When is nitroglycerin indicated?

Nitroglycerin Indications in Clinical Practice

Nitroglycerin is primarily indicated for the acute relief of angina pectoris, management of ongoing ischemic discomfort, control of hypertension, and management of pulmonary congestion in acute coronary syndromes. 1, 2

Primary Indications for Sublingual Nitroglycerin

• Acute relief of an angina attack 1
• Acute prophylaxis of angina pectoris due to coronary artery disease 1
• Management of ongoing ischemic discomfort in acute coronary syndromes 2
  • Administer up to 3 doses of sublingual nitroglycerin (0.3-0.4 mg) at 5-minute intervals 2, 3
  • Monitor blood pressure after each dose 3

Primary Indications for Intravenous Nitroglycerin

• Treatment of persistent anginal pain after oral nitrate therapy 2, 4
• Control of congestive heart failure in the setting of acute myocardial infarction 4
• Management of hypertension in acute coronary syndromes 2, 4
• Management of pulmonary congestion 2, 4
• Perioperative hypertension management 4
• Induction of intraoperative hypotension 4

Dosing Recommendations

Sublingual Nitroglycerin

• Initial dose: 0.3-0.4 mg every 5 minutes up to 3 doses 2
• Patient should be seated during administration to prevent falls 3
• Evaluate need for IV nitroglycerin after 3 doses if symptoms persist 2

Intravenous Nitroglycerin

• Starting dose: 10 μg/min 2
• Titration: Increase by 5-10 μg/min every 5-10 minutes 2
• Target: Relief of symptoms and hemodynamic tolerability 2
• Consider alternative therapy if doses >200 μg/min are required 2

Absolute Contraindications

• Hypotension (SBP <90 mmHg or ≥30 mmHg below baseline) 2, 3
• Extreme bradycardia (<50 bpm) 2, 3
• Tachycardia (>100 bpm) in the absence of heart failure 2, 3
• Right ventricular infarction 2, 3
• Recent use of phosphodiesterase-5 inhibitors 2, 3:
  • Within 12 hours of avanafil 2
  • Within 24 hours of sildenafil/vardenafil 2, 3
  • Within 48 hours of tadalafil 2, 3

Special Considerations

Before Administration

• Check vital signs, particularly blood pressure and heart rate 3
• Obtain a 12-lead ECG to identify location of infarct 3
• Establish IV access, especially in patients with inferior MI 3
• Screen for recent use of medications for erectile dysfunction 3

During Administration

• Monitor blood pressure after each dose 3
• Discontinue if systolic BP drops below 90 mmHg or 30 mmHg below baseline 3
• Be vigilant for development of tolerance with prolonged use 5, 6

Cautions

• Use extreme caution in patients with suspected right ventricular involvement 3
• Be aware of potential for uneven absorption with topical formulations 2, 3
• Consider volume status before administration, as hypovolemia can exacerbate hypotension 3

Clinical Pearls

• Nitroglycerin primarily causes venodilation at low doses and arterial dilation at higher doses 3
• Tolerance develops with continuous or frequent daily use of long-acting nitrate preparations 5, 6
• Transdermal nitroglycerin patches may not provide antianginal effects for a full 24 hours due to tolerance 7
• Buccal nitroglycerin can be an alternative to IV nitroglycerin in unstable angina with potentially fewer adverse effects 8

By following these guidelines for nitroglycerin administration, clinicians can effectively manage angina and other cardiac conditions while minimizing adverse effects and optimizing patient outcomes.