Nitroglycerin

Organic nitrate

ATC code: C01DA02(Glyceryl trinitrate)

Brand names: Nitrostat, Nitro-Dur, Nitrolingual

Updated 21 Jul 2026 · Methodology

Indications

Acute coronary syndrome

First line

Sublingual or intravenous nitroglycerin is used in acute coronary syndrome to reduce myocardial ischemia, control hypertension, and relieve pulmonary congestion. Intravenous infusion (start at 5–10 mcg/min, titrate to BP and pain) is indicated for ongoing ischemia, hypertension, or heart failure. Avoided in systolic BP below 90 mm Hg, right-ventricular infarction, and after recent phosphodiesterase-5 inhibitor use.

Sources

ICD-10: I20-I22 · ICD-11: BA4Z

Heart failure with reduced ejection fraction

Second line

In acute decompensated heart failure with pulmonary congestion and preserved arterial perfusion, intravenous nitroglycerin lowers preload, reduces dyspnea, and unloads the left ventricle. 2023 recommends use in patients with systolic BP above 110 mm Hg. Start infusion at 10–20 mcg/min with titration by BP and symptoms. Avoided in cardiogenic shock and systolic BP below 90 mm Hg.

Sources

ICD-10: I50.1 · ICD-11: BD11.2

Stable angina

First line

Sublingual nitroglycerin 0.3–0.6 mg or spray is the drug of choice for terminating a stable angina episode. Onset is 1–3 minutes, duration 20–30 minutes. / 2023 and 2024 recommend that every patient with stable CAD carry a sublingual formulation. If pain persists 5 minutes after the first dose, call emergency services – the picture may represent acute coronary syndrome. Prophylactic use 5–10 minutes before anticipated exertion is acceptable.

Sources

ICD-10: I20.8 · ICD-11: BA40.1

Vasospastic (Prinzmetal) angina

First line

Long-acting nitrates (nitroglycerin ointment, patch, sustained-release tablets, or isosorbide mono/dinitrate) prevent attacks in Prinzmetal vasospastic angina. 2023 recommends combined calcium channel blockers and long-acting nitrates as baseline therapy. A 8–12-hour nitrate-free interval is preserved between doses to prevent tolerance.

Sources

ICD-10: I20.1 · ICD-11: BA85

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Athletic endurance

Not recommended

Nitroglycerin is an organic nitrate and potent vasodilator. It is prescribed for acute angina relief and acute left heart failure ( 2024). In sports circles, nitroglycerin is occasionally promoted to improve blood flow to muscles before training. In healthy athletes without ischemic heart disease, no clinical studies of prophylactic use exist, and such use is dangerous. The drug has specific risks: severe hypotension with syncope, headache (common, marked), tolerance with regular use, and dangerous blood pressure drop combined with PDE5 inhibitors (sildenafil, tadalafil – strictly contraindicated). If nitroglycerin was prescribed to an athlete for training, consider seeking a second opinion.

Sources

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Releases nitric oxide that relaxes vascular smooth muscle. Decreases pre- and afterload, dilates coronary arteries. Used for angina attacks and acute heart failure. Absolutely contraindicated with PDE-5 inhibitors (sildenafil, etc.) due to severe hypotension.

Safety

Contraindications

Systolic BP below 90 mm Hg
PDE5 inhibitors within 24 hours (sildenafil, vardenafil) or 48 hours (tadalafil)
Riociguat (a guanylate cyclase stimulator)
Right-ventricular myocardial infarction
Cardiogenic shock and severe hypovolemia
Severe anemia
Increased intracranial pressure, recent intracranial hemorrhage
Constrictive pericarditis, cardiac tamponade
Hypertrophic obstructive cardiomyopathy with severe obstruction

Serious adverse effects

Life-threatening hypotension with phosphodiesterase-5 inhibitors
Circulatory collapse in right-ventricular myocardial infarction

Common adverse effects

Headache (throbbing, resolves in 20–30 minutes or after several doses)
Facial flushing, sensation of warmth
Hypotension, orthostatic reactions
Reflex tachycardia
Dizziness

Uncommon adverse effects

Tolerance with continuous long-term exposure (no nitrate-free interval)
Methemoglobinemia at very high doses
Contact dermatitis with patches

Pregnancy: can you take Nitroglycerin?

