Drug Info: A: Anticoagulants (Systemic)

Some commonly used brand names are:

In the U.S.—

In Canada—

Other commonly used names are nicoumalone; dicoumarol.

• Anticoagulant --Acenocoumarol; Anisindione; Dicumarol; Warfarin

Anticoagulants decrease the clotting ability of the bloodand therefore help to prevent harmful clots from forming inthe blood vessels. These medicines are sometimes called bloodthinners, although they do not actually thin the blood. Theyalso will not dissolve clots that already have formed, butthey may prevent the clots from becoming larger and causingmore serious problems. They are often used as treatment forcertain blood vessel, heart, and lung conditions.

In order for an anticoagulant to help you without causingserious bleeding, it must be used properly and all of theprecautions concerning its use must be followed exactly. Besure that you have discussed the use of this medicine withyour doctor. It is very important that you understand all ofyour doctor's orders and that you are willing and able tofollow them exactly.

Anticoagulants are available only with your doctor'sprescription, in the following dosage forms:

• Oral
• Acenocoumarol
  • Tablets (Canada)
• Anisindione
  • Tablets (U.S.)
• Dicumarol
  • Tablets (U.S.)
• Warfarin
  • Tablets (U.S. and Canada)

• Parenteral
• Warfarin
  • Injection (U.S. and Canada)

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

Allergies—Tell your doctor if you haveever had any unusual or allergic reaction to ananticoagulant. Also tell your health care professional if youare allergic to any other substances, such as foods,preservatives, or dyes.

Pregnancy—Anticoagulants may causebirth defects. They may also cause other problems affectingthe physical or mental growth of the fetus or newborn baby.In addition, use of this medicine during the last 6 months ofpregnancy may increase the chance of severe, possibly fatal,bleeding in the fetus. If taken during the last few weeks ofpregnancy, anticoagulants may cause severe bleeding in boththe fetus and the mother before or during delivery and in thenewborn infant.

Do not begin taking this medicine during pregnancy, anddo not become pregnant while taking it, unless you havefirst discussed the possible effects of this medicine withyour doctor. Also, if you suspect that you may be pregnantand you are already taking an anticoagulant, check with yourdoctor at once. Your doctor may suggest that you take adifferent anticoagulant that is less likely to harm the fetusor the newborn infant during all or part of your pregnancy.Anticoagulants may also cause severe bleeding in the motherif taken soon after the baby is born.

Breast-feeding—Warfarin is not likelyto cause problems in nursing babies. Other anticoagulants maypass into the breast milk. A blood test can be done to see ifunwanted effects are occurring in the nursing baby. Ifnecessary, another medicine that will overcome any unwantedeffects of the anticoagulant can be given to the baby.

Children—Very young babies may beespecially sensitive to the effects of anticoagulants. Thismay increase the chance of bleeding during treatment.

Older adults—Elderly people areespecially sensitive to the effects of anticoagulants. Thismay increase the chance of bleeding during treatment.

Other medicines—Although certainmedicines should not be used together at all, in other casestwo different medicines may be used together even if aninteraction might occur. In these cases, your doctor may wantto change the dose, or other precautions may be necessary. Many different medicines can affect the wayanticoagulants work in your body . Therefore, it is veryimportant that your health care professional knows if you aretaking any other prescription or nonprescription(over-the-counter [OTC]) medicine, especially:

• Amiodarone (e.g., Cordarone) or
• Cimetidine (e.g., Tagamet) or
• Metronidazole (e.g., Flagyl) or
• Omeprazole (e.g., Prilosec) or
• Zafirlukast (e.g., Accolate)—Effects ofanticoagulants may be increased because of slower removalfrom the body

• Anabolic steroids (nandrolone [e.g., Anabolin],oxandrolone [e.g., Anavar], oxymetholone [e.g., Anadrol],stanozolol [e.g., Winstrol]) or
• Androgens (male hormones) or
• Antifungals, azole (e.g., Diflucan) or
• Antithyroid agents (medicine for overactive thyroid)or
• Aspirin or other salicylates, including bismuthsubsalicylate (e.g., Pepto-Bismol) or
• Cephalosporins (medicine for infection) or
• Cinchophen or
• Clofibrate (e.g., Abitrate, Atromid-S) or
• Danazol (e.g., Danocrine) or
• Dextrothyroxine or
• Diflunisal or
• Disulfiram (e.g., Antabuse) or
• Fluvoxamine (e.g., Luvox) or
• Inflammation or pain medicine (except narcotics)or
• Lepirudin (e.g., Refludan) or
• Medications causing low platelet count or
• Paroxetine (e.g., Paxil) or
• Propafenone (e.g., Rythmol) or
• Quinidine (e.g., Quinidex) or
• Sertraline (e.g., Zoloft) or
• Sulfapyridine or
• Sulfasalazine (e.g., Azulfidine) or
• Thyroid hormones or
• Ticlopidine (e.g., Ticlid) or
• Zileuton (e.g., Zyflo)—These medications mayincrease the effects of anticoagulants and may increase thechance of bleeding

