Concerns related to adverse effects:
• Headache: Dose-related headaches may occur, especially during initial dosing.
• Hypotension/bradycardia: Severe hypotension and shock may occur (even with small doses); paradoxical bradycardia and increased angina pectoris may accompany hypotension. Orthostatic hypotension may also occur; ethanol may accentuate this. Use with caution in volume depletion, preexisting hypotension, constrictive pericarditis, aortic or mitral stenosis, and extreme caution with inferior wall myocardial infarction (MI) and suspected right ventricular involvement. According to the American College of Cardiology Foundation/American Heart Association, avoid use in patients with severe hypotension (SBP <90 mm Hg or >30 mm Hg below baseline), marked bradycardia or tachycardia, and right ventricular MI (ACCF/AHA [O'Gara 2013]).
• Increased intracranial pressure: Nitroglycerin may precipitate or aggravate increased intracranial pressure and subsequently may worsen clinical outcomes in patients with neurologic injury (eg, intracranial hemorrhage, traumatic brain injury) (Rangel-Castilla 2008). Use is contraindicated in patients with increased intracranial pressure.
Disease-related concerns:
• Hypertrophic cardiomyopathy: Avoid use in patients with hypertrophic cardiomyopathy with outflow tract obstruction; nitrates may reduce preload, exacerbating obstruction and cause hypotension or syncope and/or worsening of heart failure (HF) (ACCF/AHA [Gersh 2011]).
Dosage form specific issues:
• Intra-anal ointment: Use caution when treating rectal anal fissures with nitroglycerin in patients with suspected or known significant cardiovascular disorders (eg, cardiomyopathies, HF, acute MI); intra-anal nitroglycerin administration may decrease systolic BP and decrease arterial vascular resistance.
• Long-acting agents: Avoid use of long-acting agents in acute MI or acute HF; cannot easily reverse effects if adverse events develop.
• Propylene glycol: Some dosage forms may contain propylene glycol; large amounts are potentially toxic and have been associated hyperosmolality, lactic acidosis, seizures, and respiratory depression; use caution (AAP 1997; Zar 2007).
• Transdermal patches: May contain conducting metal (eg, aluminum); remove patch prior to MRI.
Other warnings/precautions:
• Tolerance: May occur; cross tolerance to other nitro compounds have been reported. Appropriate dosing is needed to minimize tolerance development.
Monitoring Parameters
Blood pressure, heart rate; consult individual institutional policies and procedures
