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Cardiac products (Warf)
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Warf
Warfarin Sodium Tablets
COMPOSITION
WARF-1
Each tablet contains:
Warfarin sodium (crystalline) USP equivalent to Warfarin sodium (anhydrous) 1 mg
WARF-2
Each tablet contains:
Warfarin sodium (crystalline) USP equivalent to Warfarin sodium (anhydrous) 2 mg
WARF-5
Each tablet contains:
Warfarin sodium (crystalline) USP equivalent to Warfarin sodium (anhydrous) 5 mg
INDICATIONS
• Prophylaxis and/or treatment of venous thrombosis and its extension pulmonary embolism
• Prophylaxis and/or treatment of thromboembolic complications associated with atrial fibrillation and/or cardiac valve replacement
• To reduce the risk of death, recurrent myocardial infarction, and thromboembolic events such as stroke or systemic embolization after myocardial infarction
DOSAGE AND ADMINISTRATION
The dosage and administration of warfarin must be individualized for each patient according to the particular patient`s PT/INR response to the drug.
Venous thromboembolism (including deep venous thrombosis [DVT] and pulmonary embolism [PE])
For patients with a first episode of DVT or PE secondary to a transient (reversible) risk factor, treatment with warfarin for 3 months is recommended. For patients with a first episode of idiopathic DVT or PE, warfarin is recommended for at least 6 to 12 months. For patients with two or more episodes of documented DVT or PE, indefinite treatment with warfarin is suggested. For patients with a first episode of DVT or PE who have documented antiphospholipid antibodies or who have two or more thrombophilic conditions, treatment for 12 months is recommended and indefinite therapy is suggested. For patients with a first episode of DVT or PE who have documented deficiency of antithrombin, deficiency of Protein C or Protein S, or the Factor V Leiden or prothrombin 20210 gene mutation, homocystinemia, or high Factor VIII levels (>90th percentile of normal), treatment for 6 to 12 months is recommended and indefinite therapy is suggested for idiopathic thrombosis. The risk-benefit should be reassessed periodically in patients who receive indefinite anticoagulant treatment. The dose of warfarin should be adjusted to maintain a target INR of 2.5 (INR range, 2.0 to 3.0) for all treatment durations.
Atrial fibrillation (AF)
An INR of 2.0 to 3.0 should be used for long-term warfarin therapy in appropriate patients. |
Oral anticoagulation therapy with warfarin is recommended in patients with persistent or paroxysmal AF (PAF) (intermittent AF) at high risk of stroke (i.e., having any of the following features: prior ischemic stroke, transient ischemic attack, or systemic embolism, age >75 years, moderately or severely impaired left ventricular systolic function and/or congestive heart failure, history of hypertension, or diabetes mellitus). In patients with persistent AF or PAF, age 65 to 75 years, in the absence of other risk factors, but who are at intermediate risk of stroke, antithrombotic therapy with either oral warfarin or aspirin, 325 mg/day, is recommended. For patients with AF and mitral stenosis, anticoagulation with oral warfarin is recommended. For patients with AF and prosthetic heart valves, anticoagulation with oral warfarin should be used; the target INR may be increased and aspirin added depending on valve type and position, and on patient factors.
Post-myocardial infarction
In healthcare settings in which meticulous INR monitoring is standard and routinely accessible, for both high- and low-risk patients after myocardial infarction (MI), long-term (up to 4 years) high-intensity oral warfarin (target INR, 3.5; range, 3.0 to 4.0) without concomitant aspirin or moderate-intensity oral warfarin (target INR, 2.5; range, 2.0 to 3.0) with aspirin is recommended. For high-risk patients with MI, including those with a large anterior MI, those with significant heart failure, those with intracardiac thrombus visible on echocardiography, and those with a history of a thromboembolic event, therapy with combined moderate-intensity (INR, 2.0 to 3.0) oral warfarin plus low-dose aspirin ( < 100 mg/day) for 3 months after the MI is suggested.
