Nitro-Dur

Name: Nitro-Dur

Nitro-Dur Overview

Nitro-Dur is a prescription medication used to prevent episodes of angina (sudden chest pain). Nitro-Dur belongs to a group of drugs called nitrates. These work by relaxing (widening) blood vessels, which makes it easier for the heart to pump blood.

Nitro-Dur is available as an extended-release transdermal film. It is applied to the skin once daily and worn for 12 to 14 hours and then removed.

Common side effects of Nitro-Dur include headache, dizziness, decreased blood pressure, and increased chest pain.

Nitro-Dur may cause dizziness. Do not drive or operate heavy machinery until you know how Nitro-Dur affects you.

Nitro-Dur Dosage

Take this medication exactly as prescribed by yoru doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

  • the condition being treated
  • how you respond to this medication

The recommended dose of Nitro-Dur for the prevention of angina is 0.2 to 0.4 mg/hr for 12 to 14 hours daily.

Nitro-Dur Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common
  • Lightheadedness
Less common
  • Arm, back, or jaw pain
  • blurred vision
  • chest pain or discomfort
  • chest tightness or heaviness
  • confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • fast or irregular heartbeat
  • nausea
  • sweating
  • unusual tiredness or weakness
Rare
  • Bluish-colored lips, fingernails, or palms
  • dark urine
  • difficulty with breathing
  • fever
  • headache
  • pale skin
  • rapid heart rate
  • sore throat
  • unusual bleeding or bruising
Incidence not known
  • Blistering, burning, crusting, dryness, or flaking of the skin
  • cough
  • difficulty with swallowing
  • hives or rash
  • itching, scaling, severe redness, soreness, or swelling of the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose
  • Blurred or loss of vision
  • bulging soft spot on the head of an infant
  • change in consciousness
  • change in the ability to see colors, especially blue or yellow
  • cold, clammy skin
  • disturbed color perception
  • double vision
  • feeling of constant movement of self or surroundings
  • halos around lights
  • headache, severe and throbbing
  • loss of consciousness
  • night blindness
  • overbright appearance of lights
  • paralysis
  • sensation of spinning
  • tunnel vision

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Rare
  • Burning, itching, redness, skin rash, swelling, or soreness at the application site

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Uses of Nitro-Dur

  • It is used to prevent chest pain or pressure.
  • It may be given to you for other reasons. Talk with the doctor.

Nitro-Dur Description

Nitroglycerin is 1,2,3-propanetriol trinitrate, an organic nitrate whose structural formula is:

and whose molecular weight is 227.09. The organic nitrates are vasodilators, active on both arteries and veins.

The Nitro-Dur® (nitroglycerin) Transdermal Infusion System is a flat unit designed to provide continuous controlled release of nitroglycerin through intact skin. The rate of release of nitroglycerin is linearly dependent upon the area of the applied system; each cm2 of applied system delivers approximately 0.02 mg of nitroglycerin per hour. Thus, the 5-, 10-, 15-, 20-, 30-, and 40-cm2 systems deliver approximately 0.1, 0.2, 0.3, 0.4, 0.6, and 0.8 mg of nitroglycerin per hour, respectively.

The remainder of the nitroglycerin in each system serves as a reservoir and is not delivered in normal use. After 12 hours, for example, each system has delivered approximately 6% of its original content of nitroglycerin.

The Nitro-Dur transdermal system contains nitroglycerin in acrylic-based polymer adhesives with a resinous cross-linking agent to provide a continuous source of active ingredient. Each unit is sealed in a paper polyethylene-foil pouch.

Cross section of the system.

Indications and Usage for Nitro-Dur

Transdermal nitroglycerin is indicated for the prevention of angina pectoris due to coronary artery disease. The onset of action of transdermal nitroglycerin is not sufficiently rapid for this product to be useful in aborting an acute attack.

Warnings

Amplification of the vasodilatory effects of the Nitro-Dur patch by phosphodiesterase inhibitors, eg, sildenafil can result in severe hypotension. The time course and dose dependence of this interaction have not been studied. Appropriate supportive care has not been studied, but it seems reasonable to treat this as a nitrate overdose, with elevation of the extremities and with central volume expansion.

The benefits of transdermal nitroglycerin in patients with acute myocardial infarction or congestive heart failure have not been established. If one elects to use nitroglycerin in these conditions, careful clinical or hemodynamic monitoring must be used to avoid the hazards of hypotension and tachycardia.

