Health Tips

Know your blood thinners (Part 1)

Nobody likes a clogged toilet because it ceases to serve its functions: carry away dirty waste and channel clean, treated water to you. So what if your blood vessels are “clogged”?

When blood clots get dangerous (vein version)

Blood clotting is an amazing way for our body to deal with external injuries – it seals up the opening of your skin to limit blood loss and  it encourages the tissues surrounding the injury site to heal itself. When it has done its jobs, blood clots dissolve away. 

Animation of the formation of an occlusive thrombus in a vein. Image credit: ZYjacklin, Public domain, via Wikimedia Commons

However, if a blood clot forms inside a blood vessel, it can clog the vessel and keep blood from getting where it needs to go. When that happens to one of the veins deep within the leg, blood can back up and cause swelling and pain. This is known as deep vein thrombosis (DVT). Such blood clots can also travel via the blood vessels and end up blocking blood vessels in the lung, resulting in pulmonary embolism. This can make it hard to breathe and sometimes, when they are large, can lead to death. If you have irregular heartbeat and rhythm (atrial fibrillation), had just finished certain surgery procedures, or have installed mechanical valves onto your heart, you are also at risk of having abnormal blood clots in the body.

In Part 2, we will discuss what happens if a blood clot blocks the arteries in other parts of the body, such as your heart and brain.

Blood thinners to the rescue!

In general, there are two types of blood thinners:

1. Anticoagulants

2. Antiplatelets

To treat blood clots that block the vein in legs and lungs, or to prevent it from happening,your doctor may prescribe you with an anticoagulant. 

Know your anticoagulants

Anticoagulants are prescription medicines that make your blood less likely to clot. They can be taken orally as a pill; they can also be given as a shot or through a thin tube that goes into a vein, called an “IV”. Although anticoagulants are colloquially called blood thinners, they don’t actually thin the blood per se – they work by inhibiting a substance in our body that causes blood clotting called clotting factor.

Examples of commonly seen anticoagulants are:

Oral anticoagulants (Swallow the pills)

1. Warfarin 

2. Dabigatran (E.g. Pradaxa®)

3. Apixaban (E.g. Eliquis®)

4. Rivaroxaban (E.g. Xarelto®)

Parenteral anticoagulants (Given by injection or thin tube goes into the vein)

1. Enoxaparin (E.g. Clexane®)

2. Fondaparinux (E.g. Arixtra®)

3. Tinzaparin

Health risks of anticoagulants

The major risk is serious bleeding. That's because while these medicines help prevent dangerous blood clots, they also make it harder for your body to stop bleeding. This includes bleeding if you have an injury, but it could also be bleeding that happens without an injury (internal bleeding). So it's important to protect yourself from getting injured (such as during shaving, operating machineries and needles), and to get treatment as soon as possible if you have signs of bleeding. 

Image credit: http://www.phna.info/blood-tests-inr--blood-thinners.html

What do you need to do when you’re taking anticoagulant

Although the medicines mentioned above work in similar ways, they do have specific instructions that you should follow to ensure a successful treatment and minimized side effects. Your doctor or pharmacist will talk to you about what you need to do. Here are some general tips:

Recognise signs of bleeding

As we mentioned above, overdoing your anticoagulants can lead to unimaginable consequences such as major bleeding. This doesn’t mean that you should be scared of anticoagulants and stop taking them – that’s why taking your anticoagulant correctly is crucial; it prevents the blood clot from killing you, while at the same time minimize the bleeding risk.

You should also tell your doctor if you:

• Bleed from your gums after brushing your teeth

• Have heavy menstrual periods or bleeding between periods

• Have more bruising than usual after a minor injury

• Have diarrhea, vomit, or are unable to eat for more than 24 hours

As these may be signs that your anticoagulant has gone a little bit overboard.

If you cannot take your medicine for any reason, contact your doctor as well.

However, if you experience any of the following, call your doctor right away or visit an Emergency Department:

• Took more medicine than you were supposed to

• Have a serious accident or fall, hit your head, or get another injury that could cause bleeding

• Have any of these possible signs of abnormal bleeding:

  • Feeling sick to your stomach or throwing up blood or something that looks like coffee grounds

  • Blood in your bowel movements or dark-colored bowel movements

  • Headaches, dizziness, trouble talking, weakness, or loss of function of one of your arms or legs

  • Nosebleeds or any bleeding that does not stop

  • Dark red or brown urine

Internal bleeding can be life-threatening if not treated properly.

