Clopidogrel

Clopidogrel (Plavix®)

Class:
  • Antiplatelet agent
Actions:
  • Inhibits platelet activation by ADP by blocking ADP receptor sites on platelets
  • Irreversibly blocks platelet activation for life of platelet.
Indications:
  • Prevention of occlusion of coronary stents for patients who are having cardiac catheterization with angioplasty
  • Reduce thrombotic events in patients with history of MI, ACS, ischemic stroke, or peripheral vascular disease
  • Acute coronary syndrome (either with aspirin for STEMI or as an alternative to aspirin if patient is hypersensitive to aspirin for unstable angina or NSTEMI)
Pharmacokinetics:
  • Onset: 2 hours
  • Plateau:  3 – 7 days
  • Half-Life: 8 hours
Adverse Effects:
  • Abdominal pain, dyspepsia, diarrhea, rash
  • Bleeding: GI bleeding (melena, peptic ulcer), GU bleeding (blood in urine), epistaxis
  • Thrombotic thrombocytopenic purpura–rare
  • Intracranial bleeding (hemorrhagic stroke)–rare
Contraindications:
  • Bleeding disorders (peptic ulcer, hemorrhagic stroke)
  • Caution with patients taking other anti-clotting drugs (heparin, warfarin, etc.)
  • Caution with patients with hepatic impairment
  • Safety during pregnancy, lactation or with children not established (Category B).
Dosages & Routes:
  • PO: 300 mg initial dose followed by 75 mg daily
Nursing Implications:
  • Drug Interactions:  1) increased risk of bleeding with aspirin, NSAIDS, heparin, enoxaparin, and other anti-clotting drugs; 2) Omeprazole and other proton pump inhibitors  may decrease efficacy of clopidogrel; 3) Feverfew, garlic, ginger, and ginkgo may increase risk of bleeding.
  • Do not administer clopidogrel to ACS patients if CABG is planned within 5 – 7 days.  [Controversial evidence about this warning!]
  • Platelet function and bleeding time return to baseline in 7 – 10 days.
  • Monitor patient for signs of thrombotic thrombocytopenic purpura (low platelet count, neuro symptoms, renal dysfunction, fever).
  • Monitor for signs and symptoms of bleeding (urine, stool, hematoma, epistaxis, petechiae).
  • May cause elevation of serum liver enzymes–establish baseline enzymes and bilirubin levels.

References:

American Heart Association. (2006). Handbook of Emergency Cardiac Care (p. 48). Salem, MA: AHA.

American Heart Association. (2005). Stabilization of the patient with acute coronary syndromes.  Circulation, 112(24), IV-92-102.

Deglin, J.H., & Vallerand, A.H. (2009). Davis' drug guide for nurses (11th ed., pp. 324-325).  Philadelphia: F.A. Davis.

Lehne, R.A. (2010). Pharmacology for nursing care (7th ed., pp. 609-610).  St. Louis: Saunders Elsevier.

Wilson, B.A., Shannon, M.T., Shields, K.M., & Stang, C.L. (2007).  Prentice Hall Nurse's Drug Guide 2007 (pp. 401-402).  Upper Saddle River, NJ: Pearson Prentice Hall.

 

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