How to make safe use of anticoagulants

If you must take an anticoagulant, you may have some concerns about its use. The medications belonging to this class of drugs are safe and beneficial when a few important precautions are taken.


When the body is injured, certain mechanisms enable it to minimize the damages. This process is called coagulation; a mechanism that enables the blood to form a plug (or clot) at the injury site, stopping the bleeding.

Although this mechanism is beneficial when injury occurs, it can unfortunately cause inconveniences. Blood clots can also form in situations other than from an injury and cause significant complications, such as the ones listed below:

  • cerebrovascular accident (CVA or stroke)
  • myocardial infarction (heart attack)
  • pulmonary embolism (blood clot in the lung's blood vessels)
  • deep vein thrombosis

Various risk factors, such as cardiac arrhythmia (atrial fibrillation), the presence of a heart valve or some surgical procedures can predispose a person to these complications and require the use of an anticoagulant. This type of medication helps to prevent the formation of clots by blocking the action of certain clotting factors.

Types of anticoagulants

There are two main types of anticoagulants—injectable and oral (taken by mouth) anticoagulants. Injectable anticoagulants include unfractionated heparin and low molecular weight heparins. These products are often reserved for specific situations, including during pregnancy or in the perioperative period (immediately before or after surgery).

Oral anticoagulants are primarily used in general. The most widely known oral anticoagulant is warfarin, commercialized under the name Coumadin®. Among other oral anticoagulants are pixaban (Eliquis®), dabigatran (Pradaxa®) and rivaroxaban (Xarelto®). The choice of an anticoagulant depends on several factors, including:

  • the medical issue requiring its use
  • your age
  • the condition of your kidneys
  • the other medications you take

The risk of bleeding

Because anticoagulants act by blocking the clotting process, their main side effect is to increase the risk of bleeding. Although bleeding is generally light, transient, and without serious consequence, it is important to mention to any healthcare professional (your dentist, for instance) that you are taking an anticoagulant. Wearing a medical bracelet is also recommended.

The use of anticoagulants can, in some cases, be at the root of major bleeding complications. However, this risk is minimized when dosage and medical recommendations are followed. Major bleeding can often be explained by dosage errors, medication misuse, interactions with other medications or health issues specific to that person.

Bleeding can occur in several areas of the body and manifest itself in various ways, including via the signs and symptoms listed below:

  • presence of blood in the urine (pinkish or reddish coloured urine)
  • dark stool or stool mixed with blood
  • Brown coloured vomit (resembling coffee beans) or mixed with blood
  • unusual bruises (i.e. that appear without reason)
  • red coughed up sputum
  • persistent nose bleeds
  • intense pain to the head or abdomen, and
  • a cut that bleeds continuously

In the case of unusual bleeding, you should consult a healthcare professional. Note that an injury to the head (following a knock to the head or a fall) should always be evaluated by a doctor as soon as possible. If in doubt, your pharmacist can help you determine if an emergency medical visit is necessary or if you can wait a few days before seeing your doctor. Don't hesitate to speak to your pharmacist about it.

The particularities of warfarin

Rivaroxaban, dabigatran, and apixaban share the common characteristic of producing a predictable clotting effect for a given dose. This means that it is not necessary to do tests or blood tests to measure the drug's clotting effect.

However, this is not the case for warfarin. In fact, a blood test is necessary to check for a clotting effect, as an effective dose of warfarin varies from one person to another. The International Normalized Ratio (INR) can be measured from the drawn blood to determine if the warfarin dose is too high (risk of bleeding) or too low (risk of a clot). Therefore, if you take warfarin, it is crucial that you diligently attend your appointments to have the prescribed blood tests done.

Warning! This does not mean that medical follow-up is less important if you take an anticoagulant other than warfarin—your doctor must still periodically assess your health condition to ensure that the medication is still suitable for you.

Anticoagulants and interactions

Several prescription or over-the-counter medications can interact with your anticoagulant. Your pharmacist has the role of determining the possible interactions with prescribed products and of managing them. However, it is your responsibility to check with your pharmacist or doctor before taking over-the-counter products, as many of them can interact with anticoagulants:

  • acetaminophen can increase the clotting effect of warfarin, depending on the dose
  • anti-inflammatory drugs (such as ibuprofen) can increase the risk of bleeding if they are taken at the same time as an anticoagulant, and
  • several natural products can also hinder the clotting process and increase the risk of bleeding when taken with an anticoagulant

In regards to warfarin, it is important to know that the vitamin K contained in foods affects how the medication functions. An increased intake of vitamin K can lower warfarin's effectiveness. This does not mean that you should not eat food containing vitamin K, but instead, that you should maintain a constant source of it to avoid INR from varying. Vitamin K is mostly found in leafy green vegetables such as kale, broccoli, spinach, Brussels sprouts, etc.

Some advice

Here is some additional information about the safe use of an anticoagulant:

  • Avoid activities that expose you to potential blows or knocks, such as contact sports.
  • Pay particular attention when manipulating sharp objects (i.e. scissors, knives, blades, etc.).
  • Choose an electric razor rather than a manual razor blade.
  • Wear protective gloves during outdoor activities, such as gardening.
  • Use a tooth brush with gentle bristles to avoid bleeding gums.
  • If you cut yourself, apply pressure on the injury site until the bleeding stops.
  • If you take warfarin, make sure you go to your regular blood testing appointments for the INR follow-up. Ask your healthcare professional to inform you of the target INR range and note the results obtained (including the date of the test) to better monitor your treatment evolution.
  • Drink alcohol in moderation. If you take warfarin, alcohol can increase the risk of bleeding. If you take warfarin and your INR result is elevated, the healthcare professional who is monitoring your condition may ask you questions about your recent alcohol intake.
  • Always follow the dosage prescribed by your healthcare professional. Never increase or lower the dose. If dosage is not clear, ask your pharmacist to indicate it to you.

Your pharmacist—your safety net

Taking anticoagulants may generate questions and even concern. Isn't it reassuring to know that you can count on your pharmacist's expertise at all times? The role of pharmacists is to inform you, answer your questions, evaluate your therapy (including dosage, the risk of side effects, and interactions), identify potential and actual problems, ensure the necessary follow-up and speak with other healthcare professionals if required. They are your partners in achieving your therapeutic objectives and in bettering your health.

There is no doubt that taking an anticoagulant requires certain precautionary measures to ensure its safe use. Instead of worrying about it, ask for advice as often as is necessary from your pharmacist, who will help you implement the necessary measures to get the most benefits from your treatment.


Send to a friend

How to make safe use of anticoagulants

If you must take an anticoagulant, you may have some concerns about its use. The medications belonging to this class of drugs are safe and beneficial when a few important precautions are taken.