Information for patients
This leaflet can be made available in other formats including large print, CD and Braille and in languages other than English, upon request.
Your Doctor has recommended that you start taking a medicine known as an anticoagulant or “blood thinner”.
This leaflet will tell you about different anticoagulants, such as Apixaban, Warfarin and Tinzaparin.
What are anticoagulants?
Anticoagulants are drugs used to reduce your body’s ability to form blood clots.
Why do I need to take an anticoagulant?
Your Doctor may recommend that you start using anticoagulants if you have any of the following health conditions:
- If you have developed a blood clot in the vein, such as a Deep Vein Thrombosis (DVT), which commonly affects your lower leg.
- If you have developed a Pulmonary Embolism (PE) in your lung.
- If you have a heart condition called Atrial Fibrillation (an irregular heartbeat), to help reduce your chance of developing a stroke (a blood clot in your brain).
- If you have had surgery or cancer and your Doctor believes you are at risk of developing blood clots.
- If you have been unwell and are walking or moving around much less than you normally would.
- If you have an inherited illness (genetic condition) that makes your blood clot more easily.
- If you have had an operation to replace a heart valve, especially if it is a metal valve.
There may be other reasons why your Doctor has recommended anticoagulants and this will be explained to you clearly before taking them. If you have any doubts, ask your Doctor before taking an anticoagulant.
Are there different types of anticoagulant?
The most commonly used anticoagulants at North Tees and Hartlepool NHS Foundation Trust are:
- Apixaban (brand name Eliquis®) – This is a tablet usually taken orally once or twice a day.
- Warfarin – This is a tablet (or tablets) usually taken orally once a day. The dose will vary based on blood tests.
- Tinzaparin – A low-molecular weight heparin (LMWH), which is given using a small injection into the fat below the skin, often in the tummy. This may be given once or twice a day. This is the most common medicine given to people while in hospital to try to prevent blood clots forming.
What dose of anticoagulant will I take?
The exact dose of anticoagulant, and how often it should be taken may vary from person to person and you should follow the specific instructions given to you by your Doctor.
Your anticoagulant should be taken around the same time each day. It is a good idea to set an alarm if you think you may struggle to remember.
For how long will I need to take this medicine?
Depending on the reason that you are taking an anticoagulant, you may only need it for a short time (such as a few weeks or months), or it may be required lifelong. This will be discussed with you by the Doctor prescribing the medication.
Will I still be given an anticoagulant if I am already taking medicine to thin my blood?
You may already be taking medicines, such as aspirin, clopidogrel, dipyridimole or ticagrelor. These medicines do thin your blood, but in a different way to anticoagulants. You may still be asked to continue these medicines while taking an anticoagulant, depending on the reason these other medicines have been prescribed.
These medicines can be taken at the same time as an anticoagulant, but can increase the risk of bleeding (see the section below on bleeding and side effects) and this risk should be considered before starting an anticoagulant.
Are there any reasons why I should not be given an anticoagulant?
Some people may not be suitable to take an anticoagulant, or they may need a different dose than would normally be prescribed.
It may not be suitable to take anticoagulants if you:
- Have chronic kidney or liver disease
- Have stomach or bowel ulcers or fragile veins in your stomach or oesophagus (gullet)
- Have problems in your arteries and veins such as aneurysms or arteriovenous malformations (unusual connections between arteries and veins)
- Have high blood pressure which hasn’t responded to treatment
- Have conditions that cause them to bleed easily (such as haemophilia)
- Are pregnant (see pregnancy section)
- Have already been given medicine that increases the risk of bleeding
- Have a condition called antiphospholipid syndrome.
Please let your Doctor know if any of the above apply to you before starting an anticoagulant.
You should also tell your Doctor if you:
- Have recently or previously had a stroke
- Have had surgery or a procedure (especially on the brain, spine or eyes)
- Have had a large bleed (such as following giving birth or from the stomach)
- Are planning to have surgery or a procedure in the future.
The benefits and risks of starting an anticoagulant should be considered by you and your Doctor together before you start taking it.
Different anticoagulants may be more suitable if you have any of the health conditions mentioned, and so it may still be possible to start taking an alternative anticoagulant.
