Reference — Cardiac

ACS Medications Reference

Quick reference for medications used in acute coronary syndrome — mechanism, indication, key contraindications, and nursing considerations for aspirin, nitroglycerin, morphine, heparin, P2Y12 inhibitors, beta-blockers, and statins.

Educational use only. All ACS medications require provider orders and clinical context. Dosing and contraindications vary by patient and institution. This reference supports learning and NCLEX preparation. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.

Aspirin

Antiplatelet

Mechanism: Irreversibly inhibits COX-1 → reduces thromboxane A₂ → inhibits platelet aggregation

ACS Indication: All ACS types — first-line antiplatelet therapy; given immediately at onset of suspected ACS

Typical ACS Dose: 325 mg non-enteric coated, chewed (faster absorption)

Key Contraindications:

!Active major bleeding
!True aspirin allergy (rare — consider clopidogrel monotherapy)
!Severe thrombocytopenia

Nursing Considerations:

›Give immediately — first medication in ACS protocol
›Non-enteric coated and chewed — faster buccal absorption than swallowed
›Continue indefinitely post-MI; dual antiplatelet therapy added (DAPT)
›Monitor for GI bleeding with long-term use

Nitroglycerin (NTG)

Nitrate / Vasodilator

Mechanism: Converts to nitric oxide → venodilation → reduced preload → decreased myocardial oxygen demand; mild coronary vasodilation

ACS Indication: Ongoing chest pain in ACS; acute hypertension; acute pulmonary edema

Typical ACS Dose: SL 0.4 mg q5 min × 3 doses; IV infusion for refractory pain or HTN

Key Contraindications:

!SBP <90 mmHg or HR <50 or >100
!Right ventricular (RV) infarction — avoid (preload-dependent RV needs volume)
!PDE-5 inhibitor use within 24 hr (sildenafil, vardenafil) or 48 hr (tadalafil) — severe hypotension risk
!HCM with outflow obstruction

Nursing Considerations:

›Check BP before each dose — hold if SBP <90
›RV infarct: always obtain right-sided ECG for inferior STEMI before giving NTG
›Headache is common (vasodilation) — not a reason to withhold
›IV NTG: non-PVC tubing required (NTG absorbs into PVC), protect from light

Morphine

Opioid Analgesic

Mechanism: Opioid receptor agonist → analgesia + anxiolysis; mild venodilation

ACS Indication: Refractory ACS chest pain unresponsive to nitroglycerin (use with caution — evidence now suggests possible harm in NSTEMI)

Typical ACS Dose: 2–4 mg IV q5–15 min as needed

Key Contraindications:

!Hemodynamic instability
!Respiratory depression or altered mental status
!Use caution in NSTEMI — registry data suggests association with increased mortality (delays clopidogrel absorption, more adverse events)

Nursing Considerations:

›Morphine is no longer first-line in NSTEMI — NTG and other measures preferred
›Monitor respiratory rate, SpO₂, and BP closely after administration
›Have naloxone available
›Document pain response after administration
›Current AHA/ACC guidelines: use morphine in STEMI if pain is refractory to NTG; use cautiously in NSTEMI

Heparin (UFH / Unfractionated Heparin)

Anticoagulant

Mechanism: Activates antithrombin III → inhibits thrombin (IIa) and Factor Xa → prevents thrombus extension and new clot formation

ACS Indication: ACS anticoagulation during hospitalization; weight-based IV infusion for STEMI/NSTEMI; procedural anticoagulation during PCI

Typical ACS Dose: Weight-based IV: 60 units/kg bolus (max 4000 u) + 12 units/kg/hr infusion. Titrate per aPTT or anti-Xa protocol

Key Contraindications:

!Active major bleeding
!HIT (Heparin-Induced Thrombocytopenia) — switch to bivalirudin or argatroban
!Recent major surgery (relative)

Nursing Considerations:

›Monitor aPTT every 6 hours; adjust per protocol — target aPTT 60–100 seconds
›Check platelets every 2 days for HIT (4Ts score)
›Reversal agent: protamine sulfate
›Monitor for bleeding: IV sites, hematuria, guaiac stools, neuro changes
›LMWH (enoxaparin) often used in NSTEMI for subcutaneous administration instead of IV UFH

P2Y12 Inhibitors (Clopidogrel, Ticagrelor, Prasugrel)

Antiplatelet (ADP receptor blocker)

Mechanism: Block P2Y12 ADP receptor on platelets → inhibit platelet activation and aggregation; used with aspirin as dual antiplatelet therapy (DAPT)

ACS Indication: All ACS types — initiated with aspirin as DAPT; continued after PCI with stent placement (DAPT 6–12 months minimum)

