Warfarin Orion tablets are used for the following indications:
treatment and prevention of deep vein thrombosis and pulmonary embolism; secondary prevention of myocardial infarction and prevention of thromboembolic complications (cerebral embolism or systemic embolism) after myocardial infarction; prevention of thromboembolic complications (cerebral embolism or systemic embolism) in patients with atrial fibrillation, heart valve disease or prosthetic heart valves.
Composition
One tablet contains (active ingredient) warfarin sodium 3 mg.
Excipients: lactose monohydrate, corn starch, gelatin, magnesium stearate, indigo carmine E 132.
Contraindication
Bleeding tendency (Von Willebrand's disease, hemophilia, thrombocytopenia and platelet dysfunction), acute bleeding to avoid the risk of severe bleeding within 72 hours after major surgery, within 48 hours in the postpartum period, pregnancy, severe renal failure, severe hepatic failure and cirrhosis, untreated or uncontrolled arterial hypertension, recent intracranial hemorrhage, medical conditions predisposing to intracranial hemorrhage, such as cerebral aneurysm, aortic aneurysm, tendency to fall, lumbar puncture, central nervous system or eye surgery, gastrointestinal or renal bleeding and their complications, diverticulosis or malignant tumors, esophageal varices, infective endocarditis or exudative pericarditis, dementia, psychosis, alcoholism and other situations where compliance may be compromised. insufficient and anticoagulant therapy cannot be carried out safely enough, hypersensitivity to warfarin or to any of the excipients.
Method of application
Target INR (International Normalized Ratio) level for oral anticoagulant therapy:
prevention of thromboembolic complications in patients with prosthetic heart valves - INR 2.5-3.5; other indications - INR 2.0-3.0.
Adults
Patients of normal weight with a spontaneous INR below 1.2 should be given 10 mg of warfarin for three consecutive days. The dose should then be calculated according to the information below, based on the INR measurement on the fourth day.
In outpatient settings and in patients with hereditary protein C or S deficiency, the recommended initial dose is 5 mg of warfarin for three consecutive days. The dose should then be calculated according to the information below, based on the INR measurement on the fourth day.
For elderly patients, patients with low body weight, with a spontaneous INR above 1.2, or those who have concomitant diseases or are receiving any drugs that affect the effectiveness of anticoagulant therapy, the recommended initial dose is 5 mg of warfarin for the next two days. The dose should then be calculated according to the information below, based on the INR measurement on the third day.
Recommended dosage of the drug "Warfarin-FS":
day 1 - 10 (5.0) mg/day; day 2 - 10 (5.0) mg/day; day 3: INR <2.0 - 10 (5.0) mg/day; INR from 2.0 to 2.4 - 5.0 mg/day; INR from 2.5 to 2.9 - 3.0 mg/day; INR from 3.0 to 3.4 - 2.5 mg/day; INR from 3.5 to 4.0 - 1.5 mg/day; INR> 4.0 - skip one day of administration; day 4-6: INR <1.4 - 10.0 mg/day; INR from 1.4 to 1.9 - 7.5 mg/day; INR from 2.0 to 2.4 - 5.0 mg/day; INR from 2.5 to 2.9 - 4.5 mg/day; INR from 3.0 to 3.9 - 3.0 mg/day; INR from 4.0 to 4.5 - skip one day of administration, then - 1.5 mg/day; INR> 4.5 - skip two days of administration, then - 1.5 mg/day; day 7 (weekly dose of the drug "Warfarin-FS"): INR from 1.1 to 1.4 - increases by 20%; INR from 1.5 to 1.9 - increases by 10%; INR from 2.0 to 3.0 - the dose is maintained; INR from 3.1 to 4.5 - decreases by 10%; INR> 4.5 - skip the administration until the INR becomes <4.5, then - continue treatment with a dose reduced by 20%.
