Nitroglycerin Dosage Forms and Strengths
Nitroglycerin is available in four primary dosage forms with the following specific strengths: sublingual tablets (0.3 mg, 0.4 mg, 0.6 mg), sublingual/oral spray (0.4 mg per spray), transdermal patches (0.2-0.8 mg/hour), and intravenous solution (typically dosed 5-200 mcg/min).1, 2, 3
Sublingual Tablets
Sublingual tablets are supplied in three strengths:
- 0.3 mg tablets - white to off-white, modified rectangle shaped, debossed with "CL" on one side and "3" on the other
- 0.4 mg tablets - white to off-white, modified rectangle shaped, debossed with "CL" on one side and "4" on the other
- 0.6 mg tablets - white to off-white, modified rectangle shaped, debossed with "CL" on one side and "6" on the other
These tablets are typically dosed as 0.3-0.6 mg up to 1.5 mg, taken every 5 minutes as needed, with a maximum of 3 doses for acute anginal episodes.1, 3 The onset of action occurs within 1-7 minutes.1, 2
Sublingual/Oral Spray
The metered spray delivers 0.4 mg of nitroglycerin per spray emission. This formulation is dosed as needed for acute symptoms, with effects similar to sublingual tablets in both onset and duration.1, 2, 4 The spray offers advantages in reliability of effect, ease of application, and high stability compared to solution forms.5
Transdermal Patches
Transdermal patches are available in delivery rates ranging from 0.2 to 0.8 mg per hour. These are applied every 12 hours to allow for a nitrate-free interval, which is critical to prevent tolerance development.1, 2 The duration of effect is 8-12 hours during intermittent therapy.1
Intravenous Formulation
Intravenous nitroglycerin is dosed from 5 to 200 mcg per minute, though prolonged infusions at 300-400 mcg/min have been used safely without increasing methemoglobin levels.1
The most recent 2025 ACC/AHA/ACEP guidelines recommend:4
- Starting dose: 10 mcg/min via continuous infusion through non-absorbing tubing
- Titration: Increase by 10 mcg/min every 3-5 minutes until symptom relief or blood pressure response
- Target: Systolic blood pressure should not fall below 90 mm Hg or drop more than 30 mm Hg from baseline
- Maximum: While no official maximum exists, 200 mcg/min is commonly used as a ceiling dose
Tolerance typically develops after 7-8 hours of continuous IV infusion.1, 2
Important Clinical Considerations
Contraindications apply across all formulations: Nitroglycerin must not be administered within 12 hours of avanafil, 24 hours of sildenafil or vardenafil, or 48 hours of tadalafil use due to risk of profound hypotension.2, 4 Avoid use when systolic blood pressure is <90 mm Hg or with marked bradycardia or tachycardia.1
Storage requirements: All sublingual formulations should be stored at 20-25°C (68-77°F) in controlled room temperature conditions.3