nitroglycerin IV

Action and Spectrum

Actions and spectrum: 

nitroglycerin IV is a vasodilator medication that relaxes smooth muscles, leading to dilation of blood vessels and improved blood flow. It is used primarily to treat angina (chest pain) and heart failure. nitroglycerin IV works by releasing nitric oxide in the body, which causes the smooth muscle cells in the blood vessels to relax and widen, resulting in increased blood flow and decreased workload on the heart. 

nitroglycerin IV is also used in emergency settings to treat hypertensive crises and pulmonary edema. In these situations, nitroglycerin IV helps to reduce blood pressure and relieve the workload on the heart and lungs. nitroglycerin IV is typically administered in a hospital or clinical setting, as it requires careful monitoring of blood pressure and other vital signs. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Serious 

• Syncope 
• Exfoliative dermatitis 
• Rebound hypertension 
• Methemoglobinemia (rare) 
• Prolonged bleeding time 
• Unstable angina 
• Thrombocytopenia 

Common 

• Hypotension 
• Dizziness 
• Blurred vision 
• Nausea/Vomiting 
• Xerostomia 
• Headache 
• Tachycardia 
• Lightheadedness 
• Flushing 
• Nervousness  
• Dyspnea 

Black Box Warning

Black Box Warning: 

nitroglycerin IV has a black box warning for its potential to cause hypotension. It should be administered only under close medical supervision with continuous blood pressure monitoring.

It is contraindicated in patients with hypotension or those who are in shock, as well as in patients with hypersensitivity to nitroglycerin or any other nitrates. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Hypersensitivity to nitroglycerin or other nitrates 
• Severe anemia 
• Increased intracranial pressure 
• Cardiac tamponade 
• Constrictive pericarditis 
• Aortic/mitral stenosis 
• Hypovolemia 
• Use of sildenafil or another phosphodiesterase inhibitor within the last 24 hours 
• Known hypersensitivity to adhesive dressings or their components if nitroglycerin transdermal patch is used.

Caution: 

nitroglycerin IV should be used with caution in patients with hypotension, volume depletion, or those who are hemodynamically unstable. It should also be used under caution in patients with severe anemia, hypothyroidism, and increased intracranial pressure. Patients with severe renal or hepatic dysfunction may require dosage adjustments. nitroglycerin IV should be used with caution in patients who are taking drugs that affect blood pressure, such as beta-blockers, calcium channel blockers, or other vasodilators. It should also be used under caution in patients with myocardial infarction, angina pectoris, or congestive heart failure.  

Comorbidities: 

• Hypotension or hypovolemia: nitroglycerin may further decrease blood pressure in patients with low blood pressure or low blood volume. 
• Increased intracranial pressure (ICP): nitroglycerin may increase ICP due to its vasodilatory effects, which may worsen brain injury or edema. 
• Severe anemia: nitroglycerin may cause coronary steal syndrome, where blood is diverted from ischemic areas of the heart to areas with normal blood flow, exacerbating myocardial ischemia in patients with severe anemia. 
• Hypertrophic obstructive cardiomyopathy (HOCM): nitroglycerin may cause worsen HOCM by decreasing preload, increasing outflow obstruction, and reducing cardiac output. 
• Severe renal or hepatic impairment: nitroglycerin may accumulate in patients having severe hepatic or renal impairment due to decreased drug clearance, increasing the risk of hypotension and other adverse effects. 
• Hypersensitivity: nitroglycerin is contraindicated in patients with a known hypersensitivity to the drug. 

Pregnancy / Lactation

Pregnancy consideration: US FDA pregnancy category: C 

Lactation: It is not known whether the nitroglycerin is excreted in human milk  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women. 
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

nitroglycerin IV primarily affects veins and, to a lesser extent, arteries. nitroglycerin is converted to nitric oxide (NO) in the body, which activates guanylate cyclase and leads to increased levels of cyclic guanosine monophosphate (cGMP). Elevated cGMP levels result in decreased intracellular calcium concentrations, leading to vasodilation, and decreased cardiac preload and afterload. nitroglycerin is also thought to enhance collateral blood flow and increase oxygen supply to ischemic tissues.  

Pharmacodynamics: 

nitroglycerin IV is a potent vasodilator that causes relaxation of vascular smooth muscle, resulting in dilation of peripheral arteries and veins. It also relaxes the smooth muscle in the walls of the coronary arteries, improving blood flow to the heart. nitroglycerin IV reduces cardiac preload and afterload, which decreases myocardial oxygen demand and improves cardiac output. It also dilates the pulmonary vasculature, reducing pulmonary capillary wedge pressure and improving pulmonary arterial oxygenation. 

The onset of action of nitroglycerin IV is rapid, with the maximum effect occurring within 1-5 minutes of administration. The duration of action is short, typically lasting 5-10 minutes after discontinuation of the infusion. The pharmacodynamics of nitroglycerin IV are dose-dependent, with higher doses resulting in greater vasodilation and hemodynamic effects.  

Pharmacokinetics: 

Absorption 

nitroglycerin is administered intravenously, and therefore there is no absorption step required. 

Distribution 

nitroglycerin has a rapid distribution phase and a small volume of distribution. It gets metabolized in the liver and extrahepatic tissues, with a clearance rate of approximately 2 L/min. 

Metabolism 

nitroglycerin is metabolized in the liver by glutathione and glutathione S-transferases into the active metabolite, nitric oxide, which activates the enzyme guanylate cyclase, leading to the formation of cyclic guanosine monophosphate (cGMP). 

Elimination and excretion 

The metabolites of nitroglycerin are excreted in the urine, with a small fraction excreted in the bile. The elimination half-life of nitroglycerin is 1-4 minutes. 

Adminstartion

Administration: 

nitroglycerin IV is administered through a slow intravenous infusion. The infusion rate and dose depend on the patient’s condition, the indication for use, and the formulation used. The infusion rate must be adjusted to achieve the desired therapeutic effect by minimizing adverse effects.

Patient Information Leaflet

Patient information leaflet 

Generic Name: nitroglycerin IV 

Pronounced: “Nye-troh-GLIS-er-in”  

Why do we use nitroglycerin IV? 

nitroglycerin IV is a medication used in the treatment of angina (chest pain) and heart failure. It works by dilating blood vessels, increasing blood flow to the heart, and reducing the heart’s workload, thereby relieving symptoms of angina, and improving heart function in heart failure.

nitroglycerin IV is also used in the treatment of hypertension (high blood pressure) and pulmonary edema (fluid in the lungs). Additionally, it may be used during surgical procedures to control blood pressure and reduce the risk of bleeding.