Warfarin is useful for preventing or overcoming blood clots that can cause blockages in blood vessels. This medicine should be consumed routinely and under the supervision of a doctor.

Warfarin works by inhibiting the work of vitamin K, which is one of the important factors in the blood clotting process. This drug is used in the treatment of pulmonary embolism , mild stroke ( transient ischemic attack / TIA ), or blockage of venous blood vessels due to blood clots (venous thrombosis).

Warfarin is also used to prevent blood vessel blockage and embolism in people who are at high risk of experiencing it, such as patients with rheumatic heart disease , people with artificial heart valves, or people with atrial fibrillation .

Warfarin brand names : Simarc 2, Notisil 5, Notisil 2, Warfarin, Warfarin Sodium Clathrate

What Is Warfarin? 

Group Prescription drugs
Category Anticoagulants
Benefits Prevents and overcomes blood clotting
Consumed by Adults
Warfarin for pregnant and lactating women Category X: Studies on experimental animals and humans have shown abnormalities in the fetus or risks to the fetus. Medicines in this category should not be used by women who are or have the possibility of becoming pregnant.

Category D for pregnant women with artificial heart valves: There is evidence that the content of the drug poses a risk to the human fetus, but the magnitude of the benefit obtained may be greater than the risk, for example to overcome a life-threatening situation.

Warfarin can be slightly absorbed into breast milk. Consult the use of warfarin with a doctor if you are breastfeeding.

Drug form Tablets

Warnings Before Consuming Warfarin

Consider the following before taking warfarin:

  • Do not take warfarin if you are allergic to this medicine.
  • Tell your doctor if you have had or are currently suffering from vascular disorders such as aneurysms , alcohol addiction, mental or mood disorders, memory disorders, liver disease, or kidney disease.
  • Tell your doctor if you have had or are currently suffering from blood disorders such as anemia or hemophilia , or bleeding disorders, such as gastrointestinal or brain bleeding .
  • Tell the doctor if you have recently undergone surgery, have recently suffered a serious injury, often fall, or are often injured.
  • Tell your doctor if you are or will be taking any other drugs, supplements, or herbal products, to anticipate drug interactions.
  • Tell your doctor if during treatment with warfarin you lose your appetite or have fever, vomiting, or diarrhea for >2 days. If you are going to be given antibiotics by another doctor, tell that doctor that you are taking warfarin.
  • Do not consume alcoholic beverages while undergoing treatment with warfarin, as it can increase your risk of stomach bleeding.
  • Tell your doctor or medical staff that you are taking warfarin if you plan to get an injection into a muscle, for example for a vaccine. Make sure the injection into the muscle is given to the arm so that the possibility of bleeding can be better anticipated.
  • Avoid activities such as sports with hard physical contact. Be careful when doing activities with sharp objects or that risk causing bleeding, such as clipping nails, shaving or brushing teeth.
  • Tell your doctor that you are taking warfarin if you are scheduled to undergo surgery, including dental surgery.
  • Use a condom or other contraceptive device to prevent pregnancy, from the time you start taking warfarin until 1 month after using the drug, because this drug can increase the risk of birth defects.
  • Immediately see a doctor if an allergic reaction to the drug or a serious side effect occurs, after using warfarin.

Dosage and Administration of Warfarin

The initial dose of warfarin is 5–10 mg per day, for the first 1–2 days. Treatment dose 3–9 mg per day, depending on the blood test results during routine evaluation.

How to Consume Warfarin Correctly

Be sure to follow your doctor 's recommendations and read the instructions on the medicine package before taking warfarin.

Do not increase the dose or stop the consumption of this medicine without first consulting a doctor. Warfarin can be consumed before or after meals.

Consume warfarin regularly at the same time every day to get the maximum effect. If you forget to consume it, immediately consume this medicine as soon as you remember if it is still on the same day. If it is the next day, ignore the dose and do not double the dose of the next medicine.

Store warfarin in a closed container in a cool, dry place. Keep this medicine out of direct sunlight and out of the reach of children.

Warfarin Interactions with Other Drugs

The following are interactions that can occur if warfarin is used with certain drugs:

  • Increased risk of potentially fatal bleeding if used with fibrinolytic drugs, such as alteplase or streptokinase
  • Increased risk of bleeding if used with other anticoagulants , such as argatroban, dabigatran, or heparin; antiplatelets , such as aspirin, cilostazol, or clopidogrel; NSAIDs , such as celecoxib, diclofenac, or ibuprofen; or SSRI antidepressants , such as citalopram or paroxetine
  • Increased risk of gall bladder and liver disorders if used with ticlopidine
  • Increased risk of bleeding if used with amiodarone , capecitabine, cotrimoxazole , acyclovir, ciprofloxacin , alprazolam, or atorvastatin
  • Decreased effectiveness of warfarin if used with carbamazepine , rifampicin, phenytoin , efavirenz, or sofosbuvir
  • Decreased or increased effectiveness of warfarin if used with prednisone

In addition to medicines, certain foods or drinks can also interact with warfarin. Avoid consuming cranberry or pomegranate juice during treatment with warfarin, as it can increase the risk of bleeding.

In addition, foods and drinks with high vitamin K content , such as liver, green leafy vegetables, and green tea can reduce the effectiveness of warfarin. Reduce the intake of the above foods while you are taking warfarin. Consult a nutritionist if necessary.

Side Effects and Dangers of Warfarin

Side effects that may arise after consuming warfarin include:

  • Nausea
  • Loss of appetite
  • Stomach or abdominal pain
  • Mild skin rash
  • Hair loss
  • Bleeding gums after brushing
  • The body bruises easily , and bruises take longer to fade
  • Nosebleeds (infrequent and lasting <10 minutes)
  • Bleeding from a cut takes a little longer to stop
  • Menstrual bleeding is more or the duration of the period is longer than usual

Check with your doctor if the above side effects continue or worsen. You should also seek medical help if you develop an allergic reaction to the drug or develop serious side effects, such as:

  • Runny nose for more than 10 minutes
  • Blood from the wound continued to flow
  • Enlarging bruises
  • Vomit blood
  • Red pee or black stools
  • Bleeding in the head, which can be marked by a very severe headache, seizures , sudden visual disturbances, or weakness and numbness on one side of the body
Back to blog