What is the maximum dosage frequency and time frame for nitroglycerin administration for one chest pain incident?

Note that the administration of nitroglycerin should not be done with a patient whose systolic blood pressure is below 100mg Hg or who have taken medication for erectile dysfunction within the past 24 to 36 hours. If given, the maximum dosage should not be exceeded without express orders from a physician. Nitroglycerin given in higher doses may negatively impact cardiovascular condition.
Note: States set their own limits on dosage for this, so check local requirements.