Health Guide
Drug Guide

Anticoagulant (Oral route, parenteral route)

Brand Names:

Dosage Forms:

Uses of This Medicine:

Anticoagulants decrease the clotting ability of the blood and therefore help to prevent harmful clots from forming in the blood vessels. These medicines are sometimes called blood thinners, although they do not actually thin the blood. They also will not dissolve clots that already have formed, but they may prevent the clots from becoming larger and causing more serious problems. They are often used as treatment for certain blood vessel, heart, and lung conditions.

In order for an anticoagulant to help you without causing serious bleeding, it must be used properly and all of the precautions concerning its use must be followed exactly. Be sure that you have discussed the use of this medicine with your doctor. It is very important that you understand all of your doctor's orders and that you are willing and able to follow them exactly.

Anticoagulants are available only with your doctor's prescription.

Before Using This Medicine:


Tell your doctor if you have ever had any unusual or allergic reaction to medicines in this group 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.


Very young babies may be especially sensitive to the effects of anticoagulants. This may increase the chance of bleeding during treatment.

Older adults

Elderly people are especially sensitive to the effects of anticoagulants. This may increase the chance of bleeding during treatment.


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

Do not begin taking this medicine during pregnancy, and do not become pregnant while taking it, unless you have first discussed the possible effects of this medicine with your doctor. Also, if you suspect that you may be pregnant and you are already taking an anticoagulant, check with your doctor at once. Your doctor may suggest that you take a different anticoagulant that is less likely to harm the fetus or the newborn infant during all or part of your pregnancy. Anticoagulants may also cause severe bleeding in the mother if taken soon after the baby is born.


Warfarin is not likely to cause problems in nursing babies. Other anticoagulants may pass into the breast milk. A blood test can be done to see if unwanted effects are occurring in the nursing baby. If necessary, another medicine that will overcome any unwanted effects of the anticoagulant can be given to the baby.

Other medicines

Using medicines in this class 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.

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.

Other medical problems

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

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

Proper Use of This Medicine:

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 doctor ordered. This is especially important for elderly patients, who are especially sensitive to the effects of anticoagulants. Also, it is best if you take this medicine at the same time each day.

Your doctor or health care professional should check your progress at regular visits. A blood test must be taken regularly to see how fast your blood is clotting. This will help your doctor decide on the proper amount of anticoagulant you should be taking each day. Some patients may be able to test their blood at home; discuss with your doctor whether or not this is possible for you.


The dose medicines in this class will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you do not remember the missed dose until the next day, do not take the missed dose at all and do not double the next one. Doubling the dose may cause bleeding. Instead, go back to your regular dosing schedule. It is recommended that you keep a record of each dose as you take it to avoid mistakes. Also, be sure to give your doctor a record of any doses you miss. If you have any questions about this, check with your doctor.


Keep out of the reach of children.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Do not keep outdated medicine or medicine no longer needed.

Precautions While Using This Medicine:

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

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

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

It is important that you carry identification stating that you are using this medicine. If you have any questions about what kind of identification to carry, check with your health care professional.

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

Be careful to avoid cutting yourself. This includes taking special care in brushing your teeth and in shaving. Use a soft toothbrush and floss gently. Also, it is best to use an electric shaver rather than a blade.

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

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

Check with your doctor if you are unable to eat for several days or if you have continuing stomach upset, diarrhea, or fever. This could decrease the amount of vitamin K that gets into your body and could affect this medicine.

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 need time to recover before your blood clotting ability returns to normal. Your health care professional can tell you how long this will take depending on which anticoagulant you were taking. Use the same caution during this period of time as you did while you were taking the anticoagulant.

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.

Since many things can affect the way your body reacts to this medicine, you should always watch for signs of unusual bleeding. Unusual bleeding may mean that your body is getting more medicine than it needs. Check with your doctor immediately if any of the following signs of bleeding or overdose occur:

Bleeding from gums when brushing teeth
blood in urine
pinpoint red spots on skin
unusual bleeding or bruising
unusually heavy bleeding or oozing from cuts or wounds
unusually heavy or unexpected menstrual bleeding
Signs and symptoms of bleeding inside the body dose-related
Abdominal or stomach pain or swelling
back pain or backaches
black, tarry stools
bleeding in eye
blood in stools
blood in vomit or vomit that looks like coffee grounds
blood in urine
blurred vision
chest pain
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)
numbness or tingling of hands, feet, or face
shortness of breath
weakness (sudden)

Check with your doctor as soon as possible if any of the following side effects occur:

Less common
Cough or hoarseness
fever or chills
lower back or side pain
painful or difficult urination
skin rash, hives, or itching
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 in breathing
yellow eyes or skin

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 or rare
Bloated stomach or gas (with dicumarol)
cold intolerance
diarrhea (more common with dicumarol)
loss of appetite
nausea or vomiting (more common with dicumarol)
stomach cramps or pain

These medicines sometimes cause temporary loss of hair on the scalp.

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

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

Last Updated: 6/12/2013

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