Drug Guide
Clopidogrel Bisulfate
Classification
Therapeutic: Antiplatelet agent
Pharmacological: P2Y12 inhibition
FDA Approved Indications
- Prevention of stroke, myocardial infarction, and vascular death in patients at risk; Treatment of acute coronary syndrome (ACS) including unstable angina and myocardial infarction
Mechanism of Action
Clopidogrel is an irreversible antagonist of the P2Y12 ADP receptor on platelets, inhibiting platelet aggregation and preventing thrombus formation.
Dosage and Administration
Adult: Typically 75 mg once daily, with or without food; for acute coronary syndrome, initial dosing may be 300 mg loading dose followed by 75 mg daily.
Pediatric: Not established; only approved for certain pediatric conditions under specific circumstances.
Geriatric: Use with caution due to increased bleeding risk; no specific dose adjustment but monitor closely.
Renal Impairment: Careful use; no specific dose adjustment, but bleeding risk increases.
Hepatic Impairment: Use with caution; no specific dose adjustment.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Extensively bound to plasma proteins (~98%).
Metabolism: Prodrug activated primarily by CYP2C19; also involves CYP1A2, CYP2B6, and others.
Excretion: Metabolites excreted mainly in urine.
Half Life: Approximately 6 hours for the active metabolites; platelet inhibition lasts for the lifespan of the platelet (~7-10 days).
Contraindications
- Active pathological bleeding (e.g., peptic ulcer, intracranial hemorrhage)
Precautions
- History of bleeding disorders, hepatic impairment, recent surgery or trauma
Adverse Reactions - Common
- Bleeding, including subdural hematoma (Common)
- Bruising, bleeding at injection site (Common)
Adverse Reactions - Serious
- Thrombotic thrombocytopenic purpura (TTP) (Rare but serious)
- Major bleeding events (Serious)
Drug-Drug Interactions
- Proton pump inhibitors, especially omeprazole and esomeprazole, as they may reduce effectiveness by inhibiting CYP2C19.
- Other anticoagulants and antiplatelet agents increase bleeding risk.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for signs of bleeding, bleeding times, and platelet counts.
Diagnoses:
- Risk for bleeding
- Ineffective tissue perfusion related to bleeding
Implementation: Administer as prescribed; educate patient on bleeding precautions.
Evaluation: Assess for signs of bleeding and ensure therapeutic effectiveness.
Patient/Family Teaching
- Report any unusual bleeding or bruising.
- Use caution with activities that could cause injury.
- Inform about the importance of adherence to therapy.
Special Considerations
Black Box Warnings:
- Increased risk of significant bleeding.
- Thrombotic thrombocytopenic purpura (TTP)—a rare but serious condition that can occur within 2 weeks of starting therapy.
Genetic Factors: CYP2C19 genetic polymorphisms can affect drug metabolism and response.
Lab Test Interference: Can prolong bleeding time tests.
Overdose Management
Signs/Symptoms: Excessive bleeding, bruising, hematomas.
Treatment: Discontinue drug; supportive care; platelet transfusions in severe cases.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable until the expiration date on the packaging.