Precautions
The appropriate initial dosing of Coumadin varies widely for different patients. Not all factors responsible for warfarin dose variability are known, and the initial dose is influenced by: Clinical factors including age, race, body weight, sex, concomitant medications, and comorbidities
Why does the initial dose of Coumadin vary for different patients?
Going for regular Coumadin monitoring allows your doctor to ensure you are receiving the right Coumadin dose, reducing your risk of blood clots without an increased risk of extra bleeding.
Why do I need Coumadin monitoring?
Coumadin has a narrow therapeutic range - meaning that there is a fine line between too much and too little. For this reason, regular blood monitoring of the international normalized ratio (INR) - a standardized number that determines the ability of your blood to clot - is required.
What is the therapeutic range of Coumadin?
Coumadin Single-Scored Tablets Strength Color Superimposed Imprint 1 mg Pink 1 2 mg Lavender 2 2.5 mg Green 2-1/2 3 mg Tan 3 5 more rows ...
What is the strength of Coumadin single-scored tablets?
How do you monitor the effectiveness of warfarin?
If the dose of warfarin is too high, the patient may be at risk of serious bleeding. It can be monitored by drawing blood from a vein and sending the blood to an accredited laboratory to test, or it can be monitored by testing blood from a fingerstick with an INR test meter outside of a laboratory.
How do you know if Coumadin is effective?
The blood test, called prothrombin time (PT or protime), is used to calculate your International Normalized Ratio (INR). Your INR helps your healthcare provider determine how well warfarin is working to prevent blood clots and if the dose needs to be adjusted.
What two blood tests should be performed to determine the effectiveness of Coumadin?
For this reason, if you take Coumadin, you must go for regular blood tests that will measure how long it takes for your blood to clot. The test is called prothrombin time test, or protime (PT). The result of the PT is reported as the International Normalized Ratio (INR).
When checking the effectiveness of warfarin the nurse would check?
2.When a patient is taking warfarin, the nurse should closely monitor INR and PT levels to verify they are in normal range to prevent bleeding complications. Specifically, the therapeutic range for INR is between 2.0 to 3.5 depending upon the indication.
How do you read PT INR results?
In healthy people an INR of 1.1 or below is considered normal. An INR range of 2.0 to 3.0 is generally an effective therapeutic range for people taking warfarin for disorders such as atrial fibrillation or a blood clot in the leg or lung.
What lab values do you monitor with warfarin?
A PT/INR test is most often used to: See how well warfarin is working. Warfarin is a blood-thinning medicine that's used to treat and prevent dangerous blood clots.
Which of the following diagnostic tests is used to monitor the effectiveness of warfarin therapy?
The prothrombin time (PT) and the activated partial thromboplastin time (aPTT) are laboratory tests commonly used to monitor warfarin and heparin, respectively.
What is the difference between PT and PTT?
The prothrombin time (PT) test measures how quickly blood clots. The partial thromboplastin time (PTT) is mainly used to monitor a person's response to anticoagulant therapies.
What does aPTT measure?
The partial thromboplastin time (PTT; also known as activated partial thromboplastin time (aPTT)) is a screening test that helps evaluate a person's ability to appropriately form blood clots. It measures the number of seconds it takes for a clot to form in a sample of blood after substances (reagents) are added.
How often do you check INR on warfarin?
When you first start warfarin, you may need to have blood tests every few days or weekly. When your INR and warfarin dose are stable, blood tests are often done every 2 to 4 weeks, sometimes longer. If your dose changes you may need to have your INR tested more often.
What does the INR measure?
An INR test measures the time for the blood to clot. It is also known as prothrombin time, or PT. It is used to monitor blood-thinning medicines, which are also known as anticoagulants.
What assessment does a nurse do before she he administers the medication of warfarin?
Assess for signs of bleeding and hemorrhage (bleeding gums; nosebleed; unusual bruising; tarry, black stools; hematuria; fall in hematocrit or BP; guaiac-positive stools, urine, or nasogastric aspirate). Assess for evidence of additional or increased thrombosis.
How is Coumadin dose influenced?
The initial dose of Coumadin is influenced by age, race, body weight, sex, concomitant medications, and comorbidities.
How does coumadin work?
Coumadin (warfarin) works by blocking the formation of vitamin K-dependent clotting factors and inhibiting a vitamin K-dependent enzyme complex, as well as two anticoagulant proteins. This increases the time it takes for blood to clot.
How long to overlap heparin with coumadin?
Overlap Coumadin therapy with heparin for 4 to 5 days or until the desired INR has been reached. Should not be used as initial therapy in people with certain disorders, such as heparin-induced thrombocytopenia (HIT), although treatment may be considered after the platelet count has normalized.
How long does it take for Coumadin to work?
One dose of Coumadin lasts for 2 to 5 days; however, daily dosing is needed to keep blood levels consistent.
What is Coumadin used for?
