Nitroglycerin is a cornerstone medication in cardiovascular therapy, primarily used for the prevention and treatment of angina pectoris. As an organic nitrate, it functions as a potent vasodilator, specifically targeting venous and arterial smooth muscle to reduce cardiac preload and afterload. This mechanism decreases myocardial oxygen demand while improving coronary blood flow, offering prompt symptomatic relief during acute angina episodes and providing prophylactic protection against anticipated exertional or stress-induced chest pain. Available in sublingual, oral, topical, and intravenous formulations, nitroglycerin remains an essential tool in both outpatient management and acute cardiac care settings.

Features

• Active ingredient: Nitroglycerin (glyceryl trinitrate)
• Available forms: Sublingual tablets, sprays, ointments, transdermal patches, extended-release capsules, and intravenous solutions
• Rapid onset of action: Sublingual forms act within 1-3 minutes
• Duration varies by formulation: from 10-30 minutes (sublingual) to 8-14 hours (transdermal)
• Multiple strength options: 0.3 mg, 0.4 mg, 0.6 mg sublingual tablets; 2% ointment; 0.1 mg/hr to 0.8 mg/hr patches
• Stable chemical composition with proper storage
• Manufactured under strict pharmaceutical standards

Benefits

• Provides rapid relief from acute angina attacks within minutes of administration
• Reduces frequency and severity of angina episodes with regular prophylactic use
• Decreases myocardial oxygen demand through balanced vasodilation
• Improves exercise tolerance and quality of life in patients with chronic angina
• Offers flexible administration routes tailored to individual patient needs
• May help manage acute congestive heart failure and hypertensive emergencies in hospital settings

Common use

Nitroglycerin is primarily indicated for the management of angina pectoris caused by coronary artery disease. It is used both acutely to abort ongoing angina attacks and prophylactically to prevent anticipated episodes related to physical exertion or emotional stress. In hospital settings, intravenous nitroglycerin is employed for controlling blood pressure in hypertensive emergencies, managing acute congestive heart failure, and treating myocardial ischemia during acute coronary syndromes. Some off-label uses include esophageal spasm relief and tocolysis in preterm labor, though these applications require careful medical supervision.

Dosage and direction

Sublingual tablets/spray: For acute angina, place 1 tablet under the tongue or spray 1-2 doses onto or under the tongue at the first sign of attack. Dose may be repeated every 5 minutes for maximum of 3 doses in 15 minutes. For prophylaxis, use 5-10 minutes before anticipated exertion.

Ointment: Apply 1/2 to 2 inches (15-50 mm) every 8 hours, starting with smaller dose. Spread thin layer on clean, dry, hairless skin area (chest, arm, thigh). Rotate application sites.

Transdermal patches: Apply one patch to clean, dry, hairless skin daily. Start with 0.1-0.2 mg/hr patch. Remove after 12-14 hours to provide 10-12 hour nitrate-free interval.

Extended-release capsules: 2.5-9 mg every 8-12 hours, swallowed whole.

Intravenous: Initiated in hospital setting only. Typical starting dose: 5 mcg/min, titrated by 5 mcg/min every 3-5 minutes until response achieved.

Always follow specific prescribing physician’s instructions regarding dosage and administration.

Precautions

• Use caution in patients with hypotension, volume depletion, or right ventricular infarction
• Tolerance may develop with continuous use; employ nitrate-free interval (10-12 hours daily) for transdermal and oral forms
• Avoid sudden discontinuation due to risk of rebound angina
• Headaches are common initially; usually diminish with continued use
• Orthostatic hypotension may occur; rise slowly from sitting/lying position
• May exacerbate angina caused by hypertrophic cardiomyopathy
• Use with caution in elderly patients due to increased sensitivity to hypotensive effects
• Store medication properly as nitroglycerin is sensitive to light, moisture, and heat

Contraindications

• Hypersensitivity to nitrates, nitrites, or any component of the formulation
• Concurrent use with phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil)
• Severe anemia
• Increased intracranial pressure
• Circulatory failure and shock
• Constrictive pericarditis and cardiac tamponade
• Hypertrophic obstructive cardiomyopathy
• Closed-angle glaucoma (relative contraindication)
• Severe hypotension (systolic BP <90 mmHg)

