Clopidogrel: Mechanism and Indications

Overview

• Clopidogrel is an oral antiplatelet medication used to prevent blood clots in patients with acute coronary syndromes, recent myocardial infarction, or stroke.
• It belongs to the thienopyridine class of platelet inhibitors.

Mechanism of Action

• Inhibits the P2Y12 receptor on platelet surfaces, preventing platelet activation and aggregation.
• Activated by liver enzymes, specifically CYP2C19, to form an active metabolite.

Indications

• Acute coronary syndrome (ACS)
  • Unstable angina
  • Non-ST-segment elevation myocardial infarction (NSTEMI)
  • ST-segment elevation myocardial infarction (STEMI)
• Recent myocardial infarction
• Stroke
• Peripheral artery disease

Pharmacokinetics

• Rapid absorption after oral administration
• Peak plasma concentration reached within 2 hours
• Elimination half-life: 6-8 hours
• Metabolized by liver enzymes, primarily CYP2C19

Adverse Effects

• Bleeding (most common)
• Gastrointestinal upset (diarrhea, nausea, vomiting)
• Rash
• Headache
• Dizziness

Contraindications

• Active bleeding
• Allergy to clopidogrel
• Severe liver disease
• Pregnancy and breastfeeding (category B)

Interactions

• NSAIDs (increased risk of bleeding)
• Warfarin (increased risk of bleeding)
• CYP2C19 inhibitors (e.g., omeprazole, fluoxetine)
• CYP2C19 inducers (e.g., rifampin)

Dosing and Administration

• Standard dose: 75 mg once daily
• Loading dose: 300-600 mg (optional)
• Dose adjustments may be necessary for patients with severe liver disease or CYP2C19 poor metabolizers

Overview of Clopidogrel

• Oral antiplatelet medication used to prevent blood clots in patients with acute coronary syndromes, recent myocardial infarction, or stroke.
• Belongs to the thienopyridine class of platelet inhibitors.

Mechanism of Action

• Inhibits the P2Y12 receptor on platelet surfaces, preventing platelet activation and aggregation.
• Activated by liver enzymes, specifically CYP2C19, to form an active metabolite.

Indications for Use

• Acute coronary syndrome (ACS), including unstable angina, non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI).
• Recent myocardial infarction.
• Stroke.
• Peripheral artery disease.

Pharmacokinetics

• Rapid absorption after oral administration.
• Peak plasma concentration reached within 2 hours.
• Elimination half-life: 6-8 hours.
• Metabolized by liver enzymes, primarily CYP2C19.

Adverse Effects

• Bleeding (most common adverse effect).
• Gastrointestinal upset, including diarrhea, nausea, and vomiting.
• Rash.
• Headache.
• Dizziness.

Contraindications

• Active bleeding.
• Allergy to clopidogrel.
• Severe liver disease.
• Pregnancy and breastfeeding (category B).

Interactions

• NSAIDs increase the risk of bleeding.
• Warfarin increases the risk of bleeding.
• CYP2C19 inhibitors (e.g., omeprazole, fluoxetine) decrease the effectiveness of clopidogrel.
• CYP2C19 inducers (e.g., rifampin) increase the effectiveness of clopidogrel.

Dosing and Administration

• Standard dose: 75 mg once daily.
• Loading dose: 300-600 mg (optional).
• Dose adjustments may be necessary for patients with severe liver disease or CYP2C19 poor metabolizers.

Quiz on clopidogrel, an oral antiplatelet medication used to prevent blood clots in patients with acute coronary syndromes, recent myocardial infarction, or stroke.