What is the recommended sublingual dosing of nitroglycerine for angina pectoris?

Sublingual Nitroglycerin Dosing for Angina Pectoris

The recommended sublingual dosing of nitroglycerin for angina pectoris is 0.3 to 0.6 mg (up to a maximum of 1.5 mg), with doses taken 5 minutes apart for a maximum of 3 tablets in a 15-minute period. 1, 2

Dosing Protocol for Acute Angina

• Initial dose: 0.3-0.6 mg sublingual tablet dissolved under the tongue at the first sign of an anginal attack 1, 2
• Timing between doses: Wait approximately 5 minutes between doses 3, 2
• Maximum dosing: Up to 3 tablets in a 15-minute period 3, 2
• When to seek medical attention: If pain persists after 3 tablets in 15 minutes, prompt medical attention is recommended 2

Administration Technique

• Patient should be seated when taking nitroglycerin (to prevent falls from potential hypotension) 2
• Place tablet under the tongue until fully dissolved 2
• Do not chew, crush, or swallow the tablet 2
• Avoid eating, drinking, smoking, or using chewing tobacco while the tablet is dissolving 2

Prophylactic Use

• For prevention of anticipated angina attacks, take one tablet 5-10 minutes before engaging in activities that might precipitate an attack 1, 2
• Alternative formulations include nitroglycerin spray (0.4 mg per spray) which can be used in the same dosing pattern 1

Important Precautions

• Contraindications:

  • Use of phosphodiesterase-5 inhibitors: Do not use nitroglycerin within 24 hours of sildenafil or vardenafil, or within 48 hours of tadalafil 1, 3
  • Hypotension (systolic BP <90 mmHg or 30 mmHg below baseline) 3
  • Severe anemia 2
  • Increased intracranial pressure 2
  • Right ventricular infarction 3
  • Severe aortic stenosis 3

• Common side effects:

  • Headache (especially with initial use) 2
  • Dizziness and lightheadedness 2
  • Flushing of the face 2
  • Mild stinging sensation under the tongue 2

Storage and Practical Considerations

• Keep nitroglycerin tablets in their original container 2
• Store in multiple locations where angina attacks might occur (bedroom, office, etc.) 2
• Carry in a jacket or coat pocket (not shirt or trouser pocket) or purse 2

Tolerance Considerations

• Continuous nitrate administration can lead to tolerance 1
• A nitrate-free interval of 10-14 hours is recommended to prevent tolerance when using long-acting nitrate formulations 3

Clinical Pearls

• Sublingual nitroglycerin begins to work within 1-3 minutes with effects lasting 5-7 minutes 1
• If symptoms are unimproved or worsening 5 minutes after the first dose, consider seeking immediate medical attention 3
• An angina attack that does not respond to short-acting nitroglycerin should be considered as a possible myocardial infarction 3

By following this dosing protocol, patients can effectively manage acute angina episodes while minimizing risks associated with nitroglycerin use.