What is the recommended management for angina pectoris using nitroglycerine?

Management of Angina Pectoris Using Nitroglycerin

Nitroglycerin is the cornerstone of angina management, with sublingual nitroglycerin recommended as first-line therapy for acute relief and prophylaxis, while various formulations can be used for long-term management with appropriate nitrate-free intervals to prevent tolerance. 1

Acute Angina Management

Sublingual Nitroglycerin

• Dosage: 0.3-0.4 mg every 5 minutes for up to 3 doses 1, 2
• Administration: Dissolve under tongue, do not swallow 2
• Timing: Take at first sign of anginal attack or 5-10 minutes before activities that might trigger angina 2
• Action: Onset within 1-5 minutes, duration 3-5 minutes 3
• Follow-up: If pain persists after 3 tablets in 15 minutes, seek immediate medical attention 2

Patient Instructions for Acute Episodes

1. Sit down when taking nitroglycerin to prevent falls from lightheadedness 2
2. For initial angina lasting more than 1 minute, take one sublingual dose 1
3. If angina does not subside within 3-5 minutes, call emergency services immediately 1
4. If pattern or severity of angina changes (more frequent, severe, or occurs at rest), contact healthcare provider without delay 1

Intravenous Nitroglycerin (Hospital Setting)

Indications: For patients with:

• Symptoms not relieved by sublingual nitroglycerin 1
• Heart failure 1
• Hypertension 1
• Refractory or recurrent ischemia 1

Dosing Protocol:

• Initial dose: 5-10 μg/min 3
• Titration: Increase by 5-10 μg/min every 3-5 minutes 3
• Maximum dose: Generally 200 μg/min to avoid excessive hypotension 3
• Monitor blood pressure at 5 minutes post-administration (maximum BP reduction point) 3

Long-term Angina Management

Transdermal Nitroglycerin

• Dosage: 0.2-0.8 mg/hour 1
• Duration: Apply for 12-14 hours daily with a 10-12 hour nitrate-free interval (typically overnight) 3, 4
• Rationale: Intermittent therapy prevents tolerance development 4

Oral Nitrates

• Isosorbide dinitrate: 5-80 mg, 2-3 times daily 1
• Isosorbide mononitrate: 20 mg twice daily or 60-240 mg once daily (extended-release) 1
• Schedule: Ensure a daily nitrate-free interval of 10-12 hours 3

Contraindications and Precautions

Absolute Contraindications:

• Systolic blood pressure <90 mmHg or ≥30 mmHg below baseline 3
• Recent use of phosphodiesterase-5 inhibitors:
  • Within 24 hours of sildenafil/vardenafil 3
  • Within 48 hours of tadalafil 3
• Right ventricular infarction 3
• Severe aortic stenosis 3

Use with Caution in:

• Patients who may be volume-depleted 2
• Hypertrophic cardiomyopathy (may worsen angina) 2
• Severe bradycardia (<50 bpm) or tachycardia (>100 bpm) 3

Adverse Effects Management

Common Side Effects:

• Headache: Often a marker of drug activity; may decrease with continued use 2
• Hypotension: More common with higher doses (>200 μg/min) 3
• Lightheadedness: Particularly upon standing; advise patients to sit when taking 2
• Reflex tachycardia: Can be minimized by concurrent beta-blocker use 3

Tolerance Management:

• Ensure nitrate-free interval of 10-12 hours daily 3
• Avoid continuous 24-hour administration 4
• For sublingual use, tolerance is unlikely unless used very frequently (scores of tablets daily) 2

Combination Therapy

• Beta-blockers: Work synergistically with nitrates by preventing reflex tachycardia 3
• Calcium channel blockers: Can be combined with nitrates for enhanced effect 3
• All patients post-NSTE-ACS: Should be given sublingual/spray nitroglycerin with verbal and written instructions for use 1

Storage and Handling

• Keep nitroglycerin in original glass container 2
• Tightly cap after each use to prevent loss of potency 2
• Burning/tingling sensation when administered sublingually is common but not a reliable indicator of potency 2

By following this structured approach to nitroglycerin administration, clinicians can effectively manage angina pectoris while minimizing adverse effects and preventing tolerance development.