Final answer:
Nitroglycerine is administered sublingually for rapid relief of chest pain in acute cardiac events, with its administration starting upon onset of symptoms and ending based on the patient's response or need for further intervention.
Step-by-step explanation:
The two endpoints to the administration of nitroglycerine involve its initiation for acute relief and the consideration of its duration of effect or need for additional dosing. Initially, nitroglycerin is administered sublingually (under the tongue) during an acute episode of chest pain or myocardial infarction (MI) for its rapid absorption and quick onset of action. This form of administration leverages the compound's ability to release nitric oxide, a potent vasodilator, enhancing blood flow and oxygen delivery to cardiac muscle. It's essential to monitor the patient's response to the initial dose to decide on subsequent doses or transition to other therapeutic interventions if necessary, which marks the endpoint of its use.