Page 549 - Cardiac Nursing

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C HAPTER 22 / Acute Coronary Syndromes 525
plan for chronic pain should be instituted as soon as possible and binding to its receptor and prevent activation of the GP IIb/IIIa
81
would begin with acetaminophen or aspirin, small doses of nar- complex needed for platelet aggregation. Two oral ADP receptor
cotics, or nonacetylated salicylates. If pain relief is inadequate, a antagonists currently used for ACS and PCI include clopidogrel
nonselective, nonsteroidal anti-inflammatory drug, such as and ticlopidine. Clopidogrel and ticlopidine irreversibly modify
naproxen, is a possible alternative. 3 the platelet ADP receptor for the life of the platelet. Dose-
dependent inhibition of the platelet is seen after 2 hours of a sin-
Angiotensin Converting Enzyme Inhibitors gle dose. Clopidogrel is the primary chosen ADP receptor antag-
onist and preferred to ticlopidine because of more rapid inhibition
Actions/Indications. ACEIs block the conversion of an-
of platelets, once-a-day dosing, and a favorable safety profile that
giotensin I to angiotensin II, a potent vasoconstrictor. The use of
is comparable to aspirin. 83 A loading dose for clopidogrel is 300
this class of drugs has been shown to reduce mortality rates in pa-
to 600 mg and recommended in ACS and PCI with stenting for
tients with STEMI, NSTEMI with LV systolic dysfunction, dia- 53
4
betes mellitus with LV dysfunction, and severe CAD. Angiotensin rapid platelet inhibition. Inhibition reaches a steady state after 3
to 7 days. Platelet aggregation and bleeding time gradually returns
receptor blockers (ARBs) may be used in patients intolerant to
to normal after 5 days of drug cessation. 81
ACEI.
Contraindications/Adverse Reactions. ACEI should be Contraindications/Adverse Reactions. Contraindications
used cautiously in patients who are hemodynamically unstable, include known hypersensitivity to the drug or any drug compo-
particularly in the presence of extracellular fluid deficit, because the nents, or any active bleeding. Serious adverse effects include
vasodilatation caused with ACEI therapy can produce marked hy- neutropenia, thrombotic thrombocytopenic purpura, and gas-
84
potension. ACEI are used cautiously in patient with renal insuffi- trointestinal or cerebral hemorrhage. Other adverse effects in-
ciency, necessitating close surveillance of renal function. ACEIs are clude gastrointestinal problems (diarrhea, abdominal pain, nausea,
contraindicated in patients with bilateral renal artery stenosis. vomiting) and rash.
Nursing Implications. Patients who have received a stent
Nursing Implications. Before initiation of ACEI therapy,
with primary PCI must understand the importance and necessity
baseline BP measurement and serum creatinine level should be
of continued daily use of clopidogrel (or ticlopidine if allergic to
obtained. Monitor the patient for hypotension after initiation of
clopidogrel) for a specified duration as prescribed. Acute stent clo-
therapy, and know the parameters for holding or stopping med-
sure and the potential for MI or death have been reported with
ication. Serum creatinine levels are monitored closely; a signifi-
premature cessation of clopidogrel or ticlopidine.
cant elevation or trend in elevation is reported promptly so that
Patients taking ticlopidine must be aware of the need to mon-
discontinuation of therapy can be considered by the provider.
itor complete blood cell count with differential every 2 weeks for
Antiplatelet Agents the first 3 months of therapy to screen for neutropenia. Patients
should be told that it might take them longer than usual to stop
A combination of aspirin (acetylsalicylic acid or ASA), an antico- bleeding when they are taking clopidogrel or ticlopidine, and that
agulant, and antiplatelet therapy represent the most effective ther- they should report unusual bleeding. Patients should advise their
apy for ACS. physicians and dentists that they are taking clopidogrel or ticlopi-
dine before a surgery is scheduled; patients should not stop taking
Aspirin the medication unless advised by their cardiologist.
Actions/Indications. ASA inhibits COX-1 within platelets, IV Antiplatelet Agents
which prevents the formation of thromboxane A2, diminishing the
platelet aggregation promoted by this pathway. Patients who have ACC/AHA Guidelines for Antiplatelet Therapy Recom-
not taken aspirin before presentation with STEMI should chew sol- mendations. 4 These guidelines are followed by sections on
uble aspirin 162 to 325 mg. Although some trials have used enteric- antiplatelet actions/indications, contraindications/adverse reac-
coated aspirin for initial dosing, more rapid buccal absorption occurs tions, and nursing implications.
2
with non-enteric-coated aspirin formulations. Aspirin is continued 1. Aspirin should be administered to UA/NSTEMI patients as
indefinitely in patients with CAD unless contraindicated.
soon as possible after hospital presentation and continued in-
Contraindications/Adverse Reactions. Aspirin is con- definitely in patients not known to be intolerant of that med-
traindicated for patients with a known sensitivity to the drug. Pa- ication. (Class I, level of evidence: A)
tients with a history of gastrointestinal bleeding should use ASA 2. Clopidogrel (loading dose followed by a maintenance dose)
with caution, take enteric-coated aspirin, and have supplemental should be administered to UA/NSTEMI patients who are un-
therapy to prevent recurrence of bleeding. able to take ASA because of hypersensitivity or major gastroin-
testinal intolerance. (Class I, level of evidence: A) In
Nursing Implications. Aspirin should be taken with meals UA/NSTEMI patients with a history of gastrointestinal bleed-
to avoid gastric irritation. Teach patients to monitor for possible ing, when ASA and clopidogrel are administered alone or in
bleeding or allergic reaction. Periodic hemoglobin and hematocrit combination, drugs to minimize the risk of recurrent gastroin-
levels should be monitored.
testinal bleeding (proton-pump inhibitors) should be pre-
Adenosine Diphosphate Receptor scribed concomitantly. (Class I, level of evidence: B)
Antagonists 3. For UA/NSTEMI patients in whom an initial invasive strategy
is selected, antiplatelet therapy in addition to ASA should be
Actions/Indications. The adenosine diphosphate (ADP) re- initiated before diagnostic angiography and either clopidogrel
ceptor antagonists are agents that selectively inhibiting ADP or an IV GP IIb/IIIa inhibitor. (Class I, level of evidence: A)