Medications Medications

Most pharmacological evidence to support choice of treatment is based on trials from patients with STEMI, so applying this evidence to NSTEMI patients, although often done, requires some caution.

Table 1: Antithrombotic medications used to treat STEMI and NSTEMI

Acute Prophylaxis or prevention Comments
Aspirin 300mg (chewed or soluble) Aspirin 100-150mg daily Lower doses (e.g.,75mg daily) for prevention of CVD are used in some countries. This is acceptable and supported by the literature.

Clopidogrel 300-600mg

Ticagrelor 180mg or

Prasugrel 60mg immediately

(All taken orally)

Clopidogrel 75mg daily or

Ticagrelor 90mg bd or

Prasugrel 10mg daily (5mg if age >75y)
The 600mg dose of clopidogrel may have a faster onset of action compared with the 300mg dose and may be more appropriate for patients with a short time period between loading dose and PCI.
Unfractionated heparin or low-molecular-weight heparin such as enoxaparin 1mg/kg sc bd   For STEMI and high-risk NSTEMI only. Reduce enoxaparin dose in renal impairment.
+/- Thrombolysis   For STEMI only
See National Heart Foundation of Australia ACS treatment algorithm.
  Glycoprotein IIb/IIIa inhibitors e.g., IV abciximab May be used only in high-risk NSTEMI patients undergoing PCI.

bd = twice daily

Table 2: Other first-line medications used to treat STEMI and NSTEMI

Class Acute Prophylaxis or prevention Comments
Nitrates GTN (sublingual tablets/spray) stat (immediate) dose and repeated as needed. GTN (sublingual tablets/spray). For all patients post STEMI or NSTEMI.
Statins E.g., Atorvastatin 80mg daily given immediately. Atorvastatin 40mg-80mg daily initially after ACS.

Atorvastatin is often preferred as it is a potent statin with most evidence for use in the acute phase of ACS.

Ideally, statins should be started before PCI.

Rosuvastatin, a potent statin, currently has no evidence in secondary prevention of MI but many cardiologists presume a class effect.
Beta-blocker E.g.,Metoprolol 25mg- 50mg bd. Titrate to optimal tolerated dose. Atenolol or metoprolol should be used unless the patient has significant left ventricular impairment (LVEF <40%), in which case bisoprolol, carvedilol or metoprolol SR have a better evidence base.
ACE inhibitors   ACE inhibitor (especially in LVEF <40%). For patients post-MI with preserved LVEF, it is less clear whether ACE inhibitors should be used. 
MRAs     For patients with LVEF <40% post-MI.
Nicotine Nicotine replacement therapy. Nicotine replacement therapy.

Offer to all smokers.

Varenicline increases MI risk slightly. Make an individual risk-benefit analysis before prescribing varenicline to patients at high MI risk.

 See Smoking cessation algorithm.

Dual antiplatelet therapy (DAPT) is essential before and after PCI. All patients should be loaded with aspirin and either clopidogrel, prasugrel or ticagrelor. Patients who are currently taking these medicines should be reloaded before PCI, in case adherence has been suboptimal.

Statins should ideally be started before PCI, due to their beneficial pleiotropic effects. Reduced thrombosis risk in the short term has been demonstrated when statins are used before PCI compared with commencing them after PCI.

DAPT is usually used for up to 12 months. Actual duration is often determined by the patient's bleeding and thrombotic risk and the type of coronary stent deployed. Drug eluting stents (DES) take longer to endothelialise (i.e., be incorporated into the artery wall) than a bare metal stent (BMS). Most guidelines suggest DAPT for 12 months for patients with a DES, and a minimum of 4-6 weeks for those with a BMS. However, those with a BMS and a low risk of bleeding often receive the full 12 months of DAPT. Patients who are managed medically without PCI usually remain on DAPT for 12 months. Older age and tobacco use increase the risk of bleeding.[#levine-gn-bates-er-blankenship-jc-et-al.-2011] Those who have previously had a thrombotic event after PCI may remain on DAPT for more than 12 months or indefinitely.

Avoid glycoprotein IIb/IIIa receptor antagonists where possible, except for high-risk NSTEMI. Some evidence supports tirofiban in patients with NSTEMI awaiting PCI and abciximab use in patients during PCI. However, the trials supporting this generally were conducted prior to dual antiplatelet use; PCI/stent technology has developed to such an extent that outcomes from earlier treatment trials may no longer be relevant.

The evidence base for long-term management of unstable angina is weaker than that for STEMI and NSTEMI. Recommended preventative therapy incorporates low-dose aspirin and statins as first-line treatment.

  • Levine GN, Bates ER, Blankenship JC, et al. ACCF/AHA/SCAI guideline for percutaneous coronary intervention: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. J Am Coll Cardiol 2011;58:e44–122.