Post-Myocardial Infarction

The post-myocardial infarction (post-MI) period begins once the acute presentation described in Acute Coronary Syndromes — STEMI or NSTEMI — has been stabilized, reperfused where appropriate, and the patient is being prepared for or has completed hospital discharge. The clinical task shifts from minutes-matter reperfusion to lifelong secondary prevention: several independent drug classes, layered together, each reduce the risk of a subsequent major adverse cardiovascular event (MACE) — reinfarction, stroke, or cardiovascular death — with additive rather than overlapping benefit, so a patient undertreated on any one pillar is measurably worse off.^[1] This chapter covers the pharmacotherapy, duration decisions, and monitoring that carry a post-MI patient from the day of discharge through the rest of their life, and assumes the acute-phase diagnosis and initial reperfusion/antithrombotic therapy in Acute Coronary Syndromes has already occurred.

A patient enters this chapter's scope the moment their index STEMI or NSTEMI has been diagnosed and acute management started — there is no separate diagnostic step for "post-MI" itself. What changes is the clinical task: instead of confirming the diagnosis, the pharmacist and prescriber are now tracking recovery, watching for early complications, and building the long-term drug regimen. Residual angina, new or worsening dyspnea, palpitations, and mood/sleep disturbance are all common in the weeks after MI, and each points toward a different problem — recurrent ischemia, evolving heart failure, arrhythmia, and depression, respectively — so a nonspecific "not feeling right" complaint after MI always deserves a specific follow-up question, not reassurance alone.

• Continued smoking after MI — the single highest-yield modifiable risk factor for recurrent events.
• Persistently elevated LDL-C, or nonadherence to prescribed lipid-lowering therapy.
• Uncontrolled hypertension.
• Diabetes mellitus, particularly with poor glycemic control.
• Obesity and sedentary lifestyle.
• Chronic kidney disease.
• Residual or progressive LV systolic dysfunction.
• Incomplete revascularization or extensive multivessel coronary disease.
• Depression, anxiety, and low social support — each independently associated with worse cardiovascular outcomes, not just quality of life.
• Early or unintentional discontinuation of dual antiplatelet therapy.
• Non-attendance at cardiac rehabilitation.

Follow-up history and examination

• At the first post-discharge visit (typically within 1-2 weeks), reconcile every discharge medication against what the patient is actually taking, and specifically confirm the P2Y12 inhibitor, its dose, and its planned stop date — early or unintentional DAPT discontinuation is one of the highest-yield things a community pharmacist can catch.
• Ask specifically about recurrent chest discomfort, exertional dyspnea, orthopnea, edema, palpitations, and any bleeding symptoms at every visit.
• Screen for depression and anxiety at baseline and periodically thereafter — both are common after MI and both independently worsen adherence and cardiovascular outcomes.
• Confirm cardiac rehabilitation referral was actually made, and ask whether the patient has started attending.
• Blood pressure, resting heart rate, weight, and waist circumference at each visit.

Investigations

• Fasting lipid panel 4-6 weeks after starting or changing lipid-lowering therapy, then at least annually once at target.
• Serum creatinine and potassium within 1-2 weeks of starting or up-titrating an ACE inhibitor, ARB, or mineralocorticoid receptor antagonist, then periodically once stable.
• Reassessment of left ventricular ejection fraction — at least 1 month post-MI in patients managed without revascularization, and at least 3 months post-MI in revascularized patients — to confirm LV recovery, guide continued mineralocorticoid receptor antagonist use, and determine whether a persistently reduced EF warrants implantable cardioverter-defibrillator referral.^[1]
• HbA1c in patients with diabetes, per the usual monitoring interval (see Diabetes Mellitus).

Risk stratification for extended dual antiplatelet therapy

The DAPT score is a published point-sum that estimates the ischemic-versus-bleeding tradeoff of continuing a P2Y12 inhibitor beyond 12 months; a score of 2 or higher favours benefit from continuation, while a score below 2 favours stopping.^[2]

The PRECISE-DAPT score is a separate, continuously-weighted tool — age, creatinine clearance, hemoglobin, white cell count, and prior spontaneous bleeding are all entered as continuous or graded values rather than a simple point-sum — that estimates out-of-hospital bleeding risk on DAPT. Because it is a regression-based score rather than an unambiguous point-sum, use a validated external calculator rather than manual scoring.

