Also known as nitroglycerine, trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane.

Used as an active ingredient in the manufacture of explosives, mostly dynamite.

Pregnancy category US: C (Risk not ruled out)

Routes of administration- Intravenous, by mouth, under the tongue, and topical.

Bioavailability <1%.

Metabolism is by the liver.

Biological half-life 3 min.

Used as a potent vasodilator to treat heart conditions, such as angina pectoris and chronic heart failure.

Beneficial effects are due to nitroglycerin being converted to nitric oxide, a potent venodilator.

The enzyme for this conversion to nitric oxide is mitochondrial aldehyde dehydrogenase (ALDH2).

Nitroglycerin is available in sublingual tablets, sprays, ointments, and patches.

It belongs to nitrates, which includes many other nitrates like isosorbide dinitrate and isosorbide mononitrate.

These nitrates exert their effect by being converted to nitric oxide in the body by mitochondrial aldehyde dehydrogenase (ALDH2).

Nitric oxide is a potent natural vasodilator.

It is used for angina pectoris, caused by inadequate flow of blood and oxygen to the heart and as a potent antihypertensive agent.

It corrects the imbalance between the flow of oxygen and blood to the heart.

At low dose, nitroglycerin dilates veins more than arteries, thereby reducing preload.

Decreasing preload is thought to be its primary mechanism of action.

With decreased preload, the heart has less blood to pump, which decreases oxygen requirement since the heart does not have to work as hard.

A smaller preload reduces the pressure exerted on the walls of the heart. which decreases the compression of heart arteries to allow more blood to flow through the heart.

At higher doses, it dilates arteries, reducing afterload, the pressure against which the heart must pump.

The improved myocardial oxygen demand vs oxygen delivery ratio leads to the effects during episodes of angina pectoris of subsiding of chest pain, decrease of blood pressure, increase of heart rate, and orthostatic hypotension.

In those experiencing angina with certain physical activities, can often prevent symptoms by taking nitroglycerin 5 to 10 minutes before the activity.

Overdoses of nitroglycerin may generate methemoglobinemia.

Some forms of nitroglycerin last much longer than others.

Continuous exposure to nitrates has been shown to cause the body to stop responding normally to this medicine.

Patches should be removed at night, to restore its responsiveness to nitrates.

Nitroglycerin should not be given if certain inhibitors such as sildenafil, tadalafil, or vardenafil have been taken within the previous 12 hours as the combination of the two could cause a serious drop in blood pressure.

Shorter-acting preparations of nitroglycerin can be used several times a day with less risk of developing tolerance.

People can be exposed to nitroglycerin in the workplace by breathing it in, skin absorption, swallowing it, or eye contact.

Leave a Reply

Your email address will not be published. Required fields are marked *