Warfarin sodium

What is Warfarin sodium?

• Warfarin sodium (Coumadin; Jantoven) is a vitamin K antagonist, used to treat blood clots and to lower the chance of blood clots forming in your body.
• Blood clots can cause a stroke, heart attack, or other serious conditions if they form in the legs or lungs.
• It is not known if warfarin sodium is safe and effective in children.
• It is also used to treat or prevent venous thrombosis (swelling and blood clot in a vein) and pulmonary embolism (a blood clot in the lung).

Warfarin

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What are the uses of this medicine?

Warfarin sodium (Coumadin; Jantoven) is used as:

• Prophylaxis and treatment of venous thrombosis and its extension, pulmonary embolism (PE).
• Prophylaxis and treatment of thromboembolic complications associated with atrial fibrillation (AF) and/or cardiac valve replacement.
• Reduction in the risk of death, recurrent myocardial infarction (MI), and thromboembolic events such as stroke or systemic embolization after myocardial infarction.

Limitations of use:

• Warfarin sodium tablets, USP have no direct effect on an established thrombus, nor does it reverse ischemic tissue damage.

How does this medicine work?

• 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 K1 epoxide.

Who Should Not Use this medicine ?

This medicine cannot be used in patients with:

• Pregnancy, except in women with mechanical heart valves.
• Hemorrhagic tendencies or blood dyscrasias.
• Recent or contemplated surgery of the central nervous system (CNS) or eye, or traumatic surgery resulting in large open surfaces.
• Bleeding tendencies associated with certain conditions.
• Threatened abortion, eclampsia, and preeclampsia.
• Unsupervised patients with potential high levels of non-compliance.
• Spinal puncture and other diagnostic or therapeutic procedures with potential for uncontrollable bleeding.
• Hypersensitivity to warfarin or any component of the product.
• Major regional or lumbar block anesthesia.
• Malignant hypertension.

What drug interactions can this medicine cause?

• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.

Be sure to mention any of the following:

• acyclovir (Zovirax); allopurinol (Zyloprim); alprazolam (Xanax); antibiotics such as ciprofloxacin (Cipro), clarithromycin (Biaxin, in Prevpac), erythromycin (E.E.S., Eryc, Ery-Tab), nafcillin, norfloxacin (Noroxin), sulfinpyrazone, telithromycin (Ketek), and tigecycline (Tygacil); anticoagulants such as argatroban (Acova), dabigatran (Pradaxa), bivalirudin (Angiomax), desirudin (Iprivask), heparin, and lepirudin (Refludan); antifungals such as fluconazole (Diflucan), itraconazole (Onmel, Sporanox), ketoconazole (Nizoral), miconazole (Monistat), posaconazole (Noxafil), terbinafine (Lamisil), voriconazole (Vfend); antiplatelet medications such as cilostazol (Pletal), clopidogrel (Plavix), dipyridamole (Persantine, in Aggrenox), prasugrel (Effient), and ticlopidine (Ticlid); aprepitant (Emend); aspirin or aspirin-containing products and other nonsteroidal anti-inflammatory drugs such as celecoxib (Celebrex), diclofenac (Flector, Voltaren, in Arthrotec), diflunisal, fenoprofen (Nalfon), ibuprofen (Advil, Motrin), indomethacin (Indocin), ketoprofen, ketorolac, mefenamic acid (Ponstel), naproxen (Aleve, Naprosyn), oxaprozin (Daypro), piroxicam (Feldene), and sulindac (Clinoril); bicalutamide; bosentan; certain antiarrhythmic medications such as amiodarone (Cordarone, Nexterone, Pacerone), mexiletine, and propafenone (Rythmol); certain calcium channel blocking medications such as amlodipine (Norvasc, in Azor, Caduet, Exforge, Lotrel, Twynsta), diltiazem (Cardizem, Cartia XT, Dilacor XR, Tiazac) and verapamil (Calan, Isoptin, Verelan, in Tarka); certain medications for asthma such as montelukast (Singulair), zafirlukast (Accolate), and zileuton (Zyflo); certain medications used to treat cancer such as capecitabine (Xeloda), imatinib (Gleevec), and nilotinib (Tasigna); certain medications for cholesterol such as atorvastatin (Lipitor, in Caduet) and fluvastatin (Lescol); certain medications for digestive disorders such as cimetidine (Tagamet), famotidine (Pepcid), and ranitidine (Zantac); certain medications for human immunodeficiency virus (HIV) infection such as amprenavir, atazanavir (Reyataz), efavirenz (Sustiva), etravirine (Intelence), fosamprenavir (Lexiva), indinavir (Crixivan), lopinavir/ritonavir, nelfinavir (Viracept), ritonavir (Norvir), saquinavir (Invirase), and tipranavir (Aptivus); certain medications for narcolepsy such as armodafinil (Nuvigil) and modafinil (Provigil); certain medications for seizures such as carbamazepine (Carbatrol, Equetro, Tegretol), phenobarbital, phenytoin (Dilantin, Phenytek), and rufinamide (Banzel); certain medications to treat tuberculosis such as isoniazid (in Rifamate, Rifater) and rifampin (Rifadin, in Rifamate, Rifater); certain selective serotonin reuptake inhibitors (SSRIs) or selective serotonin and norepinephrine reuptake inhibitors (SNRIs) such as citalopram (Celexa), desvenlafaxine (Pristiq), duloxetine (Cymbalta), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem, in Symbyax), fluvoxamine (Luvox), milnacipran (Savella), paroxetine (Paxil, Pexeva), sertraline (Zoloft), venlafaxine (Effexor) corticosteroids such as prednisone; cyclosporine (Neoral, Sandimmune); disulfiram (Antabuse); methoxsalen (Oxsoralen, Uvadex); metronidazole (Flagyl); nefazodone (Serzone), oral contraceptives (birth control pills); oxandrolone (Oxandrin); pioglitazone (Actos, in Actoplus Met, Duetact, Oseni); propranolol (Inderal) or vilazodone (Viibryd).