A cardioverter/defibrillator should not be discharged through a paddle electrode that overlies a Nitro-Dur patch. The arcing that may be seen in this situation is harmless in itself, but it may be associated with local current concentration that can cause damage to the paddles and burns to the patient.

Overdosage

Hemodynamic Effects

Nitroglycerin toxicity is generally mild. The estimated adult oral lethal dose of nitroglycerin is 200 mg to 1,200 mg. Infants may be more susceptible to toxicity from nitroglycerin. Consultation with a poison center should be considered.

Laboratory determinations of serum levels of nitroglycerin and its metabolites are not widely available, and such determinations have, in any event, no established role in the management of nitroglycerin overdose.

No data are available to suggest physiological maneuvers (eg, maneuvers to change the pH of the urine) that might accelerate elimination of nitroglycerin and its active metabolites. Similarly, it is not known which – if any – of these substances can usefully be removed from the body by hemodialysis.

No specific antagonist to the vasodilator effects of nitroglycerin is known, and no intervention has been subject to controlled study as a therapy of nitroglycerin overdose. Because the hypotension associated with nitroglycerin overdose is the result of venodilatation and arterial hypovolemia, prudent therapy in this situation should be directed toward increase in central fluid volume. Passive elevation of the patient's legs may be sufficient, but intravenous infusion of normal saline or similar fluid may also be necessary.

The use of epinephrine or other arterial vasoconstrictors in this setting is likely to do more harm than good.

In patients with renal disease or congestive heart failure, therapy resulting in central volume expansion is not without hazard. Treatment of nitroglycerin overdose in these patients may be subtle and difficult, and invasive monitoring may be required.

Methemoglobinemia

Nitrate ions liberated during metabolism of nitroglycerin can oxidize hemoglobin into methemoglobin. Even in patients totally without cytochrome b5 reductase activity, however, and even assuming that the nitrate moieties of nitroglycerin are quantitatively applied to oxidation of hemoglobin, about 1 mg/kg of nitroglycerin should be required before any of these patients manifests clinically significant (310%) methemoglobinemia. In patients with normal reductase function, significant production of methemoglobin should require even larger doses of nitroglycerin. In one study in which 36 patients received 2 to 4 weeks of continuous nitroglycerin therapy at 3.1 to 4.4 mg/hr, the average methemoglobin level measured was 0.2%; this was comparable to that observed in parallel patients who received placebo.

Notwithstanding these observations, there are case reports of significant methemoglobinemia in association with moderate overdoses of organic nitrates. None of the affected patients had been thought to be unusually susceptible.

Methemoglobin levels are available from most clinical laboratories. The diagnosis should be suspected in patients who exhibit signs of impaired oxygen delivery despite adequate cardiac output and adequate arterial PO2. Classically, methemoglobinemic blood is described as chocolate brown, without color change on exposure to air.

Methemoglobinemia should be treated with methylene blue if the patient develops cardiac or CNS effects of hypoxia. The initial dose is 1 to 2 mg/kg infused intravenously over 5 minutes. Repeat methemoglobin levels should be obtained 30 minutes later and a repeat dose of 0.5 to 1.0 mg/kg may be used if the level remains elevated and the patient is still symptomatic. Relative contraindications for methylene blue include known NADH methemoglobin reductase deficiency or G-6-PD deficiency. Infants under the age of 4 months may not respond to methylene blue due to immature NADH methemoglobin reductase. Exchange transfusion has been used successfully in critically ill patients when methemoglobinemia is refractory to treatment.

PRINCIPAL DISPLAY PANEL - 60 mg Pouch Box

NDC 0085-3315-30
Contents: 30 units

Nitro-Dur®
(nitroglycerin)
Transdermal Infusion System

0.3
mg/hr
(15 cm2)

Each unit contains 60 mg of
nitroglycerin in acrylic-based
polymer adhesives with a
resinous cross-linking agent.

Rated release in vivo 0.3 mg/hr.

Rx only

PRINCIPAL DISPLAY PANEL - 80 mg Pouch Box

NDC 0085-3320-30
Contents: 30 units

Nitro-Dur®
(nitroglycerin)
Transdermal Infusion System

0.4
mg/hr
(20 cm2)

Each unit contains 80 mg of
nitroglycerin in acrylic-based
polymer adhesives with a
resinous cross-linking agent.

Rated release in vivo 0.4 mg/hr.

Rx only

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