• LDL-C below 1.8 mmol/L (70 mg/dL) — or at least a 50% reduction from untreated baseline if that absolute target cannot be reached — on maximally tolerated lipid-lowering therapy.
• Blood pressure controlled to the target appropriate for the patient's comorbidities (see Hypertension).
• HbA1c below 7% in most patients with diabetes (see Diabetes Mellitus); avoid thiazolidinediones given their heart failure risk.
• Resting heart rate 50-60 bpm in patients on beta-blocker therapy.
• Complete smoking cessation.
• BMI 18.5-25 kg/m2 and waist circumference below 100 cm (men) or 90 cm (women), pursued through a sustained 5-10% weight reduction where indicated.
• Completion of a structured cardiac rehabilitation program.
• Full adherence to the prescribed dual antiplatelet therapy course for its entire planned duration.
• Annual influenza vaccination.
• Recognition and treatment of post-MI depression or anxiety where present.

• Refer every patient to a structured cardiac rehabilitation program before or shortly after discharge — an exercise-based, multidisciplinary program that reduces mortality and improves quality of life; referral should not be left to "if the patient asks."^[1]
• Prescribe an individualized aerobic and resistance exercise program once cleared — generally about 150 minutes of moderate-intensity aerobic activity per week (roughly 30-45 minutes, 3-5 times weekly) — adjusted for age, fitness level, and any residual LV dysfunction.
• Counsel on a Mediterranean-style or similarly cardioprotective dietary pattern, with specific attention to sodium restriction if hypertensive or with residual LV dysfunction.
• Offer intensive smoking cessation support (counselling plus pharmacotherapy) starting during the admission and reinforced at every subsequent visit — one of the highest-yield interventions available.
• Target sustained 5-10% weight loss where BMI or waist circumference exceed the treatment-target thresholds; nutritional counselling supports this.
• Screen for and address psychosocial issues — depression, anxiety, and reduced social support are all common after MI and all affect adherence and outcomes; offer cognitive behavioural therapy or refer for pharmacotherapy when indicated.
• Provide sublingual nitroglycerin with clear instructions for use in the setting of recurrent chest discomfort, and equally clear instructions on when that discomfort instead warrants calling emergency services.
• Offer annual influenza vaccination and ensure pneumococcal and other routine vaccinations are up to date.
• Counsel that resumption of sexual activity is generally safe once the patient can tolerate mild-to-moderate exertion (roughly climbing 2 flights of stairs) without symptoms, and that phosphodiesterase-5 inhibitors are contraindicated with nitrate use.
• Support medication adherence directly — blister packaging/dosette use, synchronized refills, and a specific pharmacist follow-up call in the first weeks after discharge all measurably reduce early nonadherence, which is highest for the P2Y12 inhibitor specifically.

Pregnancy

Most patients in this chapter are past the acute event, so the relevant pregnancy question is usually how to manage a patient with a prior MI who is pregnant or planning pregnancy, rather than a new peripartum MI (covered in Acute Coronary Syndromes). ACE inhibitors, ARBs, and statins are contraindicated in pregnancy and should be stopped before conception whenever feasible, with the indication reassessed and a pregnancy-appropriate alternative substituted where one exists. Low-dose ASA (81 mg/day) can be continued. If a P2Y12 inhibitor is still required, clopidogrel is preferred given more available safety experience than ticagrelor or prasugrel. If an oral anticoagulant is required (LV thrombus or atrial fibrillation), low molecular weight heparin is generally preferred over warfarin (teratogenic) or a DOAC (limited pregnancy safety data); this requires coordinated obstetric/cardiology/pharmacy management. Beta-blockers can generally be continued.

