What are the similarities and differences between epinephrine and norepinephrine?

Epinephrine and norepinephrine possess certain distinctions while also sharing similarities, primarily in their effects on the cardiovascular system. Norepinephrine enhances myocardial contractility, increasing cardiac output and accelerating heart rate. In contrast, epinephrine primarily acts by binding to myocardial cells, resulting in an increase in heart rate, making it a clinically useful drug for emergency cardiac resuscitation.

Both epinephrine and norepinephrine exert both common and specific effects on the heart and vasculature. Upon binding to receptors on the myocardial cell membrane, epinephrine causes an increase in heart rate, myocardial contractility, and cardiac output, making it a commonly used drug for cardiac resuscitation. Norepinephrine also significantly enhances myocardial contractility, increases heart rate, and elevates cardiac output. Additionally, it strongly constricts small arteries other than the coronary arteries, leading to a significant increase in peripheral resistance and blood pressure, thus often used clinically as a vasopressor.

1. In cases of cardiac arrest, epinephrine hydrochloride can be used to strengthen the heart. Its primary manifestations are the restoration of spontaneous heartbeat and an increase in blood pressure.

2. Epinephrine is also used in the treatment of severe asthma, helping to alleviate its symptoms.

3. Epinephrine can also be combined with local anesthetics such as lidocaine to enhance the effects of local anesthesia.

4. Additionally, epinephrine can be used in the treatment of allergic shock caused by penicillin.