How do you apply nitroglycerin (NTG) paste for angina pectoris?

How to Apply Nitroglycerin Paste for Angina Pectoris

Nitroglycerin paste should be applied to the skin using the provided dose measuring applicator, spread lightly without rubbing in, and covered with plastic wrap to prevent staining, with a daily nitrate-free interval of 10-12 hours to prevent tolerance. 1

Application Procedure

• Measure the desired dosage of Nitroglycerin Ointment 2% using the dose measuring applicator provided with the tube 1
• Place the applicator on a flat surface, printed side down 1
• Squeeze the necessary amount of ointment from the tube onto the applicator 1
• Place the applicator (ointment side down) on the desired area of skin, typically the chest 1
• Spread the ointment lightly using the applicator - do not rub it into the skin 1
• Cover an area approximately the size of the dose measuring applicator (3½" by 2¼") to obtain the desired clinical effects 1
• Tape the applicator in place 1
• Cover the dose measuring applicator completely with plastic kitchen wrap to prevent staining of clothing 1

Dosing Guidelines

• Start with two daily ½ inch (7.5 mg) doses, one applied on rising in the morning and one applied six hours later 1
• The dose can be increased if tolerated but not providing adequate relief 1
• Include a daily nitrate-free interval of 10-12 hours to prevent tolerance 2, 1
• For foilpac packaging, use the entire contents as a unit dose and discard immediately after use 1

Mechanism of Action and Benefits

• Nitroglycerin acts as an endothelium-independent vasodilator with both peripheral and coronary vascular effects 3
• It dilates capacitance vessels (venous bed), decreasing myocardial preload and reducing ventricular wall tension 3
• These effects reduce myocardial oxygen demand while promoting subendocardial perfusion 3
• Nitroglycerin also dilates coronary arteries and improves collateral flow to ischemic regions 3

Side Effects and Precautions

• Common side effects include headache (dose-dependent), faintness, flushing, and dizziness 1
• Postural hypotension may occur, especially when suddenly rising from a lying position 1
• If significant side effects occur, discontinue therapy and notify a physician 1
• Nitroglycerin is contraindicated after the use of sildenafil within 24 hours or tadalafil within 48 hours due to risk of severe hypotension 3

Important Considerations for Long-Term Use

• Continuous application of nitroglycerin patches or ointment leads to tolerance within 24 hours 4, 5
• To prevent tolerance, remove the paste at night to provide a nitrate-free interval of 10-12 hours 2, 1
• Store nitroglycerin ointment at 20°-25°C (68°-77°F) 1
• Keep tube tightly closed when not in use 1

Monitoring Effectiveness

• Short-acting nitrate consumption is a simple measure of treatment effectiveness with long-acting nitrates 3
• If symptoms persist despite optimal dosing of nitroglycerin paste, additional anti-anginal medications may be needed 3
• An attack of angina that does not respond to short-acting nitroglycerin should be regarded as a possible myocardial infarction 3