INR measurements should be performed daily until a stable target level is reached, which is usually established on the 5th or 6th day of treatment. INR measurements should then be performed weekly, reaching a 4-week interval. In the case of large deviations in INR levels or in patients with liver disease or diseases that affect the absorption of vitamin K, measurement intervals may be less than 4 weeks. The appointment of new or cancellation of previously taken drugs requires additional INR measurements. With long-term therapy, adjustments are made to the weekly dose of warfarin in accordance with the information above. If the dose requires adjustment, the next INR measurement should be performed one or two weeks after the adjustment. After this, measurements are continued until 4-week intervals are reached.
Planned operations
Pre-, post-, and post-anticoagulant therapy is performed as indicated below.
Determine the MNI one week before the scheduled surgery.
Stop warfarin 1-5 days before surgery. If the patient is at high risk of thrombosis, low molecular weight heparin should be administered subcutaneously for prophylaxis.
The duration of the pause in taking warfarin depends on the INR. Stop taking warfarin:
5 days before surgery if MNI> 4.0; 3 days before surgery if MNI = 3.0 to 4.0; 2 days before surgery if MNI = 2.0 to 3.0.
Determine the INR the evening before surgery and administer 0.5-1.0 mg of vitamin K1 orally or, if INR> 1.8.
Continue subcutaneous administration of low molecular weight heparin for 5-7 days after surgery with concomitant resumption of warfarin.
Continue warfarin at the usual maintenance dose on the same evening after minor surgery and on the day the patient begins receiving enteral nutrition after major surgery.
Children
Anticoagulant therapy in children is carried out under the supervision of a pediatrician. Doses are selected according to the data below.
Recommended dosage:
day 1 - if the baseline INR value is from 1.0 to 1.3, the initial dose is 0.2 mg/kg of body weight; days 2 to 4, if the INR value (maintenance dose): from 1.1 to 1.3 - repeat the initial dose; from 1.4 to 1.9 - 50% of the initial dose; from 2.0 to 3.0 - 50% of the initial dose; from 3.1 to 3.5 - 25% of the initial dose; > 3.5 - stop taking the drug until the INR reaches <3.5, then resume treatment with a dose 50% lower than the previous dose; maintenance therapy, if the INR value (weekly dose): from 1.1 to 1.4 - increase the dose by 20%; from 1.5 to 1.9 - increase the dose by 10%; from 2.0 to 3.0 - no change; from 3.1 to 3.5 - reduce the dose by 10%; > 3.5 - stop taking the drug until the INR is <3.5, then resume treatment with a dose 20% less than the previous one.
Application features
Pregnant women
Warfarin is contraindicated during pregnancy.
Warfarin does not pass into breast milk, so breastfeeding can be continued during warfarin therapy.
Drivers
The drug does not affect the ability to drive or operate complex mechanisms.
Overdose
In cases of gradual overdose, it is usually sufficient to stop taking the drug.
In acute overdose, gastric emptying is not recommended due to the risk of bleeding. Activated charcoal should be administered again to prevent absorption and enterohepatic circulation of warfarin. If activated charcoal is administered, vitamin K, which may be required later, should be administered parenterally (intravenously). In the event of bleeding, the effect of warfarin can be reversed by the administration of vitamin K, clotting factor concentrate, or fresh frozen plasma. If oral anticoagulants are indicated in the future, large doses of vitamin K exceeding 10 mg should be avoided, as patients become resistant to warfarin within two weeks.
Side effects
The most commonly reported adverse reaction (1% to 10%) is bleeding, which occurs in about 8% of patients taking warfarin annually. Moderate bleeding occurs annually in 6%, severe bleeding in 1%, and fatal bleeding in 0.25% of patients. A common risk factor for intracranial hemorrhage is untreated or uncontrolled hypertension. The likelihood of bleeding increases if the INR is significantly above the target level. If bleeding begins at an INR within the target level, this indicates the presence of other underlying conditions that should be investigated.
Storage conditions
Store at a temperature not exceeding 25 °C, out of the reach of children. Store in a tightly closed bottle. Keep the bottle in the outer carton.
Shelf life - 3 years.
