Healthy Heart Resources
Featured Centers
- Eating Out? Cut Calories, Heartburn
- 5 Good Ways to Save Money on Medicine
- 8 Ways to Treat Your Allergies
home > drugs a-z list > coumadin (warfarin sodium) drug center > coumadin (warfarin sodium) drug - side effects and drug interactions
Recommended Topic Related To:
Coumadin
Introduction to Arrhythmia
An irregular heartbeat is an arrhythmia (also called dysrhythmia). Heart rates can also be irregular. A normal heart rate is 50 to 100 beats per minute. Arrhythmias and abnormal heart rates don't necessarily occur together. Arrhythmias can occur with a normal heart rate, or with heart rates that are slow (called bradyarrhythmias -- less than 50 beats per minute). Arrhythmias can also occur with rapid heart rates (called tachyarrhythmias -- faster than 100 beats per minute). In the United States, more than 850,000 people are hospitalized for an arrhythmia each year.
What causes an arrhythmia?
Arrhythmias may be caused by many different factors, including:
- Coronary artery disease.
- Electrolyte imbalances in your blood (such as sodium or potassium).
- Changes in your heart muscle.
- Injury from a heart attack.
- Healing process after heart surgery.
- Irregula...
Coumadin
|
|
SIDE EFFECTS
Potential adverse reactions to COUMADIN (warfarin sodium) may include:
- Fatal or nonfatal hemorrhage from any tissue or organ. This is a consequence of the anticoagulant effect. The signs, symptoms, and severity will vary according to the location and degree or extent of the bleeding. Hemorrhagic complications may present as paralysis; paresthesia; headache, chest, abdomen, joint, muscle or other pain; dizziness; shortness of breath, difficult breathing or swallowing; unexplained swelling; weakness; hypotension; or unexplained shock. Therefore, the possibility of hemorrhage should be considered in evaluating the condition of any anticoagulated patient with complaints which do not indicate an obvious diagnosis. Bleeding during anticoagulant therapy does not always correlate with PT/INR. (See OVERDOSAGE: Treatment.)
- Bleeding which occurs when the PT/INR is within the therapeutic range warrants diagnostic investigation since it may unmask a previously unsuspected lesion, eg, tumor, ulcer, etc.
- Necrosis of skin and other tissues. (See WARNINGS.)
- Adverse reactions reported infrequently include: hypersensitivity/allergic reactions, including anaphylactic reactions, systemic cholesterol microembolization, purple toes syndrome, hepatitis, cholestatic hepatic injury, jaundice, elevated liver enzymes, hypotension, vasculitis, edema, anemia, pallor, fever, rash, dermatitis, including bullous eruptions, urticaria, angina syndrome, chest pain, abdominal pain including cramping, flatulence/bloating, fatigue, lethargy, malaise, asthenia, nausea, vomiting, diarrhea, pain, headache, dizziness, loss of consciousness, syncope, coma, taste perversion, pruritus, alopecia, cold intolerance, and paresthesia including feeling cold and chills.
Rare events of tracheal or tracheobronchial calcification have been reported in association with long-term warfarin therapy. The clinical significance of this event is unknown.
Priapism has been associated with anticoagulant administration; however, a causal relationship has not been established.
DRUG INTERACTIONS
Drug-Drug and Drug-Disease Interactions
It is generally good practice to monitor the patient's response with additional PT/INR determinations in the period immediately after discharge from the hospital, and whenever other medications, including botanicals, are initiated, discontinued or taken irregularly. The following factors are listed for reference; however, other factors may also affect the anticoagulant response.
Drugs may interact with COUMADIN (warfarin sodium) through pharmacodynamic or pharmacokinetic mechanisms. Pharmacodynamic mechanisms for drug interactions with COUMADIN (warfarin sodium) are synergism (impaired hemostasis, reduced clotting factor synthesis), competitive antagonism (vitamin K), and altered physiologic control loop for vitamin K metabolism (hereditary resistance). Pharmacokinetic mechanisms for drug interactions with COUMADIN (warfarin sodium) are mainly enzyme induction, enzyme inhibition, and reduced plasma protein binding. It is important to note that some drugs may interact by more than one mechanism.
