indication

For the prevention of angina

pharmacology

Nitroglycerin, an organic nitrate, is available in many forms as a vasodilator. Nitroglycerin is used in the treatement of angina pectoris and perioperative hypertension, to produce controlled hypotension during surgical procedures, to treat hypertensive emergencies, and to treat congestive heart failure associated with myocardial infarction.

mechanism of action

Similar to other nitrites and organic nitrates, nitroglycerin is converted to nitric oxide (NO), an active intermediate compound which activates the enzyme guanylate cyclase. This stimulates the synthesis of cyclic guanosine 3',5'-monophosphate (cGMP) which then activates a series of protein kinase-dependent phosphorylations in the smooth muscle cells, eventually resulting in the dephosphorylation of the myosin light chain of the smooth muscle fiber. The subsequent release of calcium ions results in the relaxation of the smooth muscle cells and vasodilation.

toxicity

Increased intracranial pressure, with any or all of persistent throbbing headache, confusion, and moderate fever; Vertigo; Palpitations; Visual disturbances; Nausea and vomiting (possibly with colic and even bloody diarrhea); Syncope (especially in the upright posture); Air hunger and dyspnea, later followed by reduced ventilatory effort; Diaphoresis, with the skin either flushed or cold and clammy; Heart block and bradycardia; Paralysis; Coma; Seizures; Death.

biotransformation

Hepatic, cytochrome P450 (P450) is a key enzyme of organic nitrate biotransformation

half life

3 minutes

drug interactions

Alteplase: IV nitroglycerin may decrease the effect of alteplase.

Dihydroergotamine: Possible antagonism of action

Dihydroergotoxine: Possible antagonism of action

Ergonovine: Possible antagonism of action

Ergotamine: Possible antagonism of action

Methylergonovine: Possible antagonism of action

Methysergide: Possible antagonism of action

Sildenafil: Possible significant hypotension with this combination

Tadalafil: The vasodilatory effects of Nitroglycerin may be increased by Tadalafil. Severe hypotension may occur. Concomitant therapy is contraindicated.

Treprostinil: Additive hypotensive effect. Monitor antihypertensive therapy during concomitant use.

Udenafil: The vasodilatory effects of Nitroglycerin may be increased by Udenafil. Severe hypotension may occur. Concomitant therapy is contraindicated.

Vardenafil: The vasodilatory effects of Nitroglycerin may be increased by Vardenafil. Severe hypotension may occur. Concomitant therapy is contraindicated.