Am I at an increased risk of bleeding when taking an anticoagulant?
All anticoagulant medicine will increase your risk of bleeding as it affects your body’s ability to make blood clots. This is the most important and potentially severe side effect.
It is common to experience minor bleeding such as:
- Small cuts bleeding for longer than usual. In this case, apply firm pressure for 5-10 minutes continuously
- Bleeding from gums while brushing teeth
- Bruising easily
- Heavier periods than normal for women
- Nosebleeds (lasting less than 10 minutes). In this case, pinch your nose just above the nostrils for 10 to 15 minutes continuously and lean forward.
In these cases, bleeding should stop by itself and you should continue to take your anticoagulant. If bleeding becomes regular and continuous, consider talking to your General Practitioner.
Occasionally, more serious bleeding can occur. Signs of serious bleeding include:
- Blood coming up when you vomit or cough.
- Blood coming from your anus (back passage)
- Visible blood or redness to your urine
- A change in your stools (poo). They may become black, smelly, loose and tar-like (called “melena”)
- Severe headaches, change in your vision or seizures (fits)
- Severe abdominal (stomach) pain
- Significant bruising without a history of injury (spontaneous) or bruising that spreads
- Prolonged bleeding – such as a nosebleed over 10 minutes or a cut where you cannot slow down the bleeding with firm pressure and advice above
What should I do if I notice any bleeding?
If you experience any of the serious symptoms above, you should immediately contact your usual Doctor or anticoagulation clinic. You should go to Accident and Emergency out-of-hours if you feel unwell.
These symptoms may indicate a serious or even life threatening bleed and may need urgent investigation or treatment.
You should also call 999 or attend Accident and Emergency if you are involved in a traumatic injury (such as a car crash or a fall down the stairs) or if you experience a head injury.
This is because taking anticoagulation increases your risk of internal bleeding or bleeding within the brain. This may not be obvious and you should be seen urgently by a medical professional.
For this reason, it is also advised you avoid contact sports or activities at high risk of injury. However you can still take part in non-contact sports such as tennis, running, cycling and badminton (see sports section below).
In cases of serious bleeding above, there are medications available to reverse or counteract the effects of your anticoagulation that will be considered by the medical team.
If you are unsure what to do, call the NHS helpline on 111 at any time of day to discuss your concerns.
What should I do if I am having a procedure or surgery?
If you are having a procedure, operation or dental work, the team that is planning the procedure will need to know you are taking an anticoagulant.
You will normally be asked about your medication before having any procedure, however if you are not asked, please make sure you tell the team. This will allow them to plan the best way to stop your anticoagulant before the procedure.
Are there any other side effects?
All medicines we take can potentially cause side effects, but this does not mean that everyone will experience them.
As well as the risk of bleeding, common side effects from anticoagulants include:
- Low blood count (low haemoglobin levels) causing anaemia. You may feel tired, short of breath, pale, experience dizziness or palpitations (noticeable changes to your heartbeats)
- Feeling sick (nausea)
Warfarin can occasionally cause hair loss. Warfarin can also cause liver damage, but this is very rare. You should see your General Practitioner immediately if you notice yellowing of your eyes or skin or pale stools.
Tinzaparin can cause the platelet levels in your blood to fall (thrombocytopenia), which can cause spontaneous bruising, a pin-prick like rash or bleeding gums, but this is rare.
Contact your General Practitioner immediately if you notice these symptoms while taking Tinzaparin.
For a full list of side effects, see the further information section at the end of this leaflet, or read the patient information leaflet provided in the box with the medication you are given.
You can also report side effects directly via the Yellow Card Scheme:Yellow Card Scheme
Can I stop taking my anticoagulant?
If you experience any of the side effects mentioned, you should tell your General Practitioner, anticoagulation clinic or your usual Doctor. It may be possible to stop, reduce or change your anticoagulant.
If you stop suddenly without support from a medical professional, you may suffer serious and even life threatening consequences.
If you are experiencing significant bleeding as described above, do not take any further doses of your anticoagulant and seek urgent medical attention as mentioned.
