begin without a shock dose of warfarin even with heparin. Individuals with protein S deficiency may also be at risk, and in these circumstances, a slower initiation of the therapy is advised.
- In the case of individual resistance to warfarin (it is very rare), from 5 to 20 shock doses of warfarin are necessary to achieve a therapeutic effect. If the use of the formulation in such individuals is ineffective, other possible causes should be identified - simultaneous use of warfarin with other drugs (see “Interaction”), inadequate diet, laboratory errors.
- Treatment of elderly patients should be carried out with special precautions, because the synthesis of coagulation factors and hepatic metabolism in these individuals is reduced, as a result of which an excessive effect from the action of warfarin may occur.
- It is advised to use caution in individuals with impaired renal function, as a result of which the level of PT should be monitored more frequently in patients at risk of hypercoagulation, for example, in severe hypertension or kidney disease.
Our doctor prescribes online for free, and there is no doctor’s consultation fee.
All orders arrive in discrete unmarked parcels. We leave the shipment description blank.
For more answers see the FAQ section