• Carbenicillin by injection (e.g., Geopen) or
• Dipyridamole (e.g., Persantine) or
• Divalproex (e.g., Depakote) or
• Moxalactam (e.g., Moxam) or
• Pentoxifylline (e.g., Trantal) or
• Plicamycin (e.g., Mithracin) or
• Sulfinpyrazone (e.g., Anturane) or
• Thrombolytic agents (medicine for blood clots) or
• Ticarcillin (e.g., Ticar) or
• Valproic acid (e.g., Depakene)—Using any of thesemedicines together with anticoagulants may increase thechance of bleeding

• Alcohol (with chronic use) or
• Barbiturates or
• Carbamazepine (e.g., Tegretol) or
• Corticosteroids (cortisone-like medicine) or
• Glutethimide (e.g., Doriden) or
• Griseofulvin (e.g., Fulvicin) or
• Phenylbutazone (e.g., Butazolidin) or
• Phenytoin (e.g., Dilantin) or
• Primidone (e.g., Mysoline) or
• Rifampin (e.g., Rifadin)—Effects ofanticoagulants may be decreased because of faster removalfrom the body

• Vitamin K (e.g., AquaMEPHYTON)—Vitamin K helpsproduce some important blood clotting factors and maydecrease the effects of anticoagulants if used at the sametime

• Aneurysm (swelling in a blood vessel) especially in thehead or chest or
• Bleeding in the brain or
• Blood disorders or diseases, especially thrombocytopenia(low platelet count), polycythemia (high red blood cellcount), or leukemia or
• Bruising, excessive or
• Cancer of the internal organs, especially of the abdomenor
• Childbirth, recent or
• Diabetes mellitus (sugar diabetes) or
• Diverticulitis or
• Falls or blows to the body or head or
• Heart infection or
• Hemophilia or other bleeding problems or
• Hypertension (high blood pressure) or
• Inflammation of blood vessels or
• Intestinal problems, especially conditions that mayaffect the absorption of food or vitamins or
• Liver disease or
• Pregnancy, terminated or
• Spinal anesthetics or spinal puncture or
• Surgery, major, especially of the head or eye, or dentalsurgery or
• Toxemia of pregnancy or
• Ulcers, active, of the stomach, lung, or urinary tractor
• Vitamin K deficiency or
• Wounds, open, surgical or from an ulcer—Theseconditions may increase the chance of bleeding

In addition, it is important that you tell your doctor ifyou are now being treated by any other medical doctor ordentist.

Take this medicine only as directed by your doctor.Do not take more or less of it, do not take it more often,and do not take it for a longer time than your doctorordered. This is especially important for elderly patients,who are especially sensitive to the effects ofanticoagulants. Also, it is best if you take this medicine atthe same time each day.

Your doctor or health care professional should check yourprogress at regular visits. A blood test must be takenregularly to see how fast your blood is clotting. This willhelp your doctor decide on the proper amount of anticoagulantyou should be taking each day. Some patients may be able totest their blood at home; discuss with your doctor whether ornot this is possible for you.

Dosing—

The dose of these medicines will be different fordifferent patients. Follow your doctor's orders or the directions on thelabel. The following information includes only theaverage doses of these medicines. If your dose is different, do not change it unlessyour doctor tells you to do so.

• For acenocoumarol
• For oral dosage form (tablets):
  • For preventing or treating harmful blood clots:
    • Adults—The usual dose is 1 to 10 milligrams(mg) per day, adjusted according to blood tests.
    • Children—Dose must be determined by yourdoctor.

• For anisindione
• For oral dosage form (tablets):
  • For preventing or treating harmful blood clots:
    • Adults—The usual dose is 25 to 250 milligrams(mg) per day, adjusted according to blood tests.
    • Children—Dose must be determined by yourdoctor.

• For dicumarol
• For oral dosage form (tablets):
  • For preventing or treating harmful blood clots:
    • Adults—The usual dose is 25 to 200 milligrams(mg) per day, adjusted according to blood tests.
    • Children—Dose must be determined by yourdoctor.

• For warfarin
• For oral dosage form (tablets):
  • For preventing or treating harmful blood clots:
    • Adults—The starting dose is usually 2 to 5milligrams (mg) per day for two to four days. Then,your dose may be adjusted, depending on your conditionand results of routine blood tests.
    • Children—Dose must be determined by yourdoctor.
• For injection dosage form:
  • For preventing or treating harmful blood clots:
    • Adults—The starting dose is usually 2 to 5milligrams (mg) per day for two to four days. Then,your dose may be adjusted, depending on your conditionand results of routine blood tests.
    • Children—Dose must be determined by yourdoctor.

Missed dose—

If you miss a dose of this medicine, take it as soon aspossible. Then go back to your regular dosing schedule. Ifyou do not remember until the next day, do not take themissed dose at all and do not double the next one. Doubling the dose may cause bleeding. Instead, goback to your regular dosing schedule. It is recommended thatyou keep a record of each dose as you take it to avoidmistakes. Also, be sure to give your doctor a record of anydoses you miss. If you have any questions about this, checkwith your doctor.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store this medicine in the bathroom, near thekitchen sink, or in other damp places. Heat or moisture maycause the medicine to break down.
• Do not keep outdated medicine or medicine no longerneeded. Be sure that any discarded medicine is out of thereach of children.

