Vasopressors: Uses, common brands, and safety info

In the most critical moments inside emergency rooms and intensive care units, vasopressors are often involved in the efforts to preserve life. These medicines are capable of sustaining our blood pressure during severe illnesses, such as infection, heart failure, and anaphylaxis. Their utility is curbed by the chance of significant side effects, but in the circumstances of their use, there is often little choice. One example of a vasopressor is epinephrine, which has become a popular therapeutic for the onset of a serious allergic reaction. Use this guide to review vasopressor usefulness, how they work, and their side effects.

Other vasopressors

• Dopamine

• Angiotensin II

What are vasopressors?

Vasopressors increase our blood pressure to offset the consequences of life-threatening illnesses. A drop in blood circulation can starve our vital organs of the blood flow they need, a situation referred to as shock. Shock can result in the malfunction of, and potential injury to, our brains, heart, liver, and kidneys for example.

Shock can come from a number of causes: 

• Low-volume shock results from extreme bleeding or dehydration causing low blood pressure (hypotension). 

• Cardiogenic shock is a consequence of our heart failing to pump enough to keep proper circulation to our organs. 

• Severe infections can cause septic shock, based on our body’s own inflammatory response producing chemicals that dilate our blood vessels. 

• Anaphylactic shock stems from an allergic reaction triggering our own immune system to produce chemicals that dilate our blood vessels.

Each shock scenario above is treated differently, but vasopressors may play a significant role in the medical response to all. To enable vasopressor effectiveness, intravenous fluids are frequently given in most shock cases, excluding cardiogenic shock typically. The choice of which vasopressor to use is largely determined by the type of shock present. In order to safely administer vasopressors, an intravenous catheter in a large central vein is needed to be able to carefully instill the drug.

How do vasopressors work?

Vasopressors primarily function through the adrenergic system, a portion of our nervous system that regulates blood vessel tone and heart activity. In times of emergent bodily stress, the adrenergic system is naturally engaged to produce our fight-or-flight response. 

Vasopressors can tap into the function of the adrenergic system by stimulating the receptors of its nerve cells. The alpha receptors are mostly located in blood vessel walls, and their stimulation prompts tightening of the arteries, which can raise blood pressure. Within the heart, beta receptor stimulation leads to increases in the rate and strength of the heartbeat, which can also raise blood pressure. Often, it is a matter of the vasopressor type and dose that determines which receptors’ actions predominate. Intensive care medicine providers often use hemodynamic monitoring of different blood pressures and cardiac output in order to adjust vasopressor dosing.

What are vasopressors used for?

• Anaphylaxis (allergic reaction-induced circulatory compromise)

• Septic shock (severe infection-induced)

• Hypovolemic shock (dehydration-induced)

• Hemorrhagic shock (bleeding induced)

• Cardiogenic shock (heart failure-induced)

• Neurogenic shock (brain or spinal cord injury-induced)

Types of vasopressors

Epinephrine

Also referred to as adrenaline, epinephrine stimulates both alpha and beta receptors of the adrenergic system. The combined effects of this dual receptor activity depend on dosing, but most often there is an increase in heart activity and blood pressure, which can be useful in different cases of shock. Other vasopressors are often chosen first, with the exception of anaphylaxis.

Symptoms of allergic reactions leading to anaphylaxis are swelling of the face and airways, drop in blood pressure, difficulty breathing, abdominal pain, and hives. The effect on circulation can be deadly. Epinephrine is the most important treatment and timely administration appears to be paramount. Individuals with severe allergies are encouraged to carry portable forms of epinephrine to use quickly when a reaction occurs.

The two best-known brands of portable epinephrine are Epipen and Auvi-Q. These auto-injectors automatically inject epinephrine into the muscle tissue when pressed against the outer thigh. Epipen is about the size and shape of a highlighter, and Auvi-Q is about the size and shape of a deck of cards. Epipen may be more familiar due to being on the market longer, while Auvi-Q has an automated voice that instructs on usage when the cap is removed. Generic epinephrine pens have become available.

Norepinephrine

The preferred vasopressor in septic shock is norepinephrine, according to the Surviving Sepsis Campaign—an effort to provide guidance on treating this common cause of shock. The reason is that norepinephrine’s alpha-receptor stimulation predominates, and the result is an increase in mean arterial pressure (MAP), an important measure of blood pressure in critical care.

Phenylephrine

A useful option in some settings, phenylephrine stimulates only alpha receptors leading to an increase in MAP and another measure of blood vessel tone called systemic vascular resistance (SVR). Too much of an increase in SVR can end up being counterproductive though as blood flow cannot get through arteries that are too tight. Therefore, as usual with vasopressors, dosing and monitoring are crucial.

Dopamine

Dopamine is a natural body compound that can be manufactured for medical use. It’s a great example of the importance of dosage. Low doses of dopamine cause blood vessels to dilate or relax. Moderate doses cause an increase in heart action, and high doses lead to blood vessel constriction. 

Dobutamine

Since it does not have much effect on blood pressure, dobutamine is technically not a vasopressor, but it is typically discussed within the class. Dobutamine is termed an inotrope for its ability to increase heart contraction strength. This drug functions as a beta-agonist, increasing heart activity while relaxing blood vessels. With our heart pumping out more and the SVR reduced, the MAP stays about the same. Dobutamine’s utility is mainly in cardiogenic shock from heart failure.

Vasopressin

Vasopressin is a natural body hormone, also referred to as antidiuretic hormone, that can be synthesized and used as a therapeutic infusion. It leads to fluid retention and also stimulates receptors within blood vessels to cause blood pressure to increase. 

Vasopressin infusions are typically second-line medications for some types of shock, such as septic shock if norepinephrine alone is not adequate or anaphylactic shock if epinephrine alone is inadequate. The increase in MAP results from stimulation of vasopressin receptors in arteries.

Angiotensin II

Another synthetic version of a compound native to our bodies, angiotensin II can be used to increase blood pressure in shock. Clinical trials have taken place using it in septic shock.

Who can take vasopressors?

The pressing need to respond to shock quickly means that the benefits of vasopressors outweigh their risks for most people. Certain vasopressors may best be avoided in certain cases. For example, dopamine may be avoided in the setting of cardiogenic shock based on a randomized controlled trial showing more heart rhythm problems than with norepinephrine.

Can children take vasopressors?

Children can also experience the different varieties of shock, and they can be treated with vasopressors. Their dosing is weight-based.

Can seniors take vasopressors?

While increasing age may be associated with more underlying organ dysfunction and heightened risk of adverse effects, vasopressors are still used in the setting of shock in seniors.

Are vasopressors safe?

Recalls

• Epinephrine (2018, 2019, 2019)

• Norepinephrine (2019)

• Phenylephrine (2019, 2021)

Restrictions

A black box warning from the FDA exists for norepinephrine and dopamine regarding extravasation—leakage of medicine out of the vein it is being infused into. This may occur if the intravenous catheter is misplaced or dislodged. These vasopressors can cause local tissue damage if this occurs. For this reason, these vasopressors and others are typically infused through intravenous catheters that enter the central circulation and are more securely in place.

Anyone with allergic hypersensitivity to one of the vasopressors should not take that vasopressor. Caution with certain vasopressors is advisable for those with:

• Heart disease

• Asthma

• Kidney problems

• Migraine

• Vascular disease (impaired circulation)

• High risk for blood clotting

• The adrenal tumor pheochromocytoma

• Parkinson’s disease

• Diabetes

• Psychiatric disease

• High blood pressure (hypertension)

• Overactive thyroid

• Glaucoma

• Urinary problems

Can you take vasopressors while pregnