Introduction to CV Pharmacology - Orlando Health

CV Pharmacology
who are unable to take clopidrogrel or aspirin, or for those in whom other agents have been
ineffective.
Indications
Platelet aggregation inhibitors are used to reduce the risk of thrombotic events such as
myocardial infarction and stroke in patients with previously diagnosed atherosclerotic vascular
disease. They are also used with patients with acute coronary syndromes who are undergoing
PCI.
When a GPIIb/IIIa inhibitor is used, aspirin and/or clopidogrel become part of the standard
adjunct therapy, along with heparin or enoxaparin (Lovenox). The clinical indications for aspirin
and clopidogrel continue to expand because platelets play such an important role in all types of
vascular disease. For example, numerous studies have proven the efficacy with acute onset MI,
stable and unstable angina, cath lab procedures, and non-hemorrhagic strokes.
Precautions and Interactions
Platelet aggregation inhibitors should not be used in any patients with active pathological
bleeding such as peptic ulcer or intracranial hemorrhage. They are to be used with caution in
patients who are at risk of increased bleeding due to impaired liver function, trauma or surgery.
They should also be discontinued 7-14 days prior to elective surgery. Furthermore, drugs such as
aspirin, heparin, warfarin, and NSAIDs that may interfere with hemostasis, are administered with
extreme caution to patients taking ticlopidine or clopidrogrel.
Adverse reactions include rash, nausea, vomiting, diarrhea, constipation, and abdominal pain.
These reactions have resulted in discontinuing the drug in approximately 3% of patients taking
clopidrogrel and 21% of patients taking ticlopidine. Blood dyscrasias as previously listed, may
occur with either of these agents; the incidence is approximately 1 out of every 2000-4000
patients taking ticlopidine and approximately 1 out of every 250,000 of those taking
clopidrogrel. Because of its increased risk for adverse reactions, ticlopidine is rarely used & is
usually given to patients unable to take other agents or in those for whom other agents are
ineffective.
In addition to the bleeding precautions for aspirin, there may also be some notable GI distress or
bleeding. In such cases an enteric coated aspirin preparation may be suitable.
© 2010 Orlando Health, Education & Development 47