AEMPS summary of product characteristics (section 4.6): reproductive and developmental toxicity studies in rats and rabbits, using several routes of administration, showed no effect on embryos, fetuses or young animals, even at doses toxic to the dam. Topical nitroglycerin at up to 80 mg/kg/day in rats and 240 mg/kg/day in rabbits showed no evidence of fetal harm. There are no adequate well-controlled studies in pregnant women, and because animal studies do not always predict the human response, nitroglycerin should be used in pregnancy under medical direction and supervision and only if clearly needed.

Breastfeeding: can you take Nitroglycerin?

Data on nitroglycerin transfer into human milk are limited. A single sublingual dose is considered compatible with breastfeeding. With long-term nitrate therapy, alternatives are considered.

Calculate RID Full profile on NIH LactMed ↗

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Take sublingual tablets or spray seated or lying down: severe BP drop and syncope are possible standing. Store the drug in the original glass container, without transfer to plastic or pill organizers – nitroglycerin is volatile and loses activity with light, moisture, and heat. After opening, shelf life is 3–6 months depending on the form.

Dose titration

For an angina episode: 1 dose (0.3–0.6 mg tablet or 1 spray puff). If pain persists, repeat every 5 minutes, up to 3 doses. If pain does not resolve 5 minutes after the first dose, call emergency services. Prophylactically before exertion – 1 dose 5–10 minutes earlier. Long-term therapy uses sustained-release forms with an 8- to 12-hour nitrate-free interval.

Monitoring

On first sublingual use, assess tolerance: severe hypotension (systolic BP below 90 mm Hg) or syncope prompts discontinuation and reassessment. With long-acting nitrate therapy, monitor for tolerance: more frequent attacks or need for higher doses indicates a need to revise the regimen and ensure a nitrate-free interval.

Special situations

Phosphodiesterase-5 inhibitors (sildenafil, vardenafil, avanafil, tadalafil) combined with nitroglycerin produce life-threatening hypotension. Before starting angina therapy in a man, ask about erectile dysfunction drugs. After sildenafil/vardenafil – 24 hours, after tadalafil – 48 hours nitrates are withheld. Riociguat in pulmonary hypertension is an absolute contraindication to nitrates throughout treatment.

Common myths

Myth: “sublingual nitroglycerin causes addiction”. Fact: sublingual formulations do not cause addiction – they are used episodically. Tolerance is a pharmacological phenomenon of continuous exposure (24-hour patch, sustained-release without breaks), not situational use.

Myth: “nitroglycerin headache is dangerous”. Fact: throbbing headache is an expected adverse effect of peripheral vasodilation. It resolves in 20–30 minutes or after several uses with partial tolerance to this effect.

Myth: “if pain persists after 3 tablets, keep taking them”. Fact: if pain persists 5 minutes after the first dose, call emergency services. This may be acute coronary syndrome requiring thrombolysis or PCI, not more nitrate.

Drug–drug interactions

7 pairs found. Sorted from critical to minor.

CriticalRiociguatSoluble guanylate cyclase (sGC) stimulator

Mechanism

Riociguat activates sGC independently of NO. Nitrate adds NO – synergistic systemic hypotension. Section 4.3.

Symptoms

Severe hypotension.

Management

Combination contraindicated.

Sources

Pair details →Riociguat →

CriticalSildenafilPhosphodiesterase type 5 inhibitors (PDE5)

Mechanism

Sildenafil blocks phosphodiesterase-5, slowing breakdown of cGMP – the intracellular mediator of vascular relaxation. Nitroglycerin raises cGMP production. Co-administration sharply amplifies vasodilation – severe systemic hypotension develops. Fatal cases have been reported.

Symptoms

Sudden drop in blood pressure: dizziness, visual greying, syncope, shock. In ischaemic heart disease, risk of myocardial infarction from coronary perfusion collapse.

