How does it work?
Pradaxa capsules contain the active ingredient dabigatran etexilate, which is a type of medicine called a direct thrombin inhibitor. It is used to stop blood clots forming within the blood vessels.
Blood clots usually only form to stop bleeding that has occurred as a result of injury to tissue in the body. However, after hip or knee replacement surgery there is a risk of blood clots forming in the blood vessels. This risk is increased by being immobile for long periods of time following the surgery, as a result of slowed blood flow in the leg and pelvic veins. A clot that forms in the veins of the leg is called a deep vein thrombosis. These dangerous blood clots can travel to the lungs, causing a serious condition called a pulmonary embolism.
People with a type of fast irregular heartbeat called atrial fibrillation (AF) are also at risk of blood clots forming, both within the heart and in the blood vessels. This is because the abnormal heart rhythm disrupts blood flow in the blood vessels. Clots in the heart can detach and travel to the brain, causing a stroke. Clots can also travel in and block other blood vessels around the body.
The blood clotting process is complicated. When blood begins to clot, a cascade of chemicals is activated within the body, resulting in the formation of an enzyme called thrombin. Thrombin is central to the complete process of blood clotting. It causes a protein called fibrinogen to be converted into another called fibrin. Fibrin binds blood cells called platelets together, and this forms the blood clot.
Dabigatran works by binding to thrombin in the clotting process described above and blocking its action. This stops the formation of fibrin, the essential component of blood clots. Dabigatran can therefore prevent blood clots from developing.
What is it used for?
- Preventing dangerous blood clots in the veins (venous thromboembolism) in adults who have undergone elective total hip or knee replacement surgery.
- Preventing the formation of blood clots that can cause a stroke or blockage of other blood vessels in the body in people with a type of irregular heartbeat called atrial fibrillation (AF). This medicine is licensed to prevent these types of blood clots in people with AF who have one or more of the following additional risk factors:
- a history of stroke or blood clots
- heart failure
- age over 75 years
- age over 65 years and either diabetes, high blood pressure or coronary artery disease.
How do I take it?
- Pradaxa capsules can be taken either with or without food.The capsules should be swallowed whole with water. They must not be opened or chewed because this dramatically increases the absorption of the medicine into the body and thus increases the risk of bleeding (see warning section below).
- The dose prescribed and how often the medicine needs to be taken depends on whether you are taking the medicine to prevent blood clots following surgery, or to prevent a stroke or other blood clot because you have AF. It is important to follow the instructions given by your doctor. These will be printed on the dispensing label that your pharmacist has put on the packet of medicine.
- If this medicine is being used to prevent blood clots following hip or knee replacement surgery, treatment should be started within one to four hours after the surgery, though this may be delayed if there are any complications with bleeding after surgery. The capsules are taken once daily for 10 days following a knee replacement and for 28 to 35 days following a hip replacement.
- Do not stop taking this medicine until you have been advised to by your doctor.
- As this medicine prevents blood clotting, the most common side effects associated with treatment involve bruising or bleeding. Not all people will experience side effects. However, it is important that you let your doctor know straight away if you notice any sign of bruising or bleeding while you are taking this medicine. This includes any signs of blood in your urine, coughing up blood, or any sign of bleeding from the stomach or intestine, for example vomiting blood and/or passing black/tarry/bloodstained stools. You should also get urgent medical advice if you fall or injure yourself, particularly if your hit your head, while taking this medicine, due to the increased risk of bleeding.
- It is important that you tell any health professional treating you, including your dentist, that you are taking this medicine. If you are due to have any surgery it is also important to talk to your doctor in advance about your medicine. For some surgery it is safe to keep taking dabigatran, whereas if you are going to have major surgery with a higher risk of bleeding your doctor may want you to stop taking your dabigatran up to four days before the surgery. Follow the instructions given by your doctor.
- Your doctor will want to check your kidney function before you start treatment, because some kidney problems may increase the risk of bleeding with this medicine. If you are taking this medicine on a long-term basis and you are over 75 years of age or have any existing kidney problems, your doctor will also want to check your kidney function at least once a year.
- This medicine contains sunset yellow food colouring, which may cause allergic reactions in some people.
Use with caution in
- Elderly people.
- People who weigh less than 50kg or more than 110kg.
- Decreased kidney function.
- Liver disorders.
- Bacterial infection of the heart valves and the lining surrounding the heart (bacterial endocarditis).
- People with heart disease.
- People with diabetes.
- People with an increased tendency to bleed, for example due to blood clotting disorders such as haemophilia.
- People with low numbers of blood cells called platelets in their blood (thrombocytopenia).
- People with inflammation in the stomach (gastritis), inflammation of the foodpipe (oesophagitis) or gastro-oesophageal reflux.
- People who have recently had a biopsy.
- People who have recently had a major injury.
- People having spinal or epidural anaesthesia or injection into the spine (lumbar puncture).
- People taking medicines that may increase the risk of bleeding, for example non-steroidal anti-inflammatory drugs (NSAIDs, eg diclofenac), SSRI antidepressants, eg fluoxetine, or antiplatelet medicines such as low dose aspirin or clopidogrel (see last section of factsheet for more examples).
Not to be used in
- People with active severe or dangerous bleeding.
- People with a disease or condition in an organ that significantly increases the risk of major bleeding, for example ulcerative diseases of the intestines such as peptic ulcer or ulcerative colitis, or cancers at high risk of bleeding.
- People with known or suspected oesophageal varices, which are dilated veins in the foodpipe that are usually a complication of liver cirrhosis.
- People with malformations or abnormalities of the blood vessels.
- People who have recently had any bleeding inside the skull.
- People who have recently had brain, spinal or eye surgery.
- People who have recently had a brain or spinal injury.
- People taking other anticoagulant medicines to treat or prevent blood clots, such as warfarin or heparin (except when switching treatment to or from Pradaxa).
- Severely decreased kidney function.
- Decreased liver function or liver disease that may be life-threatening.
- People with an artificial heart valve.
- This medicine is not recommended for people who have an indwelling catheter in their spine for pain relief after the surgery.
- This medicine is not recommended for people having surgery for a hip fracture.
- This medicine is not recommended for children and adolescents less than 18 years of age, as its safety and efficacy have not been established in this age group.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use during pregnancy has not been established. For this reason, it should not be used in pregnancy unless considered essential by your doctor, and only if the benefit of its use outweighs the risk to the unborn child. Women who could get pregnant should use a reliable method of contraception to avoid getting pregnant while taking this medicine. Seek further medical advice from your doctor.
- It is not known if this medicine passes into breast milk. The manufacturer states that women who need treatment with this medicine should not breastfeed while taking it. Seek further medical advice from your doctor.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Common side effects (affect between 1 in 10 and 1 in 100 people)
- Low red blood cell count (anaemia).
- Nose bleeds (epistaxis).
- Bleeding in the gut.
- Abdominal pain.
- Feeling sick.
- Bruising of the skin.
- Abnormal results in liver function tests.
Uncommon side effects (affect between 1 in 100 and 1 in 1000 people)
- Weeping of a surgical wound.
- Blood clots which form a solid swelling at the injection site (haematoma).
- Coughing up blood.
- Bleeding from the rectum.
- Bleeding from piles (haemorrhoids).
- Ulceration in the gut.
- Acid reflux.
- Difficulty or pain when swallowing.
- Blood in the urine (haematuria).
- Bleeding into a joint (haemarthrosis).
- Bleeding inside the skull.
- Bleeding underneath the skin.
- Bleeding after an operation or injury.
- Decrease in the number of platelets in the blood (thrombocytopenia).
- Rash or itching.
Rare (affect between 1 in 1000 and 1 in 10,000 people)
- Bleeding from an injection site.
- Bleeding from a catheter site.
- Nettle-type rash (urticaria).
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
This medicine must not be used in combination with the following medicines:
Dabigatran is not recommended for people taking protease inhibitors for HIV infection such as ritonavir.
This medicine will enhance the effect of other anticoagulant medicines used to treat and prevent blood clots, such as those listed below. For this reason, it should not be used in combination with these medicines (except if treatment is being switched to or from Pradaxa):
- heparins (unless this is being used to stop blood clots forming in a central line)
- low-molecular weight heparins, eg dalteparin, enoxaparin, tinzaparin
There may be an increased risk of bleeding if this medicine is used in combination with other medicines that can affect blood clotting, such as those listed below:
- aspirin (including low-dose aspirin to ‘thin the blood’)
- glycoprotein IIb/IIIa receptor antagonists, eg abciximab, eptifibatide and tirofiban
- non-steroidal anti-inflammatory drugs (painkillers such as diclofenac, ibuprofen, naproxen) - while you are taking this medicine you should only take these types of painkillers on the advice of a doctor
- SSRI antidepressants such as fluoxetine, fluvoxamine, paroxetine, citalopram
- thrombolytic agents (clot-busters), eg alteplase, streptokinase
The following medicines may increase the amount of dabigatran in the blood and so could increase the risk of side effects such as bleeding:
If you are taking any of these medicines in combination with dabigatran your doctor may need to prescribe you a lower than normal dose of dabigatran. They will also monitor you more closely, particularly for any signs of bleeding or anaemia.
The following medicines may reduce the amount of dabigatran in the blood and as a result could make it less effective. These should be avoided while you are taking dabigatran:
- the herbal remedy St.John’s wort (Hypericum perforatum).
Other medicines containing the same active ingredient
There are currently no other medicines available in the UK that contain dabigatran etexilate as the active ingredient.