Coumadin belongs to the class of drugs known as coumarins. Coumadin may also be called an anticoagulant. 2. Upsides. May be used to prevent and treat deep vein thrombosis (DVT) or pulmonary embolism (PE).
What enzymes are involved in metabolizing coumadin?
Coumadin is metabolized by several CYP450 enzymes, such as CYP2C9, 2C19, 2C8, 2C18, 1A2, and 3A4. Any inhibitor of CYP2C9, 1A2, or 3A4 has the potential to increase the effect of Coumadin (increase the INR). Any inducers of CYP2C9, 1A2, or 3A4 have the potential to decrease the effect of Coumadin (decrease the INR).
What foods can affect coumadin?
Avoid eating too much of the same thing (for example, a whole plate of broccoli or a big bowl of salad greens). Foods high in vitamin K include kale, collards, broccoli, spinach, and other green leafy vegetables. Cranberry juice and alcohol may also affect Coumadin levels so limit your intake of these.
What are the 4 variances in warfarin?
Overall, results identified 4 main variances related to warfarin therapy: 1) inappropriate administration of a warfarin loading dose, 2) inappropriate use of vitamin K, 3) inconsistent overlapping of heparin with warfarin, and 4) inconsistent provision of patient education.
How long does it take for warfarin to change INR?
The earliest changes in INR are typically seen 24 to 36 hours after administration of the dose. The antithrombotic effect of warfarin is not present ...
How long does it take for heparin to work?
Heparin displays an anticoagulant effect within 1 day, while the anticoagulant effects of warfarin are not evident until the third day of therapy. If rapid anticoagulant effects are needed, heparin should be initiated first, and warfarin should be started within a day or two.
How long does prothrombin last?
Because prothrombin has a half-life of around 50 hours, loading doses of warfarin are of limited value (4). In clinical practice, loading doses (e.g., 7.5 mg or more per day) of warfarin may increase the patient's risk of bleeding complications early in therapy by eliminating the production of functional factor VII (2, 5).
How much ACCP is induction?
The ACCP supports an “induction” dose (rather than a large loading dose) for initiation of therapy. This induction dose can range from 2 to 5 mg per day and is adjusted according to the patient's INR (1).
What is the treatment for venous thrombosis?
Warfarin, a vitamin K antagonist, is an oral anticoagulant indicated for the prevention and treatment of venous thrombosis and its extension and the prevention and treatment of the thromboembolic complications associated with atrial fibrillation.
What is the purpose of taking Coumadin?
Warfarin (brand names Coumadin and Jantoven) is a prescription medication used to prevent harmful blood clots from forming or growing larger. Beneficial blood clots prevent or stop bleeding, but harmful blood clots can cause a stroke, heart attack, deep vein thrombosis, or pulmonary embolism.
Why is warfarin called an anticoagulant?
Because warfarin interferes with the formation of blood clots, it is called an anticoagulant. Many people refer to anticoagulants as “blood thinners”; however, warfarin does not thin the blood but instead causes the blood to take longer to form a clot.
What is the purpose of Warfarin?
Warfarin (brand names Coumadin and Jantoven) is a prescription medication used to prevent harmful blood clots from forming or growing larger. Beneficial blood clots prevent or stop bleeding, but harmful blood clots can cause a stroke, heart attack, deep vein thrombosis, or pulmonary embolism.
What is the prothrombin time test?
On the basis of the results of the blood test, your daily dose of warfarin will be adjusted to keep your clotting time within a target range. The blood test used to measure the time it takes for blood to clot is referred to as a prothrombin time test, or protime (PT).
How often should I monitor INR?
It is important to monitor the INR (at least once a month and sometimes as often as twice weekly) to make sure that the level of warfarin remains in the effective range.
What is the goal of color coded doses?
The goal is to allow the patient to identify the color-coded dose and prevent mix-ups or errors. Therefore, if the color or dose of the dispensed tablet appears different from the pill taken previously, the patient should immediately notify the dispensing pharmacist or healthcare provider.
Does warfarin help with blood clots?
Warfarin decreases the body’s ability to form blood clots by blocking the formation of vitamin K–dependent clotting factors. Vitamin K is needed to make clotting factors and prevent bleeding. Therefore, by giving a medication that blocks the clotting factors, your body can stop harmful clots from forming and prevent clots from getting larger.
How long does Coumadin stay in your system?
If a patient misses a dose of Coumadin at the intended time of day, the patient should take the dose as soon as possible on the same day. The patient should not double the dose the next day to make up for a missed dose.
How does warfarin affect clotting factors?