Management

The combination is not prescribed. After sildenafil, nitrates are permitted only after 24 hours. After tadalafil (long-acting), only after 48 hours. In acute coronary syndrome after recent sildenafil, replace nitrates with morphine and oxygen; for preload reduction, use furosemide.

Sources

Pair details →Sildenafil →

CriticalTadalafilPhosphodiesterase type 5 (PDE-5) inhibitor

Mechanism

Both raise cGMP in vascular smooth muscle. Synergistic systemic vasodilation – fatal hypotension with MI. Tadalafil's long T1/2 requires 48-hour washout.

Symptoms

Sudden hypotension, syncope, MI.

Management

Combination contraindicated. 48 hours between tadalafil and nitrate.

Sources

Pair details →Tadalafil →

CriticalVardenafilPhosphodiesterase type 5 (PDE-5) inhibitor

Mechanism

Same as tadalafil-nitrate.

Symptoms

Fatal hypotension.

Management

Combination contraindicated. 24-hour washout.

Sources

Pair details →Vardenafil →

ModerateAlprazolamBenzodiazepines. Short-to-medium-acting anxiolytics

Mechanism

Additive hypotension with sublingual nitroglycerin. Alprazolam sedation may worsen dizziness.

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.

Management

The patient takes the first nitroglycerin dose sitting or lying down. Warn the patient about fall risk after nitroglycerin while on alprazolam.

Sources

FDA: Xanax (alprazolam) prescribing information (2016)

Pair details →Alprazolam →

ModerateAmitriptylineTricyclic antidepressants (TCA)

Mechanism

Additive orthostatic hypotension with sublingual nitroglycerin. Amitriptyline blocks α1-adrenoceptors and reduces compensatory response.

Symptoms

Postural dizziness, syncope, fatigue. Older patients: fall and fracture risk.

Management

The patient takes the first nitroglycerin dose sitting or lying down. Older patients: enhanced fall monitoring. Alternative antidepressants without α1-blockade: sertraline or agomelatine.

Sources

FDA: Amitriptyline HCl tablets prescribing information (2014)

Pair details →Amitriptyline →

ModerateAmlodipineCalcium channel blockers (dihydropyridines)

Mechanism

Additive hypotension with sublingual or parenteral nitroglycerin. Both drugs are vasodilators (amlodipine – calcium channel blocker, nitroglycerin – nitrate vasodilator).

Symptoms

Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.

Management

The combination is acceptable in angina. The patient takes the first nitroglycerin dose sitting or lying down. Older patients: fall risk after nitroglycerin. Advise the patient to consult a clinician with frequent episodes.

Sources

FDA: Verapamil hydrochloride tablet (Zydus Lifesciences Limited) – Prescribing Information (2017)