Is this medicine FDA approved?

• Warfarin was approved for use in the United States in 1961 and remains in wide use with more than 30 million prescriptions filled yearly.

How should this medicine be used?

Recommended dosage:

• The dosage and administration of warfarin sodium must be individualized for each patient according to the patient’s INR response to the drug.
• The typical dose is 5 mg daily for 2 to 4 days followed by 2 to 10 mg daily, based upon measurements of prothrombin time aiming at an international normalized ratio (INR) value of 2 to 3.

Administration:

• Warfarin comes as a tablet to take by mouth.
• It is usually taken once a day with or without food.
• Yake warfarin at around the same time every day.
• Take warfarin sodium exactly as prescribed.
• Your healthcare provider will adjust your dose from time to time depending on your response to warfarin sodium.
• You must have regular blood tests and visits with your healthcare provider to monitor your condition.
• If you miss a dose of warfarin sodium, call your healthcare provider.
• Take the dose as soon as possible on the same day.
• Do not take a double dose of warfarin sodium the next day to make up for a missed dose.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As Scored tablets: 1, 2, 2.5, 3, 4, 5, 6, 7.5, or 10 mg

This medicine is available in fallowing brand namesː

• Coumadin; Jantoven

What side effects can this medication cause?

The most common side effects of this medicine may include:

• Side effects not directly attributable to the anticoagulant activity of warfarin are not common, but can include nausea, abdominal discomfort, diarrhea, anorexia, fever, alopecia, skin necrosis and bluish discoloration.

Less common, but serious side effects may include:

• bleeding which can be serious and sometimes lead to death
• skin necrosis or gangrene
• Purple toes syndrome

What special precautions should I follow?