The following factors, alone or in combination, may be responsible for INCREASED PT/INR response:
ENDOGENOUS FACTORS:
| blood dyscrasias see CONTRAINDICATIONS cancer collagen vascular disease congestive heart failure |
diarrhea elevated temperature hepatic disorders infectious hepatitis jaundice |
hyperthyroidism poor nutritional state steatorrhea vitamin K deficiency |
EXOGENOUS FACTORS:
Potential drug interactions with COUMADIN (warfarin sodium) are listed below by drug class and by specific drugs.
| Classes of Drugs | ||
| 5-lipoxygenase Inhibitor Adrenergic Stimulants, Central Alcohol Abuse Reduction Preparations Analgesics Anesthetics, Inhalation Antiandrogen Antiarrhythmics† Antibiotics† Aminoglycosides (oral) Cephalosporins, parenteral Macrolides Miscellaneous Penicillins, intravenous, high dose Quinolones (fluoroquinolones) Sulfonamides, long acting Tetracyclines Anticoagulants Anticonvulsants† Antidepressants† Antimalarial Agents Antineoplastics† Antiparasitic/Antimicrobials |
Antiplatelet Drugs/Effects Antithyroid Drugs† Beta-Adrenergic Blockers Cholelitholytic Agents Diabetes Agents, Oral Diuretics† Fungal Medications, Intravaginal, Systemic† Gastric Acidity and Peptic Ulcer Agents† Gastrointestinal Prokinetic Agents Ulcerative Colitis Agents Gout Treatment Agents Hemorrheologic Agents Hepatotoxic Drugs Hyperglycemic Agents Hypertensive Emergency Agents Hypnotics† Hypolipidemics† Bile Acid-Binding Resins† Fibric Acid Derivatives HMG-CoA Reductase Inhibitors† |
Leukotriene Receptor Antagonist Monoamine Oxidase Inhibitors Narcotics, prolonged Nonsteroidal Anti-Inflammatory Agents Proton Pump Inhibitors Psychostimulants Pyrazolones Salicylates Selective Serotonin Reuptake Inhibitors Steroids, Adrenocortical† Steroids, Anabolic (17-Alkyl Testosterone Derivatives) Thrombolytics Thyroid Drugs Tuberculosis Agents† Uricosuric Agents Vaccines Vitamins† |
| Specific Drugs Reported | ||
| acetaminophen alcohol† allopurinol aminosalicylic acid amiodarone HCl argatroban aspirin atenolol atorvastatin† azithromycin bivalirudin capecitabine cefamandole cefazolin cefoperazone cefotetan cefoxitin ceftriaxone celecoxib cerivastatin chenodiol chloramphenicol chloral hydrate† chlorpropamide cholestyramine† cimetidine ciprofloxacin cisapride clarithromycin clofibrate COUMADIN (warfarin sodium) overdose cyclophosphamide† danazol dextran dextrothyroxine diazoxide diclofenac dicumarol diflunisal disulfiram doxycycline erythromycin esomeprazole ethacrynic acid ezetimibe |
fenofibrate fenoprofen fluconazole fluorouracil fluoxetine flutamide fluvastatin fluvoxamine gefitinib gemfibrozil glucagon halothane heparin ibuprofen ifosfamide indomethacin influenza virus vaccine itraconazole ketoprofen ketorolac lansoprazole lepirudin levamisole levofloxacin levothyroxine liothyronine lovastatin mefenamic acid methimazole† methyldopa methylphenidate methylsalicylate ointment (topical) metronidazole miconazole (intravaginal, oral, systemic) moricizine hydrochloride† nalidixic acid naproxen neomycin norfloxacin ofloxacin olsalazine omeprazole oxandrolone oxaprozin |
oxymetholone pantoprazole paroxetine penicillin G, intravenous pentoxifylline phenylbutazone phenytoin† piperacillin piroxicam pravastatin† prednisone† propafenone propoxyphene propranolol propylthiouracil† quinidine quinine rabeprazole ranitidine† rofecoxib sertraline simvastatin stanozolol streptokinase sulfamethizole sulfamethoxazole sulfinpyrazone sulfisoxazole sulindac tamoxifen tetracycline thyroid ticarcillin ticlopidine tissue plasminogen activator (t-PA) tolbutamide tramadol trimethoprim/sulfamethoxazole urokinase valdecoxib valproate vitamin E zafirlukast zileuton |
| also: other medications affecting blood elements
which may modify hemostasis dietary deficiencies prolonged hot weather unreliable PT/INR determinations †Increased and decreased PT/INR responses have been reported. |
||
The following factors, alone or in combination, may be responsible for DECREASED PT/INR response:
ENDOGENOUS FACTORS:
| edema hereditary coumarin resistance hyperlipemia |
hypothyroidism nephrotic syndrome |
EXOGENOUS FACTORS:
Potential drug interactions with COUMADIN (Warfarin Sodium) are listed below by drug class and by specific drugs.