Pair details →Amlodipine →

Label mentions28 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

Criticalinhibidores de la PDE5class named in the label
«Uso concomitante de inhibidores de la fosfodiesterasa tipo 5 (PDE5), como el sildenafilo, tadalafilo, vardenafilo,ya que pueden potenciar el efecto vasodilatador de Cordiplast, provocando una…»
AEMPS, section 4.3 · Open on CIMA
CriticalPDE5 inhibitorsclass named in the label
«CONTRAINDICATIONS: Use of phosphodiesterase type 5 (PDE-5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulators. ( 4.1 , 7.1 )»
FDA, section 4 · Open on DailyMed
CriticalRiociguat
«Durante el tratamiento con nitratos, no se debe usar riociguat, un estimulador de la guanilato ciclasa soluble (ver sección 4.5).»
AEMPS, section 4.3 · Open on CIMA
CriticalRiociguat
«PDE-5-Inhibitors and sGC-Stimulators: Do not use nitroglycerin sublingual tablets in patients who are taking the soluble guanylate cyclase stimulators, such as riociguat. Concomitant use can cause…»
FDA, section 4 · Open on DailyMed
CriticalSildenafil
«Uso concomitante de inhibidores de la fosfodiesterasa tipo 5 (PDE5), como el sildenafilo, tadalafilo, vardenafilo,ya que pueden potenciar el efecto vasodilatador de Cordiplast, provocando una…»
AEMPS, section 4.3 · Open on CIMA
CriticalSildenafil
«CONTRAINDICATIONS: Use of phosphodiesterase type 5 (PDE-5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulators. ( 4.1 , 7.1 )»
FDA, section 4 · Open on DailyMed
CriticalTadalafil
«Uso concomitante de inhibidores de la fosfodiesterasa tipo 5 (PDE5), como el sildenafilo, tadalafilo, vardenafilo,ya que pueden potenciar el efecto vasodilatador de Cordiplast, provocando una…»
AEMPS, section 4.3 · Open on CIMA
CriticalTadalafil
«CONTRAINDICATIONS: Use of phosphodiesterase type 5 (PDE-5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulators. ( 4.1 , 7.1 )»
FDA, section 4 · Open on DailyMed
CriticalVardenafil
«Uso concomitante de inhibidores de la fosfodiesterasa tipo 5 (PDE5), como el sildenafilo, tadalafilo, vardenafilo,ya que pueden potenciar el efecto vasodilatador de Cordiplast, provocando una…»
AEMPS, section 4.3 · Open on CIMA
CriticalVardenafil
«CONTRAINDICATIONS: Use of phosphodiesterase type 5 (PDE-5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulators. ( 4.1 , 7.1 )»
FDA, section 4 · Open on DailyMed
MajorDihydroergotamine
«Ergotamine: Oral administration of nitroglycerin markedly decreases the first-pass metabolism of dihydroergotamine and subsequently increases its oral bioavailability. Ergotamine is known to…»
FDA, section 7 · Open on DailyMed
MajorErgotamine
«DRUG INTERACTIONS: Ergotamine: increased bioavailability of ergotamine. Avoid concomitant use. ( 7.2 )»
FDA, section 7 · Open on DailyMed
Acetylsalicylic acid
«La administración simultánea de nitroglicerina con ácido acetilsalicílico puede potenciar los efectos de la disminución de la presión sanguínea por la nitroglicerina.»
AEMPS, section 4.5 · Open on CIMA
AINEclass named in the label
«Los medicamentos antiinflamatorios no esteroideos (AINE), excepto el ácido acetilsalicílico, pueden disminuir la respuesta terapéutica a Cordiplast.»
AEMPS, section 4.5 · Open on CIMA
antidepresivos tricíclicosclass named in the label
«El tratamiento simultáneo de fármacos con propiedades hipotensoras, p. ej., betabloqueantes, antagonistas de canales de calcio, vasodilatadores (p. ej., inhibidores de PDE-5 como sildenafilo…»
AEMPS, section 4.5 · Open on CIMA
antipsicóticosclass named in the label
«El tratamiento simultáneo de fármacos con propiedades hipotensoras, p. ej., betabloqueantes, antagonistas de canales de calcio, vasodilatadores (p. ej., inhibidores de PDE-5 como sildenafilo…»
AEMPS, section 4.5 · Open on CIMA
betabloqueantesclass named in the label
«El tratamiento simultáneo de fármacos con propiedades hipotensoras, p. ej., betabloqueantes, antagonistas de canales de calcio, vasodilatadores (p. ej., inhibidores de PDE-5 como sildenafilo…»
AEMPS, section 4.5 · Open on CIMA
Dihydroergotamine
«Los informes sugieren que cuando se administra simultáneamente, la nitroglicerina, puede aumentar los niveles en sangre de la dihidroergotamina y sus efectos. Es necesaria una especial atención en…»
AEMPS, section 4.5 · Open on CIMA
diuréticosclass named in the label
«El tratamiento simultáneo de fármacos con propiedades hipotensoras, p. ej., betabloqueantes, antagonistas de canales de calcio, vasodilatadores (p. ej., inhibidores de PDE-5 como sildenafilo…»
AEMPS, section 4.5 · Open on CIMA
inhibidores de la ECAclass named in the label
«El tratamiento simultáneo de fármacos con propiedades hipotensoras, p. ej., betabloqueantes, antagonistas de canales de calcio, vasodilatadores (p. ej., inhibidores de PDE-5 como sildenafilo…»
AEMPS, section 4.5 · Open on CIMA