• Warfarin sodium can cause major or fatal bleeding. Bleeding is more likely to occur within the first month. Instruct patients about prevention measures to minimize risk of bleeding and to report signs and symptoms of bleeding.
• Necrosis and/or gangrene of skin and other tissues is an uncommon but serious risk. Discontinue warfarin sodium and consider alternative anticoagulants if necessary.
• Anticoagulation therapy with warfarin sodium may enhance the release of atheromatous plaque emboli. Some cases have progressed to necrosis or death. Discontinue warfarin sodium if such emboli occur.
• Do not use warfarin sodium as initial therapy in patients with heparin-induced thrombocytopenia (HIT) and with heparin-induced thrombocytopenia with thrombosis syndrome (HITTS). Initial therapy with warfarin sodium in HIT has resulted in cases of amputation and death. Warfarin sodium may be considered after platelet count has normalized.
• Warfarin sodium can cause fetal harm when administered to a pregnant woman. Warfarin sodium exposure during pregnancy can cause pregnancy loss, birth defects, or fetal death. Discuss pregnancy planning with females of reproductive potential who are on warfarin sodium therapy.
• Do not do any activity or sport that may cause a serious injury.
• Do not take or discontinue any other drug, including salicylates (e.g., aspirin and topical analgesics), other over-the-counter drugs, and botanical (herbal) products except on advice of your physician.
• Notify their physician immediately if any unusual bleeding or symptoms occur. Signs and symptoms of bleeding include: pain, swelling or discomfort, prolonged bleeding from cuts, increased menstrual flow or vaginal bleeding, nosebleeds, bleeding of gums from brushing, unusual bleeding or bruising, red or dark brown urine, red or tar black stools, headache, dizziness, or weakness.
• If the prescribed dose of warfarin is missed, take the dose as soon as possible on the same day but do not take a double dose of warfarin the next day to make up for missed doses.
• Eat a normal, balanced diet to maintain a consistent intake of vitamin K. Avoid drastic changes in dietary habits, such as eating large amounts of leafy, green vegetables.
• Contact their physician to report any serious illness, such as severe diarrhea, infection or fever.
• Be aware that if therapy with warfarin is discontinued, the anticoagulant effects of warfarin may persist for about 2 to 5 days.
• Caution should be exercised when warfarin sodium is administered to a nursing woman.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• hemorrhagic complications

Management of overdosage:

• In case of overdose, call the poison control helpline of your country. In the United States, call 1-800-222-1222.

• Overdose related information is also available online at poisonhelp.org/help.
• In the event that the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services. In the United States, call 911.
• Injected enoxaparin sodium injection may be largely neutralized by the slow intravenous injection of protamine sulfate (1% solution). The dose of protamine sulfate should be equal to the dose of enoxaparin sodium injected: 1 mg protamine sulfate should be administered to neutralize 1 mg enoxaparin sodium injection, if enoxaparin sodium injection was administered in the previous 8 hours.
• An infusion of 0.5 mg protamine per 1 mg of enoxaparin sodium may be administered if enoxaparin sodium was administered greater than 8 hours previous to the protamine administration.
• Particular care should be taken to avoid overdosage with protamine sulfate.
• Administration of protamine sulfate can cause severe hypotensive and anaphylactoid reactions.
• Because fatal reactions, often resembling anaphylaxis, have been reported with protamine sulfate, it should be given only when resuscitation techniques and treatment of anaphylactic shock are readily available.

Can this medicine be used in pregnancy?

• Pregnancy Category D for women with mechanical heart valves.
• Pregnancy Category X for other pregnant populations.
• Warfarin sodium tablets are contraindicated in women who are pregnant except in pregnant women with mechanical heart valves, who are at high risk of thromboembolism, and for whom the benefits of warfarin sodium may outweigh the risks. Warfarin sodium can cause fetal harm when administered to a pregnant woman.

Can this medicine be used in children?

• Adequate and well-controlled studies with warfarin sodium have not been conducted in any pediatric population, and the optimum dosing, safety, and efficacy in pediatric patients is unknown. Pediatric use of warfarin sodium is based on adult data and recommendations.
• Pediatric patients administered warfarin sodium should avoid any activity or sport that may result in traumatic injury.
• Infants and children receiving vitamin K-supplemented nutrition, including infant formulas, may be resistant to warfarin therapy, while human milk-fed infants may be sensitive to warfarin therapy.

What are the active and inactive ingredients in this medicine?

• Active ingredient: Warfarin Sodium, USP

• Inactive ingredients: Each warfarin sodium tablet intended for oral administration contains warfarin sodium clathrates equivalent to 1 mg or 2 mg or 2.5 mg or 3 mg or 4 mg or 5 mg or 6 mg or 7.5 mg or 10 mg of warfarin sodium.

• In addition each tablet contains the inactive ingredients lactose monohydrate, starch, pregelatinised starch, hydroxypropyl cellulose, starlac and magnesium stearate.

Who manufactures and distributes this medicine?

Manufactured for:

• Camber Pharmaceuticals Inc.
• Piscataway. NJ

Manufactured By:

• InvaGen Pharmaceuticals, Inc.
• Hauppauge, NY

What should I know about storage and disposal of this medication?

• Store warfarin sodium at 20°C to 25°C (68°F to 77°F).
• Keep warfarin sodium in a tightly closed container, and keep warfarin out of the light.

• Dailymed label info on Warfarin sodium
• FDA Warfarin sodium

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