Generic
Nitroglycerin
33 brands available in the market
At a glance
Nitroglycerin is a vasodilator used for acute relief or prophylaxis of angina pectoris. It relaxes vascular smooth muscle to dilate arteries and veins, reducing heart workload and improving coronary blood flow.
Description
Nitroglycerin is an organic nitrate with vasodilator effects on both arteries and veins. It relaxes vascular smooth muscle, producing vasodilator effect on peripheral arteries and veins (more prominent on veins). Dilation of large veins promotes peripheral pooling of blood and decreases venous return, reducing left ventricular end-diastolic pressure (pre-load). Arteriolar relaxation reduces systemic vascular resistance and arterial pressure (after-load).
Indications
- Acute relief of angina pectoris
- Prophylaxis of angina pectoris due to coronary artery disease
Therapeutic class
Nitrates: Coronary Vasodilators
Pharmacological class
Organic Nitrate
Pharmacology
Nitroglycerin forms nitric oxide (NO) which activates guanylate cyclase, increasing cyclic GMP in smooth muscle. This leads to dephosphorylation of myosin light chains, regulating smooth muscle contractile state and resulting in vasodilation.
Mechanism of action
Dilates blood vessels to reduce heart workload and relieve chest pain.
Dosage
Sublingual Tablet:
- Acute anginal attack: 0.5 mg dissolved under tongue; repeat every 5 minutes; seek emergency if pain persists after 3 tablets in 15 minutes
Sustained-Release Tablet:
- 2.6 mg: 1 tablet twice daily before meals; may increase to 2-3 tablets twice daily
- 6.4 mg: 1 tablet twice daily
Spray:
- At onset: 1-2 metered doses under tongue; repeat every 5 minutes; max 3 sprays in 15 minutes
- Prophylaxis: 5-10 minutes before activities
Administration
- Sublingual: Dissolve under tongue
- Spray: Spray under tongue; do not inhale; max 3 sprays in 15 minutes
- Prime before first use (5 sprays); if not used for 6 weeks (1 spray); if not used for 3 months (5 sprays)
- Use while resting and sitting
Missed dose
If you miss a dose, use it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Headache
- Flushing
- Hypotension
Precautions & warnings
- Use only the smallest effective dose
- Excessive use may lead to tolerance
- Caution in volume-depleted or hypotensive patients
- Avoid alcohol
Contraindications
- Patients using PDE5 inhibitors (sildenafil, vardenafil, tadalafil)
- Severe anemia
- Increased intracranial pressure
- Hypersensitivity
- Acute circulatory failure or shock
Drug interactions
- Additive hypotensive effects with antihypertensives, beta-blockers or phenothiazines
- Hypotension with alcohol
- Enhanced vasodilatory effects with aspirin
Food interactions
Alcohol may cause hypotension.
Use in pregnancy
Use in Pregnancy: No evidence of safety in pregnancy; use only if essential.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Unknown if excreted in human milk; use only if essential.
Pediatric use
Safety and effectiveness not established in pediatric patients.
Geriatric use
Elderly may require dose adjustment.
Renal / hepatic impairment
Renal Impairment: Caution in kidney disease; dose adjustment may be needed.
Hepatic Impairment: Caution in liver disease; dose adjustment may be needed.
Overdose effects
Overdose: Vomiting, restlessness, hypotension, cyanosis, methemoglobinemia, tachycardia, syncope; symptomatic treatment.
Storage conditions
Keep out of reach of children; store in a dry place, below 25°C and protected from light.
Chemical structure
Nitroglycerin