Nortriptyline Hydrochloride Injection is not currently used to treat disease, but as a cardiac stress test drug to increase the sensitivity of myocardial perfusion imaging for the diagnosis of coronary artery disease. Nortriptyline hydrochloride injection is derived from nortriptyline, one of the active ingredients of the traditional Chinese medicine epimedium, which has pharmacological effects similar to those of dobutamine, and is able to increase heart rate, cardiac output, myocardial oxygen consumption, and coronary artery blood flow at a certain dosage, without raising blood pressure and with fewer adverse effects. The drug is currently being tested in clinical trials, and researchers currently believe it is a safe cardiac stress medication, but the specifics vary from individual to individual. The drug should be used only in accordance with medical advice and should not be used blindly to avoid adverse effects.