What is Plavix?
Plavix is a medicine that contains the active substance clopidogrel. It is available as pink tablets (round: 75 mg; oblong: 300 mg).
What is Plavix used for?
Plavix is indicated in the prevention of atherothrombotic events (problems due to blood clots and hardening of the arteries) in adults. Plavix can be given to the following groups of patients:
- patients who have recently had a myocardial infarction (heart attack). Treatment with Plavix can be started in the period between a few days and 35 days after the heart attack;
- patients with recent ischemic stroke (attack caused by insufficient blood supply to an area of the brain). Treatment with Plavix can be started between seven days and six months after the stroke;
- patients with peripheral arterial disease (problems with blood circulation in the arteries);
- patients suffering from a disorder known as "acute coronary syndrome", to which the medicine is administered with aspirin (another medicine to prevent the formation of clots), including patients who have been implanted with a stent (a small tube inserted in an artery to prevent clogging). Plavix can be used in patients who have a heart attack with "ST-segment elevation" (an abnormal reading on the electrocardiogram or ECG) when the doctor thinks the treatment may be beneficial. It can also be used in patients who do not have this abnormal ECG reading, when suffering from unstable angina (a severe form of chest pain) or myocardial infarction "without Q waves".
The medicine can only be obtained with a prescription.
How is Plavix used?
The standard dose of Plavix is one 75 mg tablet once a day, with or without food. In acute coronary syndrome, Plavix is used together with aspirin and treatment generally begins with a loading dose of one 300 mg tablet or four 75 mg tablets. This dose is then followed by the standard dose of 75 mg once a day for at least four weeks (in myocardial infarction with elevation of the ST segment) or up to 12 months (in the presence of a syndrome without elevation of the ST segment).
Within the body Plavix is converted into the active form. For genetic reasons, some individuals are unable to convert Plavix as effectively as other patients, which may lower the degree of response to the medicine. The most suitable dose for this type of patient has not yet been identified.
How does Plavix work?
The active substance in Plavix, clopidogrel, is an inhibitor of platelet aggregation, which means it helps prevent blood clots. Blood coagulation occurs following the action of special blood cells, the platelets, which aggregate (stick together). Clopidogrel blocks platelet aggregation by preventing a substance called ADP from binding to a specific receptor on their surface. This prevents the platelets from becoming "sticky", reducing the risk of blood clots forming and helping to prevent another heart attack or stroke.
How has Plavix been studied?
Plavix was compared with aspirin in a study called CAPRIE in about 19, 000 patients who had recently had a heart attack or an ischemic stroke or who had established peripheral arterial disease. The main measure of effectiveness was the number of patients who underwent a new "ischemic event" (heart attack, ischemic stroke or death) over a period of one to three years.
With regard to acute coronary syndrome, Plavix was compared with a placebo (a dummy treatment) in a study conducted on 12 000 patients with ST-segment-free syndrome, of which 2 172 underwent implantation of stent during the study (CURE study, lasted up to one year). Plavix was also compared with a placebo in two studies involving patients with ST segment elevation: the CLARITY study involved over 3, 000 patients and lasted up to eight days; the COMMIT study, which involved around 46, 000 patients, during which patients were given Plavix with or without metoprolol (another drug used for heart problems or high blood pressure) lasting up to four weeks. In the studies of acute coronary syndrome, all patients also took aspirin and the main indicator of effectiveness was based on the number of subjects going through an "event", for example an arterial block or another infarct, or who had died during the course of study.
What benefit has Plavix shown during the studies?
Plavix has been shown to be more effective than aspirin in preventing new ischemic events. During the CAPRIE study 939 events were recorded in the group treated with Plavix and 1 020 in the group treated with aspirin. This corresponds to a relative risk reduction of 9% compared with aspirin. "Risk reduction" means that the number of patients who undergo new ischemic events when treated with Plavix is lower than those treated with aspirin. In other words, about 10 out of 1, 000 patients will avoid a new ischemic event two years after starting Plavix therapy compared to those taking aspirin.
In the case of acute coronary syndrome without elevation of the ST segment, the overall relative risk reduction of one event compared to placebo was 20%. A reduction was also recorded in patients undergoing stent implantation. In the case of myocardial infarction with ST segment elevation, the number of patients treated with Plavix who had events was lower than those treated with placebo (262 compared to 377 in the CLARITY study and 2 121 compared to 2 310 in the COMMIT study). These results showed that Plavix reduces the risk of an event.
What are the risks associated with Plavix?
The most common side effects with Plavix (seen in between 1 and 10 patients in 100) are hematoma (collection of blood under the skin), epistaxis (nosebleeds), gastrointestinal haemorrhage (bleeding in the stomach or intestines ), diarrhea, abdominal pain, dyspepsia (indigestion), bruises and bleeding at the injection site. For the full list of all side effects reported with Plavix, see the Package Leaflet.
Plavix should not be used in people who may be hypersensitive (allergic) to clopidogrel or other ingredients in the medicine. Plavix should not be used in patients with severe liver disorders or diseases that can cause bleeding. For the full list of usage restrictions, see the package leaflet.
Why has Plavix been approved?
The Committee for Medicinal Products for Human Use (CHMP) decided that the benefits of Plavix outweigh the risks in the prevention of atherothrombotic events in adults. The Committee therefore recommended that Plavix be given marketing authorization.
More information about Plavix:
On 15 July 1998, the European Commission issued a marketing authorization for Plavix, valid throughout the European Union, to Sanofi Pharma Bristol-Myers Squibb SNC. The marketing authorization was renewed on 15 July 2003 and 15 July 2008.
The full EPPAR version of Plavix can be found here.
Last update of this summary: 09-2009.