Breastfeeding

ASA and beta-blockers at usual secondary-prevention doses are considered compatible with breastfeeding. Clopidogrel, statins, and ACE inhibitors/ARBs have limited breastfeeding safety data — discuss the specific agent and clinical urgency with the treating team rather than assuming one answer applies to every drug in this chapter.

Pediatric

Not applicable — myocardial infarction is exceptionally rare in children and is managed individually by pediatric cardiology; the secondary-prevention framework, dosing, and evidence in this chapter are written for adults.

Renal impairment

Reduce or avoid mineralocorticoid receptor antagonists at eGFR <30 mL/min/1.73m2 given hyperkalemia risk. Reduce DOAC doses per each product's specific renal criteria (see Drug Tables) — apixaban, rivaroxaban, dabigatran, and edoxaban each have distinct rules. Avoid colchicine at eGFR <30 mL/min/1.73m2, and note reduced benefit in the pivotal trial at eGFR <60 mL/min/1.73m2.^[9] ACE inhibitor/ARB and eplerenone/spironolactone dosing all require closer potassium and creatinine monitoring as renal function declines.

Hepatic impairment

Use statins cautiously with active liver disease and monitor transaminases if clinically indicated. Warfarin requires closer INR monitoring given impaired synthesis of clotting factors. Most antiplatelet agents require no specific hepatic dose adjustment, but bleeding risk should be reassessed in significant hepatic dysfunction.

Older adults

Reduce prasugrel to 5 mg daily at age ≥75 (or favour ticagrelor/clopidogrel instead), and weigh bleeding risk carefully before any extended-DAPT decision. Start ACE inhibitor/ARB and beta-blocker titration at lower doses with more gradual up-titration. Reassess the overall regimen periodically for deprescribing opportunities as frailty, renal function, and bleeding risk evolve — polypharmacy itself is a modifiable risk factor for adverse events in this population.

Schedule the first follow-up visit within 1-2 weeks of discharge specifically to reconcile medications, confirm the P2Y12 inhibitor duration plan, and check for early adverse effects or affordability barriers to any of the pillar drug classes. Recheck fasting lipids 4-6 weeks after starting or changing lipid-lowering therapy, then at least annually. Recheck creatinine and potassium 1-2 weeks after starting or up-titrating an ACE inhibitor, ARB, or mineralocorticoid receptor antagonist, then periodically once stable, and again after any dose change or intercurrent illness causing volume depletion. Reassess LVEF at the guideline-specified interval (see Assessment & Diagnosis) to confirm recovery, guide continued mineralocorticoid receptor antagonist use, and determine ICD-referral timing. Confirm cardiac rehabilitation attendance and screen for depression/anxiety at follow-up visits, not only at discharge. At the 12-month mark specifically, revisit both the DAPT-duration decision and the beta-blocker-duration decision as distinct, deliberate checkpoints rather than allowing either to continue by inertia alone. Reinforce smoking-cessation status, home blood-pressure readings, and influenza vaccination at every visit.

1. Recurrent angina or objective ischemia despite an optimized regimen: confirm adherence first, then reassess for restenosis, a new lesion, or incomplete revascularization with repeat angiography.
2. LDL-C not at target despite high-intensity statin: confirm adherence and the actual dose taken, then add ezetimibe, then add a PCSK9 inhibitor (or inclisiran) if still above target — do not skip the ezetimibe step.
3. Suspected statin intolerance: before abandoning the statin class, try a lower dose, an alternate statin, or non-daily dosing; add ezetimibe, a PCSK9 inhibitor, or bempedoic acid if a meaningful statin dose still cannot be tolerated.
4. Blood pressure not at target on an ACE inhibitor/ARB plus beta-blocker: confirm adherence and sodium intake, then add a further agent per Hypertension rather than simply pushing the ACE inhibitor/ARB beyond its target dose.
5. Persistent smoking despite counselling: escalate to combination pharmacotherapy (varenicline plus nicotine replacement) and refer to an intensive cessation program.
6. Early or unexplained P2Y12 inhibitor nonadherence identified by the pharmacy: identify the specific cause (cost, side effect, misunderstanding) and contact the prescriber before any change — never stop or substitute a P2Y12 inhibitor unilaterally given the stent-thrombosis risk.
7. New atrial fibrillation diagnosed in a patient already on an antiplatelet regimen: transition to the dual-pathway (or, rarely, short triple-therapy) anticoagulation strategy in the Choose Initial Treatment algorithm, in consultation with cardiology.

