Coumadin and its Uses Generic Coumadin inhibits normal blood clotting (coagulation). Since Coumadin hinders the formation of blood clots, it is also called an "anticoagulant." Many people refer to these kinds of medicines as "blood thinners", although they do not actually cause the blood to become less thick, only less liable to clot.
Coumadin is often prescribed for patients with certain types of irregular heartbeat and after a heart attack or heart valve replacement surgery.
Generic Coumadin is used to treat or prevent harmful blood clots that may occur in the veins (venous thrombosis) or lungs (pulmonary embolism), or with a type of abnormal heartbeat (such as atrial fibrillation), or following a heart valve replacement. Coumadin is also used to reduce the risk of stroke and other problems in patients who have had a heart attack.
Generic Coumadin works by stopping the formation of substances that cause clots.
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Blood clots normally only form to stop bleeding that has occurred as a result of injury to the tissues. The clotting process is complicated and begins when blood cells called platelets clump together at the site of damage and produce chemicals that activate clotting factors in the blood. Clotting factors are proteins that are produced by the liver. Vitamin K is essential for their production. The activated clotting factors cause a protein called fibrin to be converted into another called fibrinogen. Fibrinogen binds the platelets together, forming a blood clot. This is the body's natural way of repairing itself.
Sometimes, however, a blood clot can form abnormally within the blood vessels. This is known as a thrombus and can be dangerous because the clot may detach and travel in the bloodstream, where it becomes known as an embolus. The clot may eventually get lodged in a blood vessel, thereby blocking the blood supply to a vital organ such as the heart, brain or lungs. This is known as a thromboembolism.
Some people have an increased tendency for blood clots to form within the blood vessels. This is usually due to a disturbance in the blood flow within the blood vessels. For example, fatty deposits on the walls of the blood vessels (atherosclerosis) can disrupt the blood flow, giving a tendency for platelets to clump together and start off the clotting process. Slow blood flow in the leg and pelvic veins can also result in clots forming (deep vein thrombosis). These clots can break off and travel to the lungs (pulmonary embolism). A type of fast irregular heartbeat called atrial fibrillation can also disrupt blood flow and may lead to blood clots forming in the heart. Heart valve disease can have the same effect, particularly if artificial heart valves have been fitted. Clots in the heart can detach and travel to the brain, causing a stroke. Coumadin is used to reduce the risk of blood clots forming inside the blood vessels in conditions such as these.
Coumadin works by preventing the vitamin K dependent production of the clotting factors described above. Coumadin prevents the production of these clotting factors by inhibiting the action of vitamin K. Without these clotting factors fibrin cannot be converted into fibrinogen and blood clots are therefore less likely to occur.
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Coumadin Dose Missed Dose
Take the missed dose as soon as you remember, on the same day. If the missed dose is not remembered until the next day, skip that dose and take only the next regularly scheduled dose. Never take a double dose of Coumadin.
Excess Dose of Coumadin
Coumadin in excess dose may show symptoms such as include bruising; small, broken blood vessels under the skin; excessive bleeding from cuts or wounds; bleeding from the gums; blood in the stools, urine, or vomit; and excessive menstrual bleeding in women.
Conditions for Storage of Coumadin
Store Coumadin at room temperature away from moisture and heat.
Potencies of Coumadin
Coumadin Tablets: Coumadin 1 mg, Coumadin 2 mg & Coumadin 5 mg
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Food and Drug Interactions with Coumadin
The following medicines may enhance the effect of Coumadin (increased INR; Coumadin dose may need reducing):
- allopurinol
- amiodarone
- antibiotic medicines (eg ampicillin, ciprofloxacin, co-trimoxazole, erythromycin, metronidazole)
- antifungal medicines (eg fluconazole, ketoconazole, miconazole)
- anabolic steroids (oxymetholone, stanozolol)
- aspirin (may also irritate the stomach lining, which can result in bleeding from the stomach or intestine in people taking warfarin)
- certain chemotherapy regimens
- cimetidine
- danazol
- dextropropoxyphene (found in co-proxamol/Distalgesic)
- diflunisal
- dipyridamole
- disulfiram
- fibrate medicines (eg bezafibrate, ciprofibrate, clofibrate)
- flutamide
- glucagon (large doses)
- Non-steroidal anti-inflammatory drugs (NSAIDs, particularly azapropazone, diclofenac, flurbiprofen, indometacin, phenylbutazone, piroxicam. NSAIDs may also irritate the stomach and intestinal lining, which can result in bleeding from the gut in people taking Coumadin. The interaction does not generally apply to NSAIDs applied to the skin.)
- omeprazole
- paracetamol (long-term regular use, occassional painkilling doses should not affect Coumadin significantly)
- propafenone
- rosuvastatin
- sulfinpyrazone
- tamoxifen
- thyroxine (levothyroxine)
- zafirlukast
- The following medicines may reduce the effect of Coumadin (decreased INR; warfarin dose may need increasing):
- aminoglutethimide
- azathioprine
- barbiturates, including phenobarbitone and primidone
- carbamazepine
- certain chemotherapy regimens
- colestyramine
- griseofulvin
- oestrogens
- progestogens
- raloxifene
- rifampicin
- sucralfate
- the herbal remeday St John's wort (Hypericum perforatum)
- vitamin K.
- The following medicines may also alter the effect of Coumadin and the dose of Coumadin may need to be adjusted up or down (as prothombin time may be increased or reduced by the following medicines):
- corticosteroids
- phenytoin
- quinidine
- ritonavir
- There may be an increased risk of bleeding if Coumadin is taken in combination with any of the following medicines.
- SSRI antidepressants such as paroxetine
- Antiplatelet or 'blood thinning' medicines such as aspirin, ticlopidine, dipyridamole
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Contraindications with Coumadin
Coumadin is contraindicated in the following:
- Severe kidney disease
- Severe liver disease
- Bacterial infection of the heart valves and the lining surrounding the heart (bacterial endocarditis)
- Uncontrolled high blood pressure (hypertension)
- Peptic ulcer
- Pregnancy
- Allergy to one or any of its ingredients
- Breastfeeding
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Precautions with Coumadin
Coumadin should be used with caution in:
- Elderly people
- Decreased kidney function
- People who have had recent surgery, bleeding or major injury
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Adverse effects with Coumadin
The adverse effects associated with Coumadin are:
- Bruising
- Increased tendency to bleed
- Diarrhoea
- Nausea and vomiting
- Rash
- Yellowing of the skin and eyes (jaundice)
- Hair loss (alopecia)
- Death of the skin cells (skin necrosis)
- Liver disorders
- Inflammation of the pancreas (pancreatitis)
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