From the Guidelines
Nitroglycerin should not be administered orally, as there is no recommended oral dosage in the provided evidence. When considering the administration of nitroglycerin, it is crucial to prioritize the most effective and safe route of delivery. According to the evidence provided by 1, nitroglycerin can be administered via various routes, including sublingual tablets, spray, transdermal, and intravenous. However, there is no mention of an oral dosage for nitroglycerin. Some key points to consider when administering nitroglycerin include:
- Sublingual tablets: 0.3 to 0.6 mg up to 1.5 mg, with a duration of effect of 1 to 7 minutes
- Spray: 0.4 mg as needed, with a similar duration of effect to sublingual tablets
- Transdermal: 0.2 to 0.8 mg per hour every 12 hours, with a duration of effect of 8 to 12 hours during intermittent therapy
- Intravenous: 5 to 200 mcg per minute, with tolerance developing in 7 to 8 hours It is essential to note that other nitrates, such as isosorbide dinitrate and isosorbide mononitrate, have recommended oral dosages, but nitroglycerin does not. Therefore, nitroglycerin should only be administered via the recommended routes, and oral administration shouldn't be considered.
From the FDA Drug Label
DOSAGE & ADMINISTRATION One tablet should be dissolved under the tongue or in the buccal pouch at the first sign of an acute anginal attack. The dose may be repeated approximately every 5 minutes until relief is obtained. The frequency of administering nitroglycerin orally is every 5 minutes as needed for relief of an acute anginal attack, with a maximum of 3 tablets in a 15-minute period 2.
From the Research
Frequency of Administering Nitroglycerin Orally
The frequency of administering nitroglycerin orally is not explicitly stated in the provided studies. However, the studies discuss the importance of intermittent therapy to prevent nitrate tolerance.
- The study 3 suggests that a daily low-nitrate interval is required to prevent tolerance development, and a 12-h patch-free interval should prevent tolerance in most patients.
- The study 4 mentions that oral isosorbide-5-mononitrate, 20 mg twice a day, with the first dose administered in the morning and the second dose 7 hours later, increases exercise duration for at least 12 hours without the development of tolerance.
- The study 4 also states that isosorbide dinitrate (30 mg) prescribed at 7 AM and 1 PM does not produce tolerance to the 7 AM dose, but effects of the afternoon dose have not been evaluated.
- The study 3 recommends high single daily doses of isosorbide dinitrate or isosorbide-5-mononitrate to prevent tolerance development.
Nitrate Tolerance and Intermittent Therapy
Nitrate tolerance is a major drawback to chronic therapy, and intermittent therapy is recommended to prevent its development.
- The study 5 states that carefully designed dosing regimens and/or appropriate use of nitrate formulations (to include a nitrate-free period each day) will decrease or eliminate the problem of nitrate tolerance.
- The study 3 suggests that intermittent therapy with once-daily ingestion of high-dose sustained-release isosorbide dinitrate was successful in preventing the development of tolerance.
- The study 4 mentions that the only practical way to avoid the development of tolerance is to use intermittent daily therapy with nitrates.