From other drugs’ labels

CriticalVardenafil
«Estudios in vivo: En un estudio en 18 varones sanos, al administrar vardenafilo (10 mg) a diferentes intervalos de tiempo (entre 1 h y 24 h) antes de una dosis sublingual de nitroglicerina (0.4 mg)…»
AEMPS, section 4.5 · Open on CIMA
CriticalVardenafil
«Potential for Pharmacodynamic Interactions with Vardenafil: Concomitant use of vardenafil and nitrates and nitric oxide donors is contraindicated. The blood pressure lowering effects of sublingual…»
FDA, section 7 · Open on DailyMed
ModerateCaptopril
«Otros agentes antihipertensivos: captopril se ha administrado de forma segura con otros agentes antihipertensivos utilizados comúnmente (betabloqueantes y bloqueantes de los canales de calcio de…»
AEMPS, section 4.5 · Open on CIMA
ModerateDiltiazem
«Nitratos : durante el tratamiento con diltiazem puede administrarse nitroglicerina sublingual cuando ésta sea requerida, así como, nitratos de corta o larga duración de acción, pero cuando se…»
AEMPS, section 4.5 · Open on CIMA
Acetylcysteine
«Antibióticos: Se ha demostrado que la administración simultánea de nitroglicerina y acetilcisteína produce una hipotensión significativa e incremento de la dilatación de la arteria temporal. Si es…»
AEMPS, section 4.5 · Open on CIMA
Enalapril
«El uso concomitante de estos fármacos puede aumentar los efectos hipotensores de enalapril. El uso concomitante con nitroglicerina y otros nitratos, u otros vasodilatadores, puede reducir aún más la…»
AEMPS, section 4.5 · Open on CIMA
Labetalol
«Drug Interactions: Labetalol hydrochloride blunts the reflex tachycardia produced by nitroglycerin without preventing its hypotensive effect. If labetalol hydrochloride is used with nitroglycerin in…»
FDA, section 7 · Open on DailyMed
Lisinopril
«Otros agentes antihipertensivos: El uso concomitante de estos agentes puede aumentar los efectos hipotensores de lisinopril. El uso concomitante con nitroglicerina y otros nitratos u otros…»
AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Nitroglycerin used for?

Nitroglycerin is evaluated for the following indications with varying evidence strength: Heart failure with reduced ejection fraction (evidence tier A), Stable angina (evidence tier A), Acute coronary syndrome (evidence tier A). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Nitroglycerin?

Common side effects of Nitroglycerin (≥ 1 in 100): Headache (throbbing, resolves in 20–30 minutes or after several doses), Facial flushing, sensation of warmth, Hypotension, orthostatic reactions, Reflex tachycardia, Dizziness. See the Safety section for uncommon and serious reactions.

Is Nitroglycerin safe during pregnancy?

Is Nitroglycerin compatible with breastfeeding?

Data on nitroglycerin transfer into human milk are limited. A single sublingual dose is considered compatible with breastfeeding. With long-term nitrate therapy, alternatives are considered.

Who should not take Nitroglycerin?

Nitroglycerin is contraindicated in: Systolic BP below 90 mm Hg; PDE5 inhibitors within 24 hours (sildenafil, vardenafil) or 48 hours (tadalafil); Riociguat (a guanylate cyclase stimulator); Right-ventricular myocardial infarction; Cardiogenic shock and severe hypovolemia. Full list in the Safety section.

“sublingual nitroglycerin causes addiction”

sublingual formulations do not cause addiction – they are used episodically. Tolerance is a pharmacological phenomenon of continuous exposure (24-hour patch, sustained-release without breaks), not situational use.

“nitroglycerin headache is dangerous”

throbbing headache is an expected adverse effect of peripheral vasodilation. It resolves in 20–30 minutes or after several uses with partial tolerance to this effect.

“if pain persists after 3 tablets, keep taking them”

if pain persists 5 minutes after the first dose, call emergency services. This may be acute coronary syndrome requiring thrombolysis or PCI, not more nitrate.

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMALabel dated 09/27/2025
FDA / DailyMedLabel dated 08/10/2026
GRLS

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