You may also be asked to stop, reduce or change your anticoagulant for a period before or after surgery, or a procedure. This should be clearly explained to you before the procedure. Failure to follow these instructions may delay or lead to cancellation of your procedure.
Can anticoagulants affect any of my other medicines?
Yes. Some anticoagulants (especially warfarin) can interact with other medicines.
These can include antibiotics, epilepsy medication, non-steroidal anti-inflammatory medication (such as ibuprofen) and other medications that increase the risk of bleeding or the way the body interacts with your anticoagulant.
If a Doctor or Practitioner is planning to start you on a new medicine, you should tell them you are taking anticoagulants so that they can make sure they are safe to take together.
You should also be very careful with any medicine that you buy over the counter such as aspirin, ibuprofen, paracetamol, vitamins, supplements and herbal remedies (especially St John’s Wort).
This medication can interact with anticoagulants and/or increase your risk of bleeding from your stomach. Discuss these medications with your Pharmacist or your General Practitioner before starting them. You must always follow the information leaflet provided with any new medication before taking it if you are unsure.
What monitoring is required when taking an anticoagulant?
If Tinzaparin or Apixaban is only taken for short periods, you will not need routine monitoring. A blood test to check your kidney function and haemoglobin levels should be checked before you start taking this medicine.
These levels may be checked routinely if you need anticoagulants for long periods, to ensure that they are safe to take at your current dose.
Is there anything I should know about when taking Warfarin?
Warfarin requires a regular blood test called the International Normalised Ratio (INR), which looks at how thick or how thin your blood is and how long it takes to clot. People who are not prescribed warfarin will typically have an INR of 0.8-1.2 (with an average value of 1.0).
When first starting warfarin, this will usually be checked once a day, and the dose of warfarin you need to take each day will often change. Your Doctor or Anticoagulation Nurse will inform you of the required dose once the INR is checked.
The frequency of blood tests will gradually decrease as your body becomes used to the dose of warfarin, but will always need to be checked at a minimum of every 12 weeks.
This is to ensure your INR remains within the target range (often 2.0 to 3.0 – though this may vary, depending on the reason you are taking warfarin).
If it is too low, the warfarin is not effective and your blood is more likely to clot causing potentially serious complications. If it is too high, you are at increased risk of serious bleeding, as your blood is less able to form clots. Because of this, it is essential to attend your regular INR checks when they are offered to you.
Warfarin is provided in different strength tablets which can be taken together to achieve the desired dose: 0.5mg (white), 1mg (brown), 3mg (blue), 5mg (pink). It is always important before taking a dose of warfarin that you check you are taking the correct tablets.
Your body’s natural clotting proteins and your ability to absorb warfarin can be affected by illness, which will make your INR level less stable.
If you suffer from fever, viral illness or prolonged diarrhoea and vomiting, or if you are unable to take your medication for any reason, you should inform your General Practitioner immediately, as extra INR tests may be required.
It is very important to consider how warfarin affects any other medications you are taking.
If you start taking a new medicine, it is important to inform your Anticoagulant Clinic.
Warfarin can also be affected by diet:
- Foods high in vitamin K such as dark green leafy vegetables (broccoli, spinach, cabbage, Brussels sprouts) can make warfarin less effective and reduce the INR
- Grapefruit juice and other fruit juices may make warfarin more potent and increase the INR when taken in large quantities
- Alcohol can also make the effects of warfarin more potent and increase your risk of bleeding from the stomach
Because of this, it is important to either avoid the foods above or, if preferred, make sure that you have a stable intake and avoid dramatic changes in your diet or alcohol consumption.
You can drink alcohol while taking anticoagulants, but you must not drink more than 14 alcohol units a week (see alcohol section below).
You will be given a yellow book, alert card and/or a warfarin-monitoring chart. It is important to keep these with you so that people know you are on warfarin and your usual dose can be known in an emergency.
Is there anything I should know about taking Tinzaparin?
Tinzaparin is given as an injection into the area just below the skin (the subcutaneous fat). The needles used are small and are usually painless. Administering tinzaparin is simple and can usually be carried out by the patient themselves, their carer or a District Nurse.