| Classes of Drugs | ||
| Adrenal Cortical Steroid Inhibitors Antacids Antianxiety Agents Antiarrhythmics† Antibiotics† Anticonvulsants† Antidepressants† Antihistamines Antineoplastics† Antipsychotic Medications |
Antithyroid Drugs† Barbiturates Diuretics† Enteral Nutritional Supplements Fungal Medications, Systemic† Gastric Acidity and Peptic Ulcer Agents† Hypnotics† Hypolipidemics† Bile Acid-Binding Resins† HMG-CoA Reductase Inhibitors† |
Immunosuppressives Oral Contraceptives, Estrogen Containing Selective Estrogen Receptor Modulators Steroids, Adrenocortical† Tuberculosis Agents† Vitamins† |
| Specific Drugs Reported | ||
| alcohol† aminoglutethimide amobarbital atorvastatin† azathioprine butabarbital butalbital carbamazepine chloral hydrate† chlordiazepoxide chlorthalidone cholestyramine† clozapine corticotropin cortisone |
COUMADIN (warfarin sodium) under dosage cyclophosphamide† dicloxacillin ethchlorvynol glutethimide griseofulvin haloperidol meprobamate 6-mercaptopurine methimazole† moricizine hydrochloride† nafcillin paraldehyde pentobarbital |
phenobarbital phenytoin† pravastatin† prednisone† primidone propylthiouracil† raloxifene ranitidine† rifampin secobarbital spironolactone sucralfate trazodone vitamin C (high dose) vitamin K |
| also: diet high in vitamin K unreliable PT/INR determinations †Increased and decreased PT/INR responses have been reported. |
||
Because a patient may be exposed to a combination of the above factors, the net effect of COUMADIN (warfarin sodium) on PT/INR response may be unpredictable. More frequent PT/INR monitoring is therefore advisable. Medications of unknown interaction with coumarins are best regarded with caution. When these medications are started or stopped, more frequent PT/INR monitoring is advisable.
It has been reported that concomitant administration of warfarin and ticlopidine may be associated with cholestatic hepatitis.
Botanical (Herbal) Medicines
Caution should be exercised when botanical medicines (botanicals) are taken concomitantly with COUMADIN (warfarin sodium) . Few adequate, well-controlled studies exist evaluating the potential for metabolic and/or pharmacologic interactions between botanicals and COUMADIN (warfarin sodium) . Due to a lack of manufacturing standardization with botanical medicinal preparations, the amount of active ingredients may vary. This could further confound the ability to assess potential interactions and effects on anticoagulation. It is good practice to monitor the patient's response with additional PT/INR determinations when initiating or discontinuing botanicals.
Specific botanicals reported to affect COUMADIN (warfarin sodium) therapy include the following:
- Bromelains, danshen, dong quai (Angelica sinensis), garlic, Ginkgo biloba, ginseng, and cranberry products are associated most often with an INCREASE in the effects of COUMADIN (warfarin sodium) .
- Coenzyme Q10 (ubidecarenone) and St. John's wort are associated most often with a DECREASE in the effects of COUMADIN (warfarin sodium) .
Some botanicals may cause bleeding events when taken alone (eg, garlic and Ginkgo biloba) and may have anticoagulant, antiplatelet, and/or fibrinolytic properties. These effects would be expected to be additive to the anticoagulant effects of COUMADIN (warfarin sodium) . Conversely, other botanicals may have coagulant properties when taken alone or may decrease the effects of COUMADIN (warfarin sodium) .