Mechanical and Bioprosthetic heart valves
For all patients with mechanical prosthetic heart valves, warfarin is recommended. For patients with a St. Jude Medical bileaflet valve in the aortic position, a target INR of 2.5 (range, 2.0 to 3.0) is recommended. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, the 7th ACCP recommends a target INR of 3.0 (range, 2.5 to 3.5). For patients with caged ball or caged disk valves, a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/day is recommended. For patients with bioprosthetic valves, warfarin therapy with a target INR of 2.5 (range, 2.0 to 3.0) is recommended for valves in the mitral position and is suggested for valves in the aortic position for the first 3 months after valve insertion.
Recurrent Systemic Embolism and Other Indications
Oral anticoagulation therapy has not been evaluated by properly designed clinical trials in patients with valvular disease associated with atrial fibrillation, patients with mitral stenosis, and patients with recurrent systemic embolism of unknown etiology. A moderate dose regimen (INR 2.0 to 3.0) is recommended for these patients.
An INR of greater than 4.0 appears to provide no additional therapeutic benefit in most patients and is associated with a higher risk of bleeding
Initial dosage
The dosing of warfarin must be individualized according to the patient`s sensitivity to the drug as indicated by the PT/INR. It is recommended that warfarin therapy be initiated with a dose of 2 to 5 mg per day with dosage adjustments based on the results of PT/INR determinations. Low initiation doses are recommended for elderly and/or debilitated patients and patients with potential to exhibit greater than expected PT/INR response to warfarin. Based on limited data, Asian patients may also require lower initiation and maintenance doses of warfarin.
Maintenance
Most patients are satisfactorily maintained at a dose of 2 to 10 mg daily. The individual dose and interval should be gauged by the patient`s prothrombin response.
Duration of therapy
The duration of therapy in each patient should be individualized. In general, anticoagulant therapy should be continued until the danger of thrombosis and embolism has passed.
Missed Dose
The anticoagulant effect of warfarin persists beyond 24 hours. If the patient forgets to take the prescribed dose of WARF at the scheduled time, the dose should be taken as soon as possible on the same day. The patient should not take the missed dose by doubling the daily dose to make up for missed doses, but should refer back to his or her physician.
Conversion from heparin therapy
Since the anticoagulant effect of warfarin is delayed, heparin is preferred initially for rapid anticoagulation. Conversion to warfarin may begin concomitantly with heparin therapy or may be delayed by 3 to 6 days. To ensure continuous anticoagulation, it is advisable to continue full-dose heparin therapy and that warfarin therapy be overlapped with heparin for 4 to 5 days, until warfarin has produced the desired therapeutic response as determined by PT/INR. Once this has been achieved, heparin may be discontinued.
CONTRAINDICATIONS
Anticoagulation is contraindicated in any localized or general physical condition or personal circumstance in which the hazard of hemorrhage might be greater than the potential clinical benefits of anticoagulation such as:
• Pregnancy
• Hemorrhagic tendencies or blood dyscrasias
• Recent or contemplated surgery of:
(1) central nervous system;
(2) eye;
(3) traumatic surgery resulting in large open surfaces
• Bleeding tendencies associated with active ulceration or overt bleeding of:
(1) gastrointestinal, genitourinary or respiratory tracts;
(2) cerebrovascular hemorrhage;
(3) aneurysms-cerebral, dissecting aorta;
(4) pericarditis and pericardial effusions;
(5) bacterial endocarditis
• Threatened abortion, eclampsia and pre-eclampsia
• Inadequate laboratory facilities
• Unsupervised patients with senility, alcoholism, or psychosis or other lack of patient co-operation
• Spinal puncture and other diagnostic or therapeutic procedures with potential for uncontrollable bleeding
• Miscellaneous: major regional and lumbar block anaesthesia, malignant hypertension and known hypersensitivity to warfarin or to any other component of this product.
PACKAGING INFORMATION
WARF-1 ..............Blister pack of 10 tablets
WARF-2 ..............Blister pack of 10 tablets
WARF-5 ..............Blister pack of 10 tablets
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