Pronunciation:

WAR-far-in

Brand Names:

• Coumadin

Dosage Forms:

• Powder for Solution

Warnings:

Warfarin can cause major or fatal bleeding. Regular monitoring of INR should be performed on all treated patients. Drugs, dietary changes, and other factors affect INR levels achieved with warfarin sodium therapy. Instruct patients about prevention measures to minimize risk of bleeding and to report signs and symptoms of bleeding .

Classifications:

Therapeutic—

Anticoagulant

Chemical—

Coumarin (class)

Uses of This Medicine:

Warfarin injection is used to prevent or treat blood clots such as deep venous thrombosis or pulmonary embolism. It is also used for blood clots that may be caused by certain heart conditions, open-heart surgery, or after a heart attack. Warfarin is an anticoagulant (blood thinner) that decreases the clotting ability of the blood.

This medicine is to be given only by or under the direct supervision of your doctor.

Before Using This Medicine:

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies—

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children—

Appropriate studies have not been performed on the relationship of age to the effects of warfarin injection in the pediatric population. Safety and efficacy have not been established.

Older adults—

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of warfarin injection in the elderly. However, elderly patients may require caution and an adjustment in the dose, especially those who are at risk of bleeding.

Breast-feeding—

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Other medicines—

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Amifampridine
• Tamoxifen

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Abciximab
• Aceclofenac
• Acenocoumarol
• Alefacept
• Alipogene Tiparvovec
• Alteplase, Recombinant
• Amiodarone
• Amoxicillin
• Ampicillin
• Anagrelide
• Anistreplase
• Apixaban
• Aprepitant
• Aspirin
• Azithromycin
• Bivalirudin
• Blinatumomab
• Capecitabine
• Carbenicillin
• Carboplatin
• Cefadroxil
• Cefdinir
• Cefepime
• Cefixime
• Cefotaxime
• Cefpodoxime
• Ceftazidime
• Ceftibuten
• Ceftizoxime
• Celecoxib
• Cephalexin
• Cephalothin
• Cephapirin
• Cephradine
• Ceritinib
• Chamomile
• Ciprofloxacin
• Citalopram
• Clarithromycin
• Clopidogrel
• Cloxacillin
• Cobicistat
• Collagenase, Clostridium histolyticum
• Cyclophosphamide
• Dabigatran Etexilate
• Dabrafenib
• Dalteparin
• Danaparoid
• Dapsone
• Deferasirox
• Desvenlafaxine
• Diclofenac
• Dicloxacillin
• Dihydroartemisinin
• Dipyridamole
• Doxifluridine
• Doxorubicin
• Doxorubicin Hydrochloride Liposome
• Dronedarone
• Drotrecogin Alfa
• Econazole
• Edoxaban
• Efavirenz
• Elvitegravir
• Enoxacin
• Enoxaparin
• Entacapone
• Enzalutamide
• Eptifibatide
• Erlotinib
• Erythromycin
• Escitalopram
• Etoposide
• Etravirine
• Fenofibrate
• Fenofibric Acid
• Fish Oil
• Fluconazole
• Fluorouracil
• Fluoxetine
• Fluvoxamine
• Garlic
• Gatifloxacin
• Gemifloxacin
• Ginkgo
• Golimumab
• Iloprost
• Imatinib
• Infliximab
• Influenza Virus Vaccine
• Itraconazole
• Ketoconazole
• Ketoprofen
• Leflunomide
• Lepirudin
• Levofloxacin
• Levomilnacipran
• Lomitapide
• Lycium barbarum
• Marijuana
• Mechlorethamine
• Mercaptopurine
• Methicillin
• Methotrexate
• Methyl Salicylate
• Metronidazole
• Miconazole
• Milnacipran
• Mirtazapine
• Moxalactam
• Moxifloxacin
• Nafcillin
• Nalidixic Acid
• Naproxen
• Nilotinib
• Nintedanib
• Nitisinone
• Norfloxacin
• Noscapine
• Ofloxacin
• Oritavancin
• Oseltamivir
• Oxacillin
• Oxandrolone
