Description and Composition of Pidogrel
Pidogrel contains Clopidogrel Bisulfate as its active pharmaceutical ingredient in addition to other inactive ingredients called excipients in sufficient quantities.
Clopidogrel is a thienopyridine class inhibitor of P2Y12 ADP platelet receptors. Clopidogrel is an Inhibitor of platelet aggregation. Variety of drugs that inhibit platelet function have been shown to decrease morbid events in people with established cardiovascular atherosclerotic disease as evidenced by stroke or transient ischemic attacks, myocardial infarction, unstable angina or the need for vascular bypass or angioplasty. This indicates that platelets participate in the initiation and/or evolution of these events and that inhibiting them can reduce the event rate. Clopidogrel selectively inhibits the binding of adenosine diphosphate (ADP) to its platelet receptor and the subsequent ADP-mediated activation of the glycoprotein GPllb/llla complex, thereby inhibiting platelet aggregation.
Indications and Uses of Pidogrel
What is Pidogrel used for?
Clopidogrel is indicated for the reduction of atherothrombotic events as follows:
Recent MI, Recent Stroke or Established Peripheral Arterial Disease
For patients with a history of recent myocardial infarction (MI), recent stroke, or established peripheral arterial disease, clopidogrel bisulfate has been shown to reduce the rate of a combined endpoint of new ischemic stroke (fatal or not), new MI (fatal or not), and other vascular death.
Acute Coronary Syndrome
For patients with acute coronary syndrome (unstable angina/non-Q wave MI) including patients who are to be managed medically and those who are to be managed with percutaneous coronary intervention (with or without stent) or CABG, clopidogrel bisulfate has been shown to decrease the rate of a combined endpoint of cardiovascular death, MI, or stroke as well as the rate of a combined endpoint of cardiovascular death, MI, stroke, or refractory ischemia.
Contraindications of Pidogrel
The use of clopidogrel bisulfate is contraindicated in the following conditions:Hypersensitivity to the drug substance or any component of the product. Active pathological bleeding such as peptic ulcer or intracranial hemorrhage.
Warnings about Pidogrel
Thrombotic thrombocytopenic purpura (TTP) has been reported rarely following use of clopidogrel bisulfate, sometimes after a short exposure (<2 weeks). TTP is a serious condition that can be fatal and requires urgent treatment including plasmapheresis (plasma exchange). It is characterized by thrombocytopenia, microangiopathic hemolytic anemia (schistocytes [fragmented RBCS) seen on peripheral smear), neurological findings, renal dysfunction, and fever,
Precautions to take while taking Pidogrel
Clopidogrel prolongs the bleeding time and therefore should be used with caution in patients who may be at risk of increased bleeding from trauma, surgery, or other pathological conditions (particularly gastrointestinal and intraocular). If a patient is to undergo elective surgery and an antiplatelet effect is not desired, clopidogrel bisulfate should be discontinued 5 days prior to surgery. Due to the risk of bleeding and undesirable hematological effects, blood cell count determination and/or other appropriate testing should be promptly considered, whenever such suspected clinical symptoms arise during the course of treatment
Use in Hepatically Impaired Patients:
Experience is limited in patients with severe hepatic disease, who may have bleeding diatheses. Clopidogrel bisulfate should be used with caution in this population
Use in Renally Impaired Patients:
Experience is limited in patients with severe renal impairment. Clopidogrel should be used with caution in this population.
Drug Interactions with Pidogrel
Aspirin did not modify the clopidogrel-mediated inhibition of ADP-induced platelet aggregation.
Concomitant administration of 500 mg of aspirin twice a day for 1 day did not significantly Increase the prolongation of bleeding time induced by clopidogrel bisulfate. Clopidogrel bisulfate potentiated the effect of aspirin on collagen-induced platelet aggregation. Clopidogrel bisulfate and aspirin have been administered together for up to one year.
In a study in healthy volunteers, Clopidogrel did not necessitate modification of heparin dose or alter the effect of heparin on coagulation. Coadministration of heparin had no effect on inhibition of platelet aggregation induced by clopidogrel bisulfate.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs):
In healthy volunteers receiving naproxen,
concomitant administration of Clopidogrel was associated with Increased occult gastrointestỉnal blood loss. NSAIDS and Clopidogrel should be coadministered with caution
Adverse Reactions of Pidogrel
What are the side effects or adverse reactions of Pidogrel?
The overall tolerability of Clopidogrel Bisulfate in CAPRIE was similar to that of aspirin regardless of age, gender and race, with an approximately equal incidence (13%) of patients withdrawing from matment because of adverse reactions.
Hemorrhagic: In CAPRIE patients receiving clopidogrel, gastrointestinal hemorrhage occürred at a rate of 2%, and required hospitalization in 0.7%. In patients receiving aspirin, the corresponding rates were 2.7% and 1.1%, respectively. The incidence of intracranial hemorrhage was 0.4% for clopidogrel bisulfate compared to 0.5% for aspirin. In CURE, Clopidogrel use with aspirin was associated with an increase in bleeding compared to placebo with aspirin. There was an excess in major bleeding in patients receiving clopidogrel bisulfate plus aspirin compared with placebo plus aspirin, primarily gastrointestinal and at puncture sites.
Overdosage of Pidogrel
Overdose following Clopidogrel administration may lead to prolonged bleeding time and subsequent bleeding complications. A single oral dose of clopidogrel at 1500 or 2000 mg/kg was lethal to mice and to rats and at 3000 mg/kg to baboons. Symptoms of acute toxicity were vomiting (in baboons), prostration, difficult breathing, and gastrointestinal hemorrhage in all species
Pidogrel Usage in Nursing Mothers
Can Pidogrel be used by breastfeeding women?
Studies in rats have shown that Clopidogrel and/or its metabolites are excreted in the milk. It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the nursing woman.
Can Pidogrel be used in children
Safety and effectiveness in the pediatric population have not been established.
Dosage and Administration of Pidogrel
What is the dosage of Pidogrel?
Recent MI, Recent Stroke or Established Peripheral Arterial Disease, the recommended daily dose of Clopidogrel tablets is 75 mg once daily.
Acute Coronary Syndrome : For patients with acute coronary syndrome (unstable angina/non-Q-wave MI), Clopidogrel should be initiated with a single 300 mg loading dose and then continued at 75 mg once daily. Aspirin (75 mg to 325 mg once daily) should be initiated and continued in combination with Clopidogrel (clopidogrel bisulfate). In CURE, most patients with Acute Coronary Syndrome also received heparin acutely. Clopidogrel tablets can be administered with or without food.
No dosage adjustment is necessary for elderly patients or patients with renal disease.
Storage of Pidogrel
Store below 30°C. Protect from direct sun light.
Keep out of reach of children.