uld start with two capsules once a day. The capsules should be swallowed whole with water.
A lower dose (150 mg once a day) is used in patients with mild or moderate kidney problems, in patients over 75 years of age, and in patients taking amiodarone (a medicine used to regulate the heart rhythm). Pradaxa should not be used in patients who have severe problems with their kidneys and it is not recommended for use in patients with signs of existing liver problems. Pradaxa should be used with caution in patients at risk of bleeding or who could have high blood levels of the medicine, such as those who have moderate problems with their kidneys. Patients weighing less than 50 kg or more than 110 kg should be closely monitored for signs of bleeding or anaemia (low red blood cell counts).
How does it work?
Patients undergoing hip or knee replacement surgery are at a high risk of blood clots forming in the veins. These clots, which include deep vein thrombosis (DVT), can be dangerous if they move to another part of the body such as the lungs or the brain. The active substance in Pradaxa, dabigatran etexilate, is a ‘prodrug’ of dabigatran. This means that it is converted into dabigatran in the body. Dabigatran is an anticoagulant, meaning that it prevents the blood from coagulating (clotting). It blocks a substance called thrombin, which is central to the process of blood clotting, reducing the risk of blood clots forming in the veins.
How has it been studied?
The effects of Pradaxa were first tested in experimental models before being studied in humans. The effectiveness of Pradaxa was studied in two main studies, both of which compared Pradaxa (either 220 or 150 mg a day) with enoxaparin (another anticoagulant). The first study involved a total of 2,101 patients who had had a knee replacement operation, and the second involved a total of 3,494 patients who had had a hip replacement. In both studies, the main measure of effectiveness was the number of patients who formed blood clots in the veins or who died of any cause during the treatment period. In most cases, blood clot formation was detected using scans of the veins or by looking for signs of blood clots in the lungs.
What benefits has it shown during the studies?
In both studies, Pradaxa was as effective as enoxaparin in preventing the formation of blood clots or death. In the study of patients undergoing knee replacement, blood clots were detected in 182 (36%) of the 503 patients taking the 220-mg dose of Pradaxa, compared with 192 (38%) of the 512 receiving enoxaparin. There was only one death in each group (less than 1%).
After hip replacement, blood clots were detected in 50 (6%) of the 880 patients taking 220 mg Pradaxa, compared with 60 (7%) of the 897 receiving enoxaparin. Three patients in the Pradaxa group died (less than 1%), but two of these deaths were unrelated to blood clots.
In both studies, the 220-mg dose showed a trend towards being more effective than the 150-mg dose.
What is the risk associated?
The most common side effect with Pradaxa (seen in more than 1 patient in 10) is bleeding. For the full list of all side effects reported with Pradaxa, see the Package Leaflet.
Pradaxa should not be used in people who may be hypersensitive (allergic) to dabigatran etexilate or any of the other ingredients. It should not be used in patients who have severe problems with their kidneys, active significant bleeding, tissue damage that could lead to bleeding, problems with the blood clotting process (this may be inborn, of unknown cause or
