Vasopressors are compounds that cause the blood vessels to constrict, which, in turn, causes blood pressure to rise. A number of compounds can have this effect, ranging from pharmaceuticals that are used on patients in certain situations to recreational drugs that have a vasoconstrictive effect. Such compounds need to be used carefully, because they can cause blood pressure to rise dangerously high, putting someone at risk of medical complications.
In the world of medicine, vasopressors can be tremendously useful. These compounds are used to manage patients in shock, to address dangerous drops in blood pressure, and to manage patients in the operating room. In the operating room, they are typically administered by the anesthesiologist, as this member of the surgical team is responsible for keeping the patient as stable as possible. Anesthesiologists receive highly specialized training in the kinds of drugs they can administer to patients and the situations in which the need for such drugs might arise.
Vasopressors can also be used with compounds known as inotropes. Inotropes are compounds that influence muscle contraction, with some causing muscles to contract, while others force muscles to relax. In medicine, those that stimulate contraction of the heart muscle are used to increase the force of cardiac contractions so that a patient's blood pressure will rise. Managing blood pressure can be especially important in the operating room, as the surgeon does not want the patient to die during the procedure as the body struggles to cope with the tremendous physical toll caused by surgery.
These drugs must be administered with care. In a hospital setting, dosages are carefully calculated for a given patient, taking into account the specific medication being used. The medical professional thinks about how long the medication acts on the body, the recommended dosages, and the desired effect. Anesthesiologists need to be very skilled at math and at thinking on the fly so that they can be ready to intervene in any number of emergencies that can come up while a patient is under general anesthesia on the operating table.
Outside of medicine, a wide variety of things act as vasopressors. Caffeine, for example, is well known for being a vasoconstrictor. The body also makes its own, in the form of things like epinephrine. These compounds in the body act on the autonomic nervous system, just like compounds that are introduced to the body, and many play a role in the “fight or flight” response to stress.