Possible side effect

Common (≥1%):

• Headache (most frequent, often dose-related)
• Dizziness, lightheadedness
• Flushing
• Hypotension, orthostatic hypotension
• Reflex tachycardia
• Nausea, vomiting

Less common:

• Syncope
• Weakness
• Palpitations
• Parodoxical bradycardia
• Dermatitis with transdermal forms
• Dry mouth
• blurred vision

Rare but serious:

• Methemoglobinemia (with high doses)
• Severe hypotension leading to shock
• Myocardial infarction (if used inappropriately in certain cardiac conditions)
• Allergic reactions including rash, pruritus, angioedema

Drug interaction

Major interactions:

• Phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil): Profound hypotension, potentially fatal
• Other vasodilators (ACE inhibitors, ARBs, calcium channel blockers): Additive hypotensive effect
• Alcohol: Enhanced vasodilation and hypotension
• Heparin: Reduced anticoagulant effect (with IV nitroglycerin)
• Aspirin: Increased nitroglycerin concentrations
• Ergot derivatives: May antagonize coronary vasodilation

Moderate interactions:

• Beta-blockers: Additive bradycardic effects
• Diuretics: Enhanced hypotensive effect
• Tricyclic antidepressants: Additive hypotensive effect
• Sympathomimetics: Possible reduced antianginal effect

Missed dose

For scheduled prophylactic dosing (ointments, patches, extended-release capsules): Apply or take the missed dose as soon as remembered, unless it is almost time for the next dose. Do not double the dose to make up for a missed one. For sublingual forms used as needed for acute attacks, no specific missed dose protocol applies since it is not scheduled medication.

Overdose

Symptoms: Severe hypotension, throbbing headache, dizziness, palpitations, visual disturbances, nausea/vomiting, sweating, syncope, cyanosis with methemoglobinemia, air hunger, dyspnea, bradycardia or tachycardia, heart block, paradoxical angina, circulatory collapse.

Management: Discontinue nitroglycerin immediately. Place patient in recumbent position with legs elevated. Administer oxygen. Support blood pressure with IV fluids if needed. For severe hypotension, consider alpha-adrenergic agonists (phenylephrine). For methemoglobinemia (>30% or symptomatic), administer methylene blue 1-2 mg/kg IV over 5 minutes. Hemodialysis not effective. Seek immediate medical attention.

Storage

• Store at controlled room temperature (20-25°C or 68-77°F)
• Protect from light, moisture, and heat
• Keep sublingual tablets in original glass container with cotton removed
• Tightly close container after each use
• Do not transfer to other containers
• Do not store in bathroom or near kitchen sink
• Keep away from children and pets
• Discard unused sublingual tablets 3-6 months after opening bottle
• Do not use if tablets do not fizzle or burn under tongue

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting, changing, or stopping any medication. The content provided is not a substitute for professional medical advice, diagnosis, or treatment. Never disregard professional medical advice or delay seeking it because of something you have read here. Individual medical needs vary, and only your healthcare provider can determine what is appropriate for your specific situation.

Reviews

“After my angina diagnosis, nitroglycerin has been a lifesaver. The sublingual tablets work within minutes when I feel chest pain coming on. The headaches were bothersome at first but diminished after the first week.” - James R., 68

“As a cardiologist, I’ve prescribed nitroglycerin for decades. It remains one of the most effective and rapid-acting antianginal medications available. The various formulations allow us to tailor therapy to individual patient needs.” - Dr. Eleanor Mitchell, MD

“The transdermal patch system has significantly improved my quality of life. I apply it in the morning and remove it at night, which prevents tolerance development. My angina episodes have reduced from several per week to maybe one per month.” - Margaret T., 72

“Emergency physicians rely on IV nitroglycerin for managing hypertensive crises and acute heart failure. Its titratability and rapid onset make it invaluable in critical care settings.” - Dr. Benjamin Carter, Emergency Medicine

“I was hesitant about using medication, but my doctor explained how nitroglycerin could prevent heart damage during angina attacks. The spray form is convenient and discrete when I need it in public situations.” - Robert L., 61