What is the dosage and duration of antianginal medications, such as beta-blockers (e.g. bisoprolol) or calcium channel blockers (e.g. amlodipine), for a patient with chronic stable angina?

Antianginal Medication Dosing and Duration

For chronic stable angina, beta-blockers should be initiated as first-line therapy at the following doses: bisoprolol 10 mg once daily, metoprolol 50-200 mg twice daily, or atenolol 50-200 mg once daily, and these medications are typically continued indefinitely as long-term maintenance therapy unless contraindications develop. 1

Beta-Blocker Dosing

Specific Beta-Blocker Regimens

Beta-1 selective agents are preferred due to fewer side effects compared to non-selective agents. 1

• Bisoprolol: 10 mg once daily 1
• Metoprolol: 50-200 mg twice daily (immediate release) or metoprolol CR 200 mg once daily for 24-hour coverage 1, 2
• Atenolol: 50-200 mg once daily (or 50 mg twice daily) 1
• Propranolol: 20-80 mg twice daily 1
• Nadolol: 40-80 mg once daily 1
• Carvedilol: Start 6.25 mg twice daily, uptitrate to maximum 25 mg twice daily 1

Target Heart Rate

The goal is to achieve a resting heart rate of 50-60 beats per minute, which can be assessed through exercise testing to ensure adequate beta-blockade. 1, 2, 3

Initiation Timing

For unstable angina/NSTEMI, oral beta-blockers should be initiated within the first 24 hours in hemodynamically stable patients without contraindications. 1, 2 Intravenous beta-blockers should be avoided in hemodynamically unstable patients due to increased risk of cardiogenic shock. 1, 2

Calcium Channel Blocker Dosing

When beta-blockers are contraindicated, not tolerated, or symptoms persist, calcium channel blockers are the alternative first-line option. 1, 3

Dihydropyridine Calcium Channel Blockers

• Amlodipine: 5-10 mg once daily (long duration of action) 1, 4
• Nifedipine slow-release: 30-180 mg once daily 1
• Felodipine: 5-10 mg once daily 1
• Nicardipine: 20-40 mg three times daily 1

Non-Dihydropyridine Calcium Channel Blockers

• Diltiazem slow-release: 120-360 mg once daily 1
• Verapamil slow-release: 120-480 mg once daily 1

Immediate-release nifedipine is not recommended for unstable angina/NSTEMI except with concomitant beta-blockade. 1

Combination Therapy Strategy

If symptoms persist on monotherapy, the combination of a beta-blocker with a dihydropyridine calcium channel blocker (such as amlodipine) should be considered. 1, 3

Do not combine non-dihydropyridine calcium channel blockers (verapamil or diltiazem) with beta-blockers in patients with heart failure due to negative inotropic effects and risk of conduction disturbances. 1, 3

Second-Line Antianginal Agents

When two first-line agents fail to control symptoms, add one of the following:

• Long-acting nitrates: Dosing varies by formulation but requires a nitrate-free interval to avoid tolerance 1, 3
• Ranolazine: Particularly effective for microvascular angina 1, 3
• Nicorandil: 20 mg twice daily 1
• Trimetazidine: Add-on therapy when symptoms persist 1
• Ivabradine: Only for patients with left ventricular systolic dysfunction (LVEF <40%) and inadequate symptom control 1

Ivabradine is not recommended for patients with LVEF >40% and no clinical heart failure. 1

Duration of Therapy

Antianginal medications are typically continued indefinitely as chronic maintenance therapy for patients with chronic stable angina. 1, 3 The duration is not time-limited but rather continues as long as:

• The patient has ongoing coronary artery disease
• Symptoms require control
• No contraindications develop
• The medication is well-tolerated

For post-myocardial infarction patients, beta-blockers are strongly recommended for secondary prevention and should be continued long-term. 1

Special Consideration for Beta-Blocker Discontinuation

If beta-blocker discontinuation becomes necessary, taper gradually over 1-2 weeks by reducing the dose by 25-50% every 3-7 days to avoid rebound hypertension, tachycardia, and worsening angina. 5, 2 For bisoprolol and nadolol with longer half-lives, use a more gradual taper with dose adjustments at 5-7 day intervals. 5

Critical Contraindications to Beta-Blockers

Do not initiate beta-blockers in patients with:

• Heart failure with decompensation (rales or S3 gallop) 1, 2
• Hypotension (systolic BP <90 mmHg) 1, 2
• Significant bradycardia (heart rate <50 bpm) 1, 2
• Marked first-degree AV block (PR interval >0.24 seconds) or any second- or third-degree AV block without a functioning pacemaker 1, 2
• Active asthma or severe reactive airway disease 1, 2

For patients with mild COPD or mild wheezing, use low-dose beta-1 selective agents (such as metoprolol) cautiously rather than complete avoidance. 1, 2

Short-Acting Nitrates

Short-acting nitrates (sublingual nitroglycerin) are recommended for all patients for immediate symptom relief and situational prophylaxis, taken as needed for acute angina episodes. 1, 3 These are not scheduled medications but rather used on-demand.

Monitoring During Treatment

Monitor heart rate and blood pressure at each dose adjustment, and assess exercise tolerance and angina frequency during oral therapy. 2 An angina attack that does not respond to short-acting nitroglycerin should be regarded as a possible myocardial infarction. 3