• Papaya
• Paroxetine
• Peginterferon Alfa-2b
• Penicillin G
• Penicillin V
• Pentosan Polysulfate Sodium
• Phenindione
• Phenprocoumon
• Piperacillin
• Pixantrone
• Posaconazole
• Prasugrel
• Procarbazine
• Proguanil
• Reteplase, Recombinant
• Rivaroxaban
• Ropinirole
• Roxithromycin
• Secukinumab
• Sertraline
• Siltuximab
• Simvastatin
• Sitaxsentan
• St John's Wort
• Streptokinase
• Sulfamethoxazole
• Sulfisoxazole
• Sultamicillin
• Tan-Shen
• Tegafur
• Telithromycin
• Tenecteplase
• Teriflunomide
• Testosterone
• Ticarcillin
• Ticlopidine
• Tinzaparin
• Tirofiban
• Torsemide
• Treprostinil
• Urokinase
• Valproic Acid
• Venlafaxine
• Vilazodone
• Vincristine
• Vincristine Sulfate Liposome
• Vindesine
• Vorapaxar
• Vortioxetine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Acarbose
• Acemetacin
• Acetaminophen
• Allopurinol
• Aminoglutethimide
• Amitriptyline
• Amprenavir
• Apazone
• Argatroban
• Atovaquone
• Avocado
• Azathioprine
• Balsalazide
• Bee Pollen
• Benzbromarone
• Bosentan
• Bromfenac
• Butabarbital
• Butalbital
• Carbamazepine
• Cefamandole
• Cefazolin
• Ceftriaxone
• Chitosan
• Chloral Hydrate
• Chlorthalidone
• Cholestyramine
• Chondroitin
• Cimetidine
• Cisapride
• Cisplatin
• Coenzyme Q10
• Colesevelam
• Curcumin
• Cyclosporine
• Danazol
• Desogestrel
• Dexamethasone
• Dexlansoprazole
• Dienogest
• Diflunisal
• Disopyramide
• Disulfiram
• Dong Quai
• Doxepin
• Drospirenone
• Duloxetine
• Eslicarbazepine Acetate
• Esomeprazole
• Estradiol Cypionate
• Estradiol Valerate
• Eterobarb
• Ethinyl Estradiol
• Ethynodiol Diacetate
• Etonogestrel
• Exenatide
• Felbamate
• Fluoxymesterone
• Fluvastatin
• Gefitinib
• Gemcitabine
• Gemfibrozil
• Ginger
• Ginseng
• Glucosamine
• Glyburide
• Griseofulvin
• Heparin
• Ifosfamide
• Indomethacin
• Indoprofen
• Isoniazid
• Isoxicam
• Ivermectin
• Lactulose
• Lansoprazole
• Levamisole
• Levonorgestrel
• Lixisenatide
• Lopinavir
• Lornoxicam
• Medroxyprogesterone Acetate
• Melatonin
• Meloxicam
• Menthol
• Mephobarbital
• Mesalamine
• Mesna
• Mestranol
• Methyltestosterone
• Mitotane
• Moricizine
• Nelfinavir
• Nevirapine
• Niacin
• Nilutamide
• Nimesulide
• Norelgestromin
• Norethindrone
• Norgestimate
• Norgestrel
• Omeprazole
• Oxyphenbutazone
• Oxypurinol
• Pantoprazole
• Parecoxib
• Pentoxifylline
• Phenobarbital
• Phenylbutazone
• Phytonadione
• Piracetam
• Prednisone
• Primidone
• Propafenone
• Propoxyphene
• Quetiapine
• Ranitidine
• Rifabutin
• Rifampin
• Ritonavir
• Rofecoxib
• Rosuvastatin
• Saquinavir
• Secobarbital
• Sorafenib
• Soybean
• Soy Isoflavones
• Soy Protein
• Stanozolol
• Sucralfate
• Sulfasalazine
• Sulfinpyrazone
• Sulindac
• Tenidap
• Terbinafine
• Tibolone
• Tigecycline
• Tolterodine
• Tramadol
• Trastuzumab
• Valdecoxib
• Vancomycin
• Vemurafenib
• Vitamin A
• Vitamin E
• Vorinostat
• Zafirlukast
• Zileuton

Other interactions—

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Cranberry Juice
• Pomegranate
• Tobacco

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Black Tea
• Green Tea
• High Protein Food
• Noni Juice
• Vitamin K Containing Food

Other medical problems—

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Blood disease or bleeding problems or
• Heart infection or
• Spinal anesthesia, recent or
• Stomach or intestinal ulcer, active or
• Stroke, history of or
• Surgery, recent or scheduled (eg, surgery of the eye, brain, or spine) or
• Threatened miscarriage—Should not be used in patients with these conditions. The risk of bleeding from warfarin may be increased.

