Focus on Error Prevention: Indications for Antiplatelet Therapy
By Ian Stewart B.Sc.Phm., R.Ph.
When reviewing prescriptions for appropriateness, pharmacists must consider the indication for use of the drug. It is difficult to confirm that the right patient is receiving the right drug at the right dose at the right time via the right route for the correct duration if the purpose of the medication is not known. Unfortunately this key piece of information is often missing.
A common indication for clopidogrel bisulfate is for the secondary prevention of atherothrombotic events (myocardial infarction, stroke and vascular death) in patients with atherosclerosis documented by stroke, myocardial infarction, or established peripheral arterial disease1.
Patients taking clopidogrel bisulfate may be asked to stop taking the medication for five to seven days before any planned surgery to minimize bleeding1.
However, for patients undergoing stent implantation surgery, antiplatelet therapy has been shown to reduce the risk of major adverse cardiac events including myocardial infarction, and the risk of death2.
Though excessive bleeding is a concern during stent implantation surgery, clotting or stent thrombosis is a more serious and potentially fatal problem.
Therefore, patients scheduled for diagnostic coronary angiography with the intent to perform percutaneous coronary interventions if the lesions are amenable to angioplasty will often be asked to begin antiplatelet therapy such as clopidogrel before the procedure to prevent major adverse cardiac events.
Case:
A sixty-two year-old patient with a strong family history of coronary artery disease has additional risk factors including diabetes and hypertension. The patient has experienced typical chest pain, but is still very active and an avid cyclist. He recently had a positive stress echocardiogram indicating ischemia in the mid to distal anterior and apical region, with the possibility of a left anterior descending coronary artery lesion.
The patient was referred for an angiogram to assess coronary anatomy and possible angioplasty if needed. His cardiologist prescribed a 300mg loading dose of clopidogrel, then 75mg by mouth once daily to begin immediately. The prescription was taken to his community pharmacy for processing.
During patient counselling, the patient was told by the pharmacist not to take the clopidogrel since he will be having surgery and there is an increased risk of bleeding. The patient therefore did not take the much needed clopidogrel. Fortunately, during questioning by the nurse at the catheterization laboratory, the error was caught.
The patient’s angiogram showed significant mid left anterior descending artery plaque. He was therefore given a loading dose of clopidogrel and one drug-eluting stent was deployed.
The patient was discharged home later the same day without issue.
- When checking prescriptions for appropriateness, always consider the drug’s indication for use. The purpose of the medication would not only help in determining the appropriateness of the drug therapy and dosage, it can also help in preventing errors associated with look-alike and sound-alike drug names.
- If the purpose of the medication is not included on the prescription, ask the patient using open ended questions.
- Ensure that the patient receives appropriate patient counselling depending on the drug’s indication for use.
- If faced with ambiguous information during patient counselling, always contact the prescriber for clarification.
References:
- Plavix product monograph available at: http://products.sanofi.ca/en/plavix.pdf. Accessed April 10th, 2017.
- Francois Schiele, Nicolas Meneveau, and Jean-Pierre Bassand. Routine pre-treatment with clopidogrel before diagnostic coronary angiography: the question is right, but what about the answer? European Heart J 2008; 29:1475–1477
Please continue to send reports of medication errors in confidence to Ian Stewart at: [email protected] . Please ensure that all identifying information (e.g. patient name, pharmacy name, healthcare provider name, etc.) are removed before submitting.