Warfarin acts by inhibiting the synthesis of vitamin K-dependent clotting factors, which include Factors II, VII, IX, and X, and the anticoagulant proteins C and S. Vitamin K is an essential cofactor for the post ribosomal synthesis of the vitamin K-dependent clotting factors. Vitamin K promotes the biosynthesis of γ-carboxyglutamic acid residues in the proteins that are essential for biological activity. Warfarin is thought to interfere with clotting factor synthesis by inhibition of the C1 subunit of vitamin K epoxide reductase (VKORC1) enzyme complex, thereby reducing the regeneration of vitamin K 1 epoxide [see Clinical Pharmacology (12.5)].
What is the chemical name of warfarin?
Coumadin (warfarin sodium) tablets contain warfarin sodium, an anticoagulant that acts by inhibiting vitamin K‑dependent coagulation factors. The chemical name of warfarin sodium is 3- (α-acetonylbenzyl)-4-hydroxycoumarin sodium salt, which is a racemic mixture of the R - and S -enantiomers.
How long after heparin injection should INR be monitored?
As heparin may affect the INR, patients receiving both heparin and Coumadin should have INR monitoring at least: • 5 hours after the last intravenous bolus dose of heparin, or. • 4 hours after cessation of a continuous intravenous infusion of heparin, or. • 24 hours after the last subcutaneous heparin injection.
What is the goal of anticoagulant treatment?
Once a thrombus has occurred, however, the goals of anticoagulant treatment are to prevent further extension of the formed clot and to prevent secondary thromboembolic complications that may result in serious and possibly fatal sequelae.
How long does heparin therapy last?
To ensure therapeutic anticoagulation, continue full dose heparin therapy and overlap Coumadin therapy with heparin for 4 to 5 days and until Coumadin has produced the desired therapeutic response as determined by INR, at which point heparin may be discontinued.
Which gene variants explain the largest proportion of known variability in warfarin dose requirements?
VKORC1 and CYP2C9 gene variants generally explain the largest proportion of known variability in warfarin dose requirements. CYP2C9 and VKORC1 genotype information, when available, can assist in selection of the initial dose of warfarin [see Dosage and Administration (2.3)].
How It Works
This medication is used to treat blood clots (such as in deep vein thrombosis-DVT or pulmonary embolus-PE) and/or to prevent new clots from forming in your body.
May Treat: Cerebral thromboembolism · Deep vein thrombosis · Deep vein thrombosis with pulmonary embolism · Deep venous thrombosis · Myocardial reinfarction and more
Alternate Brand Names: Jantoven
Drug Class: Anticoagulants - Coumarin
Availability: Prescription Required
Pregnancy: Do not use. This medication may be harmful to an unborn child.
May Treat: Cerebral thromboembolism · Deep vein thrombosis · Deep vein thrombosis with pulmonary embolism · Deep venous thrombosis · Myocardial reinfarction and more
Alternate Brand Names: Jantoven
Drug Class: Anticoagulants - Coumarin
Availability: Prescription Required
Pregnancy: Do not use. This medication may be harmful to an unborn child.
Lactation: Does not adversely affect lactation
Alcohol: Limit intake while taking this medication
Driving: May cause drowsiness or dizziness. Use caution
Manufacturer: BMS
- Before use, important to read the Medication Guide
- Call MD NOW if persistent or severe bleeding occurs
- Do not take if pregnant contact your doctor
- Before use, important to read the Medication Guide
- Call MD NOW if persistent or severe bleeding occurs
- Do not take if pregnant contact your doctor
- Review all drugs you are taking with your doctor
- Tell doctor & dentist you are using this medicine
- No alcohol/aspirin-like meds. Ask MD re. aspirin.
- Maintain a balanced diet.
- Have your INR(PT) checked regularly. A Clotting test
Upsides
Downsides
Bottom Line
Tips
Response and Effectiveness
Interactions
- If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include: 1. Major and fatal bleeding. Bleeding is more likely to occur within the first month. 2. Other common side effects include gastrointestinal disturbances (such as nausea, vomiting, diarrhea, taste perversion, abdominal p…
References
- Coumadin is effective at "thinning the blood" (reducing the ability of the blood to clot); however, several factors can affect blood levels including diet, ethnicity, other medications, and illness...
Further Information
- Be aware that foods containing vitamin K can affect Coumadin therapy. Try to eat a normal, balanced diet so that you maintain a consistent intake of vitamin K. Avoid eating too much of the same thi...
- No one dosage fits all. The dosage schedule for Coumadin needs to be tailored for each person depending on their INR response to the drug and the condition being treated. Patient f…
- Be aware that foods containing vitamin K can affect Coumadin therapy. Try to eat a normal, balanced diet so that you maintain a consistent intake of vitamin K. Avoid eating too much of the same thi...
- No one dosage fits all. The dosage schedule for Coumadin needs to be tailored for each person depending on their INR response to the drug and the condition being treated. Patient factors such as ag...
- An initial lower starting dose of Coumadin is recommended for seniors or people who are frail or of Asian descent.
- Loading doses (a bigger dose at the start of treatment) are no longer routinely recommended as these increase the risk of bleeding without offering any more rapid protection against clot …