Know the strength of your medicine, what the pills look like, and why your doctor prescribed it for you 

Anticoagulants are not interchangeable. If your doctor prescribes warfarin to you, you should always take warfarin at the given strength and frequency. You should not switch to other types of anticoagulants without your doctor’s instructions. The colors of warfarin pills, for example, correspond to its strengths, and the combination may be different depending on the brands of warfarin. If the color, shape, or dose of your pills looks different from those you have taken before, check with your doctor or pharmacist.

Image credit: http://www.myhealth.gov.my/en/warfarin/

Take your medicine exactly as your doctor or pharmacist tells you to

Take your medicine at the same time each day, and follow strictly what your healthcare provider told you, such as:

• How often you take it-  It depends on which medicine you have. For dabigatran and apixaban it’s usually twice daily; whereas it's once daily for warfarin and rivaroxaban.

• When should you take it daily - For instance, Dabigatran should be taken with a full glass of water after a meal. Whereas you are advised to take rivaroxaban with food at the same time everyday, advisable with an evening meal. 

• What to do if you happened to miss a dose

Do not change your dose or stop your medicine without talking to your doctor. Always refill your prescription before you run out of pills. 

Get your blood tested when your doctor or pharmacist tells you to 

If you take warfarin, you will need to have your blood tested often at first to check how your blood is clotting. This test is called a "PT and INR". This is important in order to make sure you get the correct dose of warfarin for you. Once you are on a regular dose, you do not need to have a PT and INR test as often, unless your diet changes, you get sick, or you start a new medicine.

Follow your doctor's instructions about diet 

If you’re taking warfarin, there are certain do’s and don’ts for your daily diet. You will need to pay attention to the amount of vitamin K in your diet. You should eat about the same amount of vitamin K from foods every day. That means you should keep your consumption of vitamin K-rich foods as consistent as possible in your daily life. One example of vitamin-K rich foods is green,leafy vegetables.

Well, this has a lot to do with how warfarin works to prevent your blood from clotting. Vitamin K is one of the essential raw materials your body needs to make blood clot, and warfarin blocks the bodyfrom using vitamin K to clot your blood, thus reducing blood clot. The dose of warfarin and how often you should take it is personalised to you based on your previous blood test. If you’re taking warfarin, and suddenly you consume too much vitamin K from your diet, your warfarin won’t work as well and your are at risk of blood clotting; if you suddenly reduce your vitamin K intake, the warfarin would be ‘working too well’ and you may be at risk of bleeding! Oh, and avoid vitamin K supplements unless your doctor tells you to. 

Image credit: https://www.myfooddata.com/articles/food-sources-of-vitamin-k.php

Inform your healthcare professional that you’re taking an anticoagulant

It’s so, so important for you to inform your healthcare provider that you’re taking anticoagulants before trying any new medicines, over-the-counter drugs, traditional medicines, herbs, and dietary supplements. Not that we want to stop you from venturing into new things, but if you’re taking an anticoagulant,  some medicines might enhance its effects and put you at risk of bleeding. For instance, NSAIDs that people commonly use for pain and fever can increase your risk of bleeding if you’re taking it with an anticoagulant. If you’re going for any dental procedures, do inform your dentist that you’re taking an anticoagulant.

If you might be able to get pregnant, talk to your doctor 

Anticoagulants are not recommended during pregnancy. If you take one of these medicines and might be able to get pregnant, talk to your doctor about birth control options. It's also important to tell your doctor right away if you get pregnant while taking one of these medicines.

To be continued (Part 2)

A word from DOC2US

If you have any questions related to blood thinner medication, you can consult our professional doctors and healthcare professionals on DOC2US. DOC2US is a mobile application that allows you to talk to a doctor or any healthcare professionals via text chat at any time and from anywhere. For better communication, you can even send our online doctor images or voice messages related to your medical inquiry.

Download DOC2US app on Apple App Store, Google Play Store and Huawei App Gallery; or use our web chat at https://web.doc2us.com/

Note: DOC2US is not for medical emergencies. In the event of urgent medical conditions, please call 999.

Disclaimer: As a service to our users and general public, DOC2US provides health education contents. Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

References

1. Blood Thinners. Accessed April 25, 2021. https://medlineplus.gov/bloodthinners.html

2. Patient education: Choosing a medicine for blood clots (The Basics) - UpToDate. Accessed April 25, 2021. https://www.uptodate.com/contents/choosing-a-medicine-for-blood-clots-the-basics?search=Patient%20education:%20Staying%20safe%20while%20taking%20an%20oral%20medicine%20to%20prevent%20or%20treat%20blood%20clots%20(The%20Basics)&topicRef=15362&source=related_link

Cover image credit: Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436., CC BY 3.0, via Wikimedia Commons

Written by

Ms Joyce Toh