Tell all medical doctors, dentists, and pharmacists yougo to that you are taking this medicine.

Check with your doctor right away if you notice anyunusual bleeding or bruising.

Check with your health care professional before you startor stop taking any other medicine, or change the amount youare taking . This includes any nonprescription(over-the-counter [OTC]) medicine, even aspirin oracetaminophen. Many medicines change the way this medicineaffects your body. You may not be able to take the othermedicine, or the dose of your anticoagulant may need to bechanged.

It is important that you carry identification statingthat you are using this medicine. If you have anyquestions about what kind of identification to carry, checkwith your health care professional.

While you are taking this medicine, it is very importantthat you avoid sports and activities that may cause you to beinjured. Report to your doctor any falls, blows to the bodyor head, or other injuries, since serious internal bleedingmay occur without your knowing about it.

Be careful to avoid cutting yourself. This includes takingspecial care in brushing your teeth and in shaving. Use asoft toothbrush and floss gently. Also, it is best to use anelectric shaver rather than a blade.

Drinking too much alcohol may change the way thisanticoagulant affects your body. You should not drinkregularly on a daily basis or take more than 1 or 2 drinks atany time. If you have any questions about this, check withyour doctor.

The foods that you eat may also affect the way thismedicine affects your body. Eat a normal, balanced diet whileyou are taking this medicine. Do not go on a reducing diet, make other changes in youreating habits, start taking vitamins, or begin using othernutrition supplements unless you have first checked with yourhealth care professional. Also, check with your doctorif you are unable to eat for several days or if you havecontinuing stomach upset, diarrhea, or fever. Theseprecautions are important because the effects of theanticoagulant depend on the amount of vitamin K in your body.Therefore, it is best to have the same amount of vitamin K inyour body every day. Some multiple vitamins and somenutrition supplements contain vitamin K. Vitamin K is alsopresent in green, leafy vegetables (such as broccoli,cabbage, collard greens, kale, lettuce, and spinach) and somevegetable oils. It is especially important that you do notmake large changes in the amounts of these foods that you eatevery day while you are taking an anticoagulant.

Check with your doctor if you are unable to eat forseveral days or if you have continuing stomach upset,diarrhea, or fever. This could decrease the amount of vitaminK that gets into your body and could affect thismedicine.

Be careful if the weather is very hot for several days.This could increase the effects of the medicine.

After you stop taking this medicine, your body will needtime to recover before your blood clotting ability returns tonormal. Your health care professional can tell you how longthis will take depending on which anticoagulant you weretaking. Use the same caution during this period of time as youdid while you were taking the anticoagulant.

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

Since many things can affect the way your body reacts tothis medicine, you should always watch for signs of unusualbleeding. Unusual bleeding may mean that your body is gettingmore medicine than it needs. Check with your doctor immediately if any of the followingsigns of bleeding or overdose occur:

• Bleeding from gums when brushing teeth; blood in urine;nosebleeds; pinpoint red spots on skin; unusual bleeding orbruising ; unusually heavy bleeding or oozing from cuts orwounds; unusually heavy or unexpected menstrualbleeding

• Signs and symptoms of bleeding inside thebody—dose-related
  • Abdominal or stomach pain or swelling; back pain orbackaches; black, tarry stools; bleeding in eye; bloodin stools; blood in vomit or vomit that looks likecoffee grounds; blood in urine; blurred vision; chestpain; confusion; constipation; coughing up blood;diarrhea (sudden and severe); dizziness or fainting;headache (continuing or severe); joint pain, stiffness,or swelling; loss of appetite; nausea and vomiting(severe); nervousness; numbness or tingling of hands,feet, or face; paralysis; shortness of breath; weakness(sudden)
  
  

Also, check with your doctor as soon as possible if any ofthe following side effects occur:

• Less common
  • Cough or hoarseness; fever or chills ; lower backor side pain; painful or difficult urination; skinrash, hives, or itching
  
  

• Rare
  • Blisters or itching on skin; blue or purple toes;dark urine; pain in toes; painful red sores on skin,especially on thighs, breasts, penis, or buttocks;sores, ulcers, or white spots in mouth or throat;sudden increase or decrease in amount of urine;swelling of face, feet, and/or lower legs; trouble inbreathing; yellow eyes or skin
  
  

Other side effects may occur that usually do not needmedical attention. These side effects may go away duringtreatment as your body adjusts to the medicine. However,check with your doctor if any of the following side effectscontinue or are bothersome:

• Less common or rare
  • Bloated stomach or gas (with dicumarol); coldintolerance; diarrhea (more common with dicumarol) ;loss of appetite; nausea or vomiting (more common withdicumarol); stomach cramps or pain
  
  

These medicines sometimes cause temporary loss of hair onthe scalp.

Depending on your diet, anisindione may cause your urine to turn orange. Sinceit may be hard to tell the difference between blood in theurine and this normal color change, check with your doctor ifyou notice any color change in your urine.

Other side effects not listed above may also occur in somepatients. If you notice any other effects, check with yourdoctor.