• Allowing dual antiplatelet therapy to lapse — or letting a patient stop it — without confirming this was a deliberate, guideline-concordant plan; unplanned early discontinuation carries a real stent-thrombosis risk.
• Stopping a chronic beta-blocker in a preserved-EF patient unilaterally based on newer trial evidence without cardiology input — the evidence supports not routinely continuing indefinitely in this specific group, but interruption of an already-established beta-blocker has not itself been shown to be safe.
• Withholding or under-titrating an ACE inhibitor/ARB or beta-blocker for a modestly low but hemodynamically tolerated blood pressure or heart rate without attempting cautious up-titration first.
• Starting or up-titrating a mineralocorticoid receptor antagonist without checking baseline potassium/renal function, or without rechecking within about a week.
• Defaulting to triple therapy (ASA plus a P2Y12 inhibitor plus an oral anticoagulant) for a patient with atrial fibrillation and a recent PCI instead of the now-preferred dual-pathway approach.
• Missing colchicine's contraindications — significant renal impairment, active hepatic/biliary disease, or a strong CYP3A4/P-glycoprotein inhibitor — when considering it for residual inflammatory risk.
• Recommending a nonselective NSAID for musculoskeletal pain in a post-MI patient without considering atherothrombotic risk; if an NSAID is truly needed, naproxen carries the most favourable cardiovascular safety signal among the options studied.
• Skipping depression/anxiety screening — a common, undertreated post-MI complication that independently affects both adherence and cardiovascular outcomes.
• Not confirming a cardiac rehabilitation referral was actually made, or not following up on whether the patient attended.
• Assuming statin intolerance is a true class effect without first trying a lower dose, an alternate statin, or non-daily dosing.
• Skipping ezetimibe and jumping straight to a PCSK9 inhibitor, or conversely treating ezetimibe alone as sufficient when LDL-C remains well above target — the escalation is stepwise, not either/or.

How to use this table: Doses are adult doses and require patient-specific confirmation, including renal/hepatic adjustment. Select any drug name to open its complete Pharmasist Drug Database page.

Antiplatelet agents

Beta-blockers

Start within the first few days post-MI in all patients without contraindication (reactive airway disease, HR ≤50, 2nd-/3rd-degree heart block without pacemaker, SBP under 90-100 mmHg).

ACE inhibitors

Start within 24-48 hours of MI unless SBP under 100 mmHg; continue indefinitely, even with preserved LV function. Use lower initial doses if the patient is also on a diuretic.

Angiotensin receptor blockers

Use when ACE-inhibitor cough develops; do not combine an ACE inhibitor with an ARB.

Mineralocorticoid receptor antagonists

For patients already on an ACE inhibitor/ARB and beta-blocker who have LVEF ≤40% plus clinical heart failure or diabetes. Requires baseline potassium/renal function and reassessment 3 and 7 days after starting or titrating, then every 1-3 months once stable.

Lipid-lowering therapy

High-intensity statin for every post-MI patient regardless of baseline LDL-C, started before discharge; escalate stepwise if LDL-C remains ≥1.8 mmol/L (70 mg/dL).

Anti-inflammatory secondary prevention

Anticoagulation for atrial fibrillation or LV thrombus after MI

Dual-pathway therapy (a DOAC plus a single P2Y12 inhibitor) is now preferred over triple therapy for most patients with atrial fibrillation and recent PCI/ACS; triple therapy is reserved for especially high ischemic risk and only for the shortest effective period.

Smoking cessation pharmacotherapy

Safe to start during the post-MI admission; do not withhold on cardiovascular grounds.

Depression pharmacotherapy (when indicated)