Welcome to this video tutorial on coumadin.
Coumadin, or warfarin, is the most commonly used oral anti-coagulant drug, often called a blood thinner.
It is used to prevent blood clots in veins or arteries, reducing the risk of strokes and heart attacks.
Coumadin is given for long term prevention or management of venous thrombosis,
which is a blood clot in a vein, including DVT,
pulmonary embolism, which is a blockage of an artery in the lungs,
or embolisms associated with atrial fibrillation or prosthetic heart valves.
After a heart attack, coumadin is given to reduce the risk of a recurring heart attack, stroke and death.
Coumadin does not have a direct effect on an established thrombus, or blood clot,
but once a thrombus has occurred the goal is to prevent secondary complications that may result.
Several proteins called coagulation factors are involved in the process that the body
uses to form blood clots to control bleeding.
When an injury occurs, and bleeding begins, coagulation factors are activated in a sequence of steps
called the coagulation cascade that eventually helped to form a clot.
The goal of warfarin therapy is to maintain a balance between preventing clots
and causing excessive bleeding.
This balance requires careful monitoring of the patient's PT, or prothrombin time,
and INR, international normalized ratio.
The PT measures the number of seconds it takes blood plasma to clot.
It is usually performed with a partial thermoplastic time, or PTT,
and together they assess the amount and function of coagulation factors.
The INR is a calculation based on results of the PT
and is used to monitor patients on warfarin therapy.
The normal therapy range is two to three, with a high INR indicating a higher risk of bleeding,
and a low INR suggesting a higher risk of developing a clot.
The INR can be used to adjust the patient's drug dosage to get the PT into the desired range.
When starting warfarin, PT and INR should be assessed daily until a stable daily dose is reached.
That is the dose that maintains the PT and INR within the therapeutic ranges and does not cause bleeding.
From then on PT and INR are checked every two to four weeks as long as drug therapy is continued.
The most common adverse effect of coumadin is bleeding.
Occurring anywhere in the body spontaneously or in response to a minor trauma.
Bleeding complications may present as severe bleeding, including heavier than normal menstrual bleeding,
inexplicable bruising, blood in urine which causes it to be red or brown in color,
blood in the stool causing it to be black or bloody,
vomiting blood which sometimes looks like coffee grounds,
a bloody nose or gums which are seen when brushing the teeth.
Severe headache, pain in the chest, abdomen, joint, muscle, or other area,
dizziness or weakness, hypotension,
unexplained swelling, shortness of breath or unexplained shock,
and bleeding sites may also involve surgical wounds, skin lesions, or injection sites.
The most tragic bleeding involves the brain and spinal cord.
Some less common adverse effects of coumadin include the following:
several studies have shown a decrease in bone mineral density leading to osteoporosis,
thought to be linked to a reduced intake of Vitamin K which is necessary for bone health.
Side effects involving the skin include dermatitis, alopecia which is hair loss and purple toes syndrome,
where the toes are painful and look purple or dark.
Warfarin induced skin necrosis is a rare but serious complication,
usually occurring when warfarin treatment is initiated in a patient with protein C deficiency,
which is a naturally occurring anti-coagulant.
Warfarin can cause major or fatal bleeding, which is more likely to occur when the medication
is first started or if too much warfarin is taken.
Risk factors for bleeding include the following:
age 65 years or older, highly variable INRs,
history of GI bleeding, hypertension, cerebral vascular disease,
serious heart disease, anemia, malignancy, trauma,
renal insufficiency, a similar drug taken at the same time,
or a long duration of warfarin therapy.
Warfarin should not be given to patients with GI ulcerations,
blood disorders associated with bleeding, severe kidney or liver disease, severe hypertension,
recent surgery of the eye, spinal cord, or brain, and during pregnancy.
It should be used cautiously in patients with mild hypertension, renal or hepatic disease,
alcoholism, a history of GI ulcerations,
drainage tubes such as an NG tube or urinary catheter,
and occupations with high risks of traumatic injury.
There are several drugs that increase the effects of warfarin, including
analgesics, such as Tylenol, Aspirin and NSAIDs,
Androgens and anabolic steroids, antibacterial drugs,
antifungal drugs, antiseizure drugs, cardiovascular drugs, GI drugs and thyroid medications.
There are other drugs that decrease the effects of warfarin including:
antacids, diuretics, estrogens, including oral contraceptives
and Vitamin K, which is the antidote for warfarin overdosage.
Alcohol may increase or decrease the effects of warfarin, depending on the state of the
liver and the rate of metabolism.
Therefore, it is extremely important for the health care provider giving warfarin to be
aware of all medications the patient is taking,
as well as herbal and dietary supplements
as they can also have a profound effect on warfarin.
Vitamin K is in most multivitamin supplements and should be taken consistently to avoid
fluctuating Vitamin K levels.
Vitamin C in excess of 500 milligrams per day may lower the INR,
and vitamin E in excess of 400 IU per day may increase warfarin effects.
Herbs that may increase the effects of warfarin include: alfalfa, celery, clove, feverfew,
garlic, ginger, gingko, ginseng and licorice.
Eating a normal balanced diet is important for the patient taking coumadin,
because changes in the diet can affect the coumadin therapy.
For example, too much Vitamin K can lower the effective of coumadin since Vitamin K
is involved in the body's clotting process.
There is no need to avoid foods with vitamin K,
but it is best to maintain a consistent level of consumption of the products,
and to be aware of foods with vitamin K so overconsumption does not occur.
Foods rich in Vitamin K include: green leafy vegetables, beef liver, broccoli, brussels sprouts,
soybeans, avocados, asparagus, dill pickles,
green peas, green tea, canola, olive and soybean oil, margarine and mayonnaise.
Here are some nursing tips when caring for the patient on coumadin therapy.
The goal is to implement safety measures to prevent trauma and bleeding.
The following are important in the inpatient setting.
Keep the call light in reach and assist with ambulation to prevent falling.
Provide an electric razor for shaving,
avoid IM injections, venipunctures and arterial punctures when possible.
Avoid intubations when possible such as NG tubes and urinary catheters.
The patient at home needs to be reminded to take coumadin exactly as prescribed.
If it does is missed take as soon as possible on the same day, but do not take a double
dose the next day to make up for the missed dose.
Have regular blood tests and visits with the health care provider
and call the health care provider right away if too much coumadin is has taken,
if they are sick with diarrhea, infection or fever,
or if they have a fall or injury, especially if they hit their head.
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