Typical ACS Dose: Clopidogrel: 300–600 mg loading → 75 mg daily. Ticagrelor: 180 mg loading → 90 mg BID. Prasugrel: 60 mg loading → 10 mg daily (avoid if >75 yr, <60 kg, prior stroke/TIA)

Key Contraindications:

!Active pathological bleeding
!Prasugrel: prior stroke or TIA (absolute), age >75 or weight <60 kg (relative)
!Ticagrelor: severe hepatic impairment
!Clopidogrel: CYP2C19 poor metabolizers may have reduced efficacy

Nursing Considerations:

›Loading dose timing varies — check provider order and catheterization lab timing
›Bleeding is the primary risk — monitor closely
›Hold ticagrelor/clopidogrel 5–7 days before elective CABG if planned
›Ticagrelor causes dyspnea (non-bronchospastic, mechanism unclear) — common side effect that does not require discontinuation in most patients
›Patient education: do not stop DAPT without provider guidance — stent thrombosis risk

Beta-Blockers

Beta-1 Adrenergic Antagonist

Mechanism: Block beta-1 receptors → reduce HR, contractility, and myocardial oxygen demand; anti-ischemic and antiarrhythmic

ACS Indication: ACS — reduce ischemia, prevent ventricular arrhythmias, reduce remodeling post-MI; initiated within 24 hours if hemodynamically stable

Typical ACS Dose: Metoprolol tartrate: 25–50 mg oral BID; IV metoprolol 5 mg × 3 doses in acute setting (rarely used); Carvedilol for HF post-MI

Key Contraindications:

!Hemodynamic instability: hypotension (SBP <90), bradycardia (HR <50)
!Acute decompensated heart failure / cardiogenic shock
!Severe bronchospasm (relative — cardioselective preferred)
!High-degree AV block without pacemaker

Nursing Considerations:

›Check HR and BP before each dose — hold if HR <50 or SBP <90 (per order)
›Do not give IV beta-blockers in cardiogenic shock or decompensated HF
›Monitor for bronchospasm in COPD/asthma patients — use cardioselective agents
›Gradual dose titration post-MI; do not abruptly discontinue (rebound tachycardia/ischemia)

Statins (High-Intensity)

HMG-CoA Reductase Inhibitor

Mechanism: Inhibit hepatic cholesterol synthesis → lower LDL-C; pleiotropic effects: anti-inflammatory, plaque-stabilizing, endothelial-protective

ACS Indication: All ACS — high-intensity statin initiated early regardless of baseline LDL; reduces cardiovascular mortality and plaque vulnerability

Typical ACS Dose: Atorvastatin 80 mg/day or Rosuvastatin 40 mg/day — high-intensity dosing initiated within 24–48 hours

Key Contraindications:

!Active liver disease or significantly elevated transaminases
!Pregnancy and breastfeeding
!Concurrent use of strong CYP3A4 inhibitors (clarithromycin, some antifungals) with certain statins — increased myopathy risk

Nursing Considerations:

›Statins are started early post-ACS — significant mortality benefit even with normal LDL
›Monitor LFTs — baseline before initiation; check again if symptoms suggest liver toxicity
›Myopathy: monitor for muscle pain, weakness, dark urine (rhabdomyolysis — rare but serious)
›Statin should be continued indefinitely post-ACS — long-term secondary prevention

NCLEX Pearls

›Aspirin 325 mg chewed (non-enteric coated) is the first medication given for suspected ACS.
›Nitroglycerin is CONTRAINDICATED in inferior STEMI with RV involvement — check right-sided ECG first.
›Hold nitroglycerin if SBP <90 mmHg or if patient used a PDE-5 inhibitor within 24–48 hours.
›Morphine use in NSTEMI is now cautioned — evidence suggests possible harm; reserve for refractory pain.
›Monitor platelets every 2 days on heparin for HIT (4Ts score) — thrombocytopenia + thrombosis = HIT.
›Beta-blockers are contraindicated in cardiogenic shock and acute decompensated HF — hold if SBP <90 or HR <50.
›High-intensity statins (atorvastatin 80 mg) are started early post-ACS regardless of baseline LDL levels.

Related Resources

Acute Coronary Syndrome (ACS) GuideACS overview, pathophysiology, clinical presentation, and nursing priorities

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STEMI vs NSTEMI GuideECG differences, treatment priorities, and nursing implications

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Cardiac Medications ReferenceAdenosine, amiodarone, atropine, dopamine, epinephrine — ACLS cardiac drugs

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Anticoagulant Comparison ReferenceHeparin, enoxaparin, warfarin, DOACs — monitoring, reversal, nursing considerations

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Standards & sources

Fact-checked Jun 20, 2026

This page is written to align with American Heart Association (AHA) · American College of Cardiology (ACC) · AHA ACLS Guidelines. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →