nitroglycerin

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nitroglycerin

 [ni″tro-glis´er-in]
a chemical well known as an explosive but also having medical uses; it is a vasodilator and is used medically especially in the prophylaxis and treatment of angina pectoris. Called also glyceryl trinitrate.

The most common means of administration has been the sublingual tablet, which is placed under the tongue when the attack occurs; it is not effective if swallowed. Under the tongue, it quickly dissolves and should give relief within 1 or 2 minutes. It may cause transient palpitation, flushing, faintness, and perhaps headache. The patient who is taking nitroglycerin should keep it nearby at all times, stored in a tightly closed dark glass container free from heat and moisture. It is not addicting and there is no limit to the number that may be taken in a 24-hour period; however, no more than three tablets should be taken at 5 minute intervals during an attack. If no relief is obtained 15 minutes after the third tablet is taken, the physician should be notified immediately.

Several alternatives to sublingual tablets have been developed that also are absorbed through the oral mucosa, including extended release buccal tablets, which are held between the lip or cheek and upper gum, and a lingual aerosol, which is sprayed on or under the tongue.

Oral administration is now also possible, by means of extended-release tablets or capsules.

Nitroglycerin is injected intravenously for prophylaxis and long-term treatment of angina pectoris, control of blood pressure during surgery or creation of controlled hypotension during surgery, and as an adjunct in the treatment of congestive heart failure.

An alternative to sublingual administration of nitroglycerin is application in an ointment to a hairless site on the body surface. Rotation of sites helps eliminate minor skin irritation which is a common problem. The drug is applied by using a manufacturer-supplied measuring applicator paper. A measured amount of ointment is squeezed onto the paper (never directly on the skin) in a thin uniform layer and the paper is placed on the site. The paper is then covered with plastic wrap and held in place with tape or an elastic bandage.

The usual dosage is a 1- to 2-inch strip, but 5-inch strips are also available. Most patients need several applications per day. The area is cleansed of any remaining ointment and a new site chosen when the next dose is due. Patients who are to use the nitroglycerin ointment at home must be given detailed instructions in its use and should be aware of its expected results and local and systemic side effects.

Nitroglycerin is also available as a transdermal patch.

nitroglycerin

Minitran, Nitrek, Nitro-Dur, Nitroject, Nitrolingual, Nitromist, Nitronal (UK), Nitroquick, Nitrostat

Pharmacologic class: Nitrate

Therapeutic class: Antianginal

Pregnancy risk category C

Action

Inhibits calcium transport into myocardial and vascular smooth muscle cells, suppressing contractions. Dilates main coronary arteries and arterioles, inhibits coronary artery spasm, increases oxygen delivery to heart, and reduces frequency and severity of angina attacks.

Availability

Capsules (extended-release): 2.5 mg, 6.5 mg, 9 mg

Injection: 0.5 mg/ml, 5 mg/ml

Ointment (transdermal): 2%

Solution for injection: 25 mg/250 ml, 50 mg/250 ml, 50 mg/500 ml, 100 mg/250 ml, 200 mg/500 ml

Spray (translingual): 0.4 mg/spray in 14.5-g canister (200 doses)

Tablets (buccal, extended-release): 1 mg, 2 mg, 3 mg, 5 mg

Tablets (extended-release): 2.6 mg, 6.5 mg, 9 mg

Tablets (sublingual): 0.3 mg, 0.4 mg, 0.6 mg

Transdermal system (patch): 0.1 mg/hour, 0.2 mg/hour, 0.3 mg/hour, 0.4 mg/hour, 0.6 mg/hour, 0.8 mg/hour

Indications and dosages

Management and prophylaxis of angina pectoris

Adults: For acute angina attack, 0.3 to 0.6 mg S.L., repeated q 5 minutes for 15 minutes p.r.n.; or one to two trans-lingual sprays, repeated q 5 minutes for 15 minutes p.r.n. For long-term or prophylactic use, 1-mg extended-release buccal tablet q 5 hours, with dosage and frequency increased p.r.n.; or 2.5 to 9 mg (extended-release tablets) P.O. q 8 to 12 hours; or 1.3 to 6.5 mg (extended-release capsules) P.O. q 8 to 12 hours.

Hypertension during surgery; adjunct in heart failure

Adults: 5 mcg/minute I.V., increased by 5 mcg/minute q 3 to 5 minutes up to 20 mcg/minute, then increased by 10 to 20 mcg/minute q 3 to 5 minutes (dosage based on hemodynamic parameters)

Heart failure associated with acute myocardial infarction (MI)

Adults: 12.5 to 25 mcg I.V., then a continuous infusion of 10 to 20 mcg/minute q 5 to 10 minutes; increase by 5 to 10 mcg/minute q 5 to 10 minutes as needed to a maximum of 200 mcg/minute.

Contraindications

• Hypersensitivity to drug, other organic nitrates, nitrites, or adhesives (transdermal form)

• Angle-closure glaucoma

• Orthostatic hypotension

• Hypotension or uncorrected hypovolemia (I.V. form)

• Early MI (S.L. form)

• Increased intracranial pressure (as from head trauma or cerebral hemorrhage)

• Severe anemia

• Pericardial tamponade or constrictive pericarditis

• Concurrent sildenafil therapy

Precautions

Use cautiously in:

• severe renal or hepatic impairment, glaucoma, hypertrophic cardiomyopathy

• hypovolemia, normal or decreased pulmonary capillary wedge pressure (with I.V. use)

• alcohol intolerance (with large I.V. doses)

• pregnant or breastfeeding patients

• children (safety not established).

Administration

• Administer tablets and capsules with water. Don't crush, break, or let patient chew them.

• For S.L. use, administer under tongue or in buccal pouch; instruct patient not to swallow tablet. For acute angina, give at pain onset. For angina prophylaxis, give before activities that may cause anginal pain.

• For translingual use, spray directly onto oral mucosa. Don't let patient inhale spray. Give at pain onset and as needed prophylactically before activities that trigger angina.

• For transdermal use, apply system to skin site with little hair and movement. Don't apply to distal extremities. Rotate application sites to avoid irritation and sensitization.

• Apply transdermal ointment to skin by spreading prescribed amount over 6″ × 6″ area (using an applicator, not your fingers). Cover area with plastic wrap and tape. Rotate sites to reduce risk of irritation and inflammation.

Know that solution for injection is a concentrate. Dilute with dextrose 5% in water or normal saline solution before giving by I.V. infusion.

Don't mix solution for injection with other drugs, and don't give by direct I.V. injection.

• Be aware that solution for injection is affected by type of infusion set used and that dosage is based on use of conventional PVC tubing. When using nonabsorbent tubing, reduce dosage.

• For I.V. use, administer with infusion pump. Increase dosage in increments of 5 mcg/minute every 3 to 5 minutes p.r.n. to achieve desired blood pressure response. Once achieved, reduce dosage and lengthen dosage adjustment intervals.

Don't give concurrently with sildenafil (may cause life-threatening hypotension).

Adverse reactions

CNS: dizziness, headache

CV: hypotension, syncope

Hematologic: methemoglobinemia

Skin: contact dermatitis (with transdermal or ointment use), rash, exfoliative dermatitis, flushing

Interactions

Drug-drug. Antihypertensives, beta-adrenergic blockers, calcium channel blockers, haloperidol, phenothiazines: additive hypotension

Drugs with anticholinergic properties (antihistamines, phenothiazines, tri-cyclic antidepressants): decreased absorption of lingual, S.L., or buccal nitroglycerin

Sildenafil: increased risk of potentially fatal hypotension

Drug-diagnostic tests. Cholesterol: false elevation

Methemoglobin: significant levels (with excessive doses)

Urine catecholamines, urine vanillyl-mandelic acid: increased levels

Drug-behaviors. Alcohol use, acute alcohol ingestion: increased risk of potentially fatal hypotension

Patient monitoring

With I.V. use, monitor blood pressure frequently. Titrate dosage to obtain desired results.

• With transdermal use, check for rash or skin irritation.

• Monitor patient for angina relief.

Patient teaching

• Instruct patient to place S.L. tablet directly under tongue and hold it there as it dissolves. Caution him not to chew or swallow tablet.

• Tell patient to use drug before physical activities that may cause angina.

• Instruct patient to take drug at pain onset and repeat every 5 minutes for three doses. If pain doesn't subside, advise him to seek medical attention.

• Tell patient not to chew or crush sustained-release tablets.

• Advise patient to apply correct amount of ointment using applicator. Caution him to avoid rubbing site. Instruct him to cover ointment with plastic wrap and tape it, to wash hands after placement, and to rotate sites.

• Advise patient to consult prescriber or pharmacist before changing brands of transdermal system. Different brands may have different drug concentrations.

• As appropriate, review all significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.

ni·tro·glyc·er·in

(nī'trō-glis'ĕr-in),
An explosive, yellowish, oily fluid formed by the action of sulfuric and nitric acids on glycerin; used as a vasodilator, especially in angina pectoris; generates nitric oxide.
Synonym(s): 1, 2, 3-propanetriol trinitrate, glyceryl trinitrate, trinitroglycerin

nitroglycerin

/ni·tro·glyc·er·in/ (ni″tro-glis´er-in) an antianginal, antihypertensive, and vasodilator used for the prophylaxis and treatment of angina pectoris, the treatment of congestive heart failure and myocardial infarction, and blood pressure control or controlled hypotension during surgery.

nitroglycerin

also

nitroglycerine

(nī′trō-glĭs′ər-ĭn, -trə-)
n.
A thick, pale yellow liquid, C3H5N3O9, that is explosive on concussion or exposure to sudden heat. It is used in the production of dynamite and blasting gelatin and as a vasodilator in medicine.

nitroglycerin (nitr)

[-glis′ərin]
a potent smooth muscle relaxant and vasodilator used in transdermal patches and in a paste as well as in oral and sublingual tablets. Also called glyceryl trinitrate.
indications It is prescribed for the prevention or relief of angina pectoris. There are recommended limits to the amount of nitroglycerin use before calling for emergency assistance (no more than 3 sublingual tablets at 5-minute intervals). The drug should not be used continuously, because tolerance develops within 24 to 48 hrs. Nitroglycerin is also used to treat pulmonary hypertension, to help treat congestive heart failure following acute myocardial infarction, and to treat hypertensive emergencies during cardiovascular surgery.
contraindications Head trauma, severe anemia, narrow-angle glaucoma, and known hypersensitivity to this drug or other organic nitrates prohibit its use. It should not be used by patients taking sildenafil or similar agents for treating erectile dysfunction.
adverse effects Among the most serious adverse effects are hypotension, flushing, headache, and syncope.

nitroglycerin

Cardiology Glycerol trinitrate An organic nitrate that is a short-acting agent for treating anginal pain and CHF Side effects Headache, tachycardia, nausea, hypotension; other organic nitrates–eg, ethylene nitrate, trinitrotoluene–TNT, are used to produce explosives. See Monday death.

ni·tro·glyc·er·in

(nī'trō-glis'ĕr-in)
An explosive, yellowish, oily fluid formed by the action of sulfuric and nitric acids on glycerin; used as a vasodilator, especially in angina pectoris; generates nitric oxide.
Synonym(s): 1, 2, 3-propanetriol trinitrate, glyceryl trinitrate, trinitroglycerin.
An explosive, yellowish, oily fluid formed by the action of sulfuric and nitric acids on glycerin; used as a vasodilator.

ni·tro·glyc·er·in

(nī'trō-glis'ĕr-in)
Explosive, yellowish, oily fluid formed by action of sulfuric and nitric acids on glycerin; used as a vasodilator, especially in angina pectoris.

nitroglycerin

a chemical well known as an explosive but also a venodilator and used medically, principally in the treatment of angina pectoris in humans; called also glyceryl trinitrate.