Some botanicals that may affect coagulation are listed below for reference; however, this list should not be considered all-inclusive. Many botanicals have several common names and scientific names. The most widely recognized common botanical names are listed.
| Botanicals that contain coumarins with potential anticoagulant effects: | ||
| Agrimony1 Alfalfa Angelica (Dong Quai) Aniseed Arnica Asafoetida Bogbean2 Boldo Buchu Capsicum3 Cassia4 |
Celery Chamomile (German and Roman) Dandelion4 Fenugreek Horse Chestnut Horseradish Licorice4 Meadowsweet2 Nettle Parsley |
Passion Flower Prickly Ash (Northern) Quassia Red Clover Sweet Clover Sweet Woodruff Tonka Beans Wild Carrot Wild Lettuce |
| Miscellaneous botanicals with anticoagulant properties: | |
| Bladder Wrack (Fucus) |
Pau d'arco |
| Botanicals that contain salicylate and/or have antiplatelet properties: | ||
| Agrimony1 Aloe Gel Aspen Black Cohosh Black Haw Bogbean2 Cassia4 Clove |
Dandelion4 Feverfew Garlic5 German Sarsaparilla Ginger Ginkgo Biloba Ginseng (Panax)5 Licorice4 |
Meadowsweet2 Onion5 Policosanol Poplar Senega Tamarind Willow Wintergreen |
| Botanicals with fibrinolytic properties: | ||
| Bromelains Capsicum3 |
Garlic5 Ginseng (Panax)5 |
Inositol Nicotinate Onion5 |
| Botanicals with coagulant properties: | |
| Agrimony1 Goldenseal |
Mistletoe Yarrow |
1Contains coumarins, has antiplatelet properties, and may have coagulant
properties due to possible vitamin K content.
2Contains coumarins and salicylate.
3Contains coumarins and has fibrinolytic properties.
4Contains coumarins and has antiplatelet properties. 5Has antiplatelet
and fibrinolytic properties.
Effect on Other Drugs
Coumarins may also affect the action of other drugs. Hypoglycemic agents (chlorpropamide and tolbutamide) and anticonvulsants (phenytoin and phenobarbital) may accumulate in the body as a result of interference with either their metabolism or excretion.
Considerations for Increased Bleeding Risk
COUMADIN (warfarin sodium) is a narrow therapeutic range (index) drug, and additional caution should be observed when warfarin sodium is administered to certain patients. Reported risk factors for bleeding include high intensity of anticoagulation (INR > 4.0), age ≥ 65, highly variable INRs, history of gastrointestinal bleeding, hypertension, cerebrovascular disease, serious heart disease, anemia, malignancy, trauma, renal insufficiency, concomitant drugs (see PRECAUTIONS), and long duration of warfarin therapy. Identification of risk factors for bleeding and certain genetic variations in CYP2C9 and VKORC1 in a patient may increase the need for more frequent INR monitoring and the use of lower warfarin doses (see CLINICAL PHARMACOLOGY: Pharmacokinetics: Metabolism and DOSAGE AND ADMINISTRATION). Bleeding is more likely to occur during the starting period and with a higher dose of COUMADIN (warfarin sodium) (resulting in a higher INR).
Intramuscular (IM) injections of concomitant medications should be confined to the upper extremities which permits easy access for manual compression, inspections for bleeding and use of pressure bandages.
Caution should be observed when COUMADIN (warfarin sodium) (or warfarin) is administered concomitantly with nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, to be certain that no change in anticoagulation dosage is required. In addition to specific drug interactions that might affect PT/INR, NSAIDs, including aspirin, can inhibit platelet aggregation, and can cause gastrointestinal bleeding, peptic ulceration and/or perforation.
REFERENCES
14. COUMADIN (warfarin sodium) Medication Guide. Princeton, NJ: Bristol-Myers Squibb Company; 20XX.
Last reviewed on RxList: 1/3/2011
This monograph has been modified to include the generic and brand name in many instances.
Next: Drug Description
Additional Coumadin Information
Coumadin - User Reviews
Coumadin User Reviews
Now you can gain knowledge and insight about a drug treatment with Patient Discussions.
Here is a collection of user reviews for the medication Coumadin sorted by most helpful.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Heart Health
Get the latest treatment options.
From WebMD
Coumadin
Related Drugs
Health Resources
Related Supplements
Use it Now
Find it Now
Pill Identifier on RxList
- quick,
easy,
concise
Find a Local Pharmacy
- including
24 hour
pharmacies
Updated & New
RxList does not provide medical advice, diagnosis or treatment.