• Catheter insertion or
• Congestive heart failure or
• Deep venous thrombosis, heparin-induced or
• Diabetes or
• Falls or blows to the body or head or
• Hypertension (high blood pressure) or
• Infection or
• Kidney disease or
• Liver disease or
• Major surgery, any type or
• Protein C deficiency (rare hereditary disease), known or suspected or
• Thrombocytopenia, heparin-induced or
• Trauma—Use with caution. May cause side effects to become worse.

Proper Use of This Medicine:

A nurse or other trained health professional will give you this medicine. This medicine is given through a needle placed in one of your veins.

Your doctor will only give you a few doses of this medicine and then switch you to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor.

Carefully follow your doctor's instructions about any special diet. This medicine works best when you eat about the same amount of vitamin K in your food every day. Tell your doctor before changing your diet. Avoid big changes in how much vitamin K you eat. Some foods that have a high amount of vitamin K are asparagus, broccoli, brussels sprouts, cabbage, green leafy vegetables (such as collards, turnip greens, mustard greens, spinach, and salad greens), plums, rhubarb, and certain vegetable oils (such as soybean oil and canola oil).

Precautions While Using This Medicine:

It is very important that your doctor check your progress at regular visits to see if the medicine is working properly. Blood tests, such as an INR, are needed to check for proper dosage and unwanted side effects. Be sure to keep all appointments.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant during treatment and for at least 1 month after the last dose. If you think you have become pregnant while using the medicine, tell your doctor right away.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before having surgery or medical tests.

Check with your doctor immediately if you have diarrhea, fever, or any symptoms of an infection.

This medicine may cause skin necrosis or gangrene. Call your doctor right away if you have pain, a color change, or a temperature change to any area of your body. Call your doctor right away if you have pain in your toes and they look purple or dark in color. These could be signs of a serious medical problem.

This medicine may increase your chance of bleeding. Check with your doctor right away if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin. Avoid picking your nose. If you need to blow your nose, blow it gently.

Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.

Be careful not to cut yourself when you are using sharp objects, such as a safety razor or fingernail or toenail cutters. Avoid contact sports or other situations where bruising or injury could occur.

It is recommended that you carry identification that says you are using warfarin. If you have any questions about what kind of identification to carry, check with your doctor.

Do not stop taking any of your medicines or start any new prescription or over-the-counter (OTC) medicines unless they have been discussed with your doctor. Keep a list of your medicines with you at all times. This includes prescription medicines, nonprescription (over-the-counter [OTC]) medicines, and herbal or vitamin supplements.

Side Effects of This Medicine:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Less common

Abdominal or stomach pain with cramping

bleeding gums

blood in the urine

bloody stools

blurred vision

burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

chest pain or discomfort

confusion

coughing up blood

difficulty with breathing or swallowing

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

excessive bruising

headache

increased menstrual flow or vaginal bleeding

nosebleeds

paralysis

peeling of the skin

prolonged bleeding from cuts

red or black, tarry stools

red or dark brown urine

sweating

unexplained swelling

unusual tiredness or weakness

Rare

Arm, back, or jaw pain

blue-green to black skin discoloration

blue or purple toes

change in consciousness

chest tightness or heaviness

chills

clay-colored stools

diarrhea

dizziness

fainting or loss of consciousness

fast or irregular breathing

fast or irregular heartbeat

fever

itching or skin rash

light-colored stools

loss of appetite

nausea and vomiting

pain in the toes

pain, redness, or sloughing of the skin

pale skin

skin blisters

small red or purple spots on the skin

stomach pain

swelling of the eyes or eyelids

tightness in the chest

troubled breathing with exertion

unpleasant breath odor

unusual bleeding or bruising

upper right abdominal or stomach pain

vomiting of blood

yellow eyes and skin

Incidence not known

Painful or prolonged erection of the penis

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Joint pain

muscle pain

Rare

Bloated

change in taste, or bad, unusual, or unpleasant (after) taste

cold intolerance

excess air or gas in the stomach or intestines

full feeling

general feeling of discomfort or illness

hair loss or thinning of the hair

hives or welts

lack or loss of strength

pain

passing gas

red, sore, or itching skin

sores, welting, or blisters

unusual drowsiness, dullness, or feeling of sluggishness

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.