Ask your Doctor or Nurse to show you how to administer tinzaparin, or see the further information section at the end of this leaflet for detailed guidance.
Each time a needle is used to administer tinzaparin, the needle must be discarded safely using a yellow “sharps bin”. This should be provided by the hospital or your Community Health Trust and disposed of safely by your local surgery or pharmacist once full. Do not throw needles or a sharps bin in normal domestic waste.
What if I am pregnant or breastfeeding?
Some anticoagulants (such as apixaban) are not suitable for pregnant women as there is limited information on their safety.
Low molecular weight heparins, such as tinzaparin, are generally considered more suitable during pregnancy and are recommended by national bodies.
Your Doctor may consider using these, or a different anticoagulant such as heparin, following discussion with a specialist if an anticoagulant is needed while you are pregnant or breastfeeding.
This can be done even if the medication is not licensed, as it may still be safe to use.
What if I miss a dose or take too much?
It is important to try to take your medication at the same time each day, to reduce the risk of side effects and to make your anticoagulant as effective as possible.
If you forget to take your anticoagulant, you should take it as soon as you remember, unless it is nearly time for your next dose. If this is the case, take your next dose of anticoagulant as normal and tell your General Practitioner or Anticoagulation Clinic as soon as possible. If you are taking warfarin, you may need extra INR tests.
If you do forget your medication, never double your next dose. You should only take the dose that has been recommended.
If you accidentally take a larger dose of your anticoagulant than you are meant to, you should seek urgent medical assistance from your General Practitioner or phone 111 out of hours, as you are at an increased risk of bleeding.
If you are having problems with frequently missing your medication, discuss with your Pharmacist or General Practitioner, as there may be ways to help you to remember your medication, avoiding serious consequences of missed or double doses.
Is it safe to drink alcohol while taking an anticoagulant?
It is generally safe to consume small amounts of alcohol within the government recommended limits while taking an anticoagulant. Despite this, the safest option is to avoid alcohol as much as you can while using blood anticoagulants.
If you are pregnant or there is a chance you might be pregnant, it is advised that you avoid alcohol.
Regular consumption of more than the recommended limits or excessive binges can affect the way your liver interacts with medications.
This can make them less effective or make them more potent and the side effects (such as bleeding) more likely.
This is particularly true of warfarin (this is discussed in more detail in the warfarin specific section).
Drinking alcohol over the recommended limit also increases your risk of developing an ulcer or bleeding in your stomach. Excessive alcohol may also lead to falls and head injuries.
If you are taking an anticoagulant, this bleeding may be more serious, and so it is important to avoid exceeding the safe alcohol limit.
Is it safe to fly while taking an anticoagulant?
These medications are safe to take while flying.
Long flights can increase your risk of developing clots in the vein. If you are taking anticoagulants because you are at risk of developing clots, you should discuss whether it is safe to fly with your Doctor before planning a flight.
Your Doctor will tell you what other measures can be taken to reduce your risk (such as wearing compression stockings).
If you are taking an anticoagulant because of a clot on the lung (pulmonary embolism), then your lungs may struggle to get enough oxygen into your body. It may not be safe to fly and you should ask your Doctor before planning a flight.
If you are going on holiday, make sure you take enough medication and have appropriate insurance for your medical needs.
Is it safe to play sports while taking an anticoagulant?
Because of the increased risk of serious bleeding, people taking anticoagulants should avoid contact sport (such as rugby) or activities at high risk of injury (such as rock climbing or motorcross).
What should I do if I suffer a head injury?
If you suffer any form of head injury while using anticoagulants, you should seek medical advice immediately. This is because any bleeding is much more serious while using this medication.
There are several sources of detailed, reliable information specific to anticoagulants available to you:
The NHS website has useful, easy to read information on a range of topics related to anticoagulation:Anticoagulants Apixaban Warfarin
Information on how to administer Tinzaparin can be found below:Tinzaparin administration
You will find detailed and specific medicine information sheets provided with your medication, which you should read fully before starting. This information and more can also be found at:Electronic Medicines Compendium
If you are ever unsure, call your general practitioner or 111 for advice.
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Leaflet reference: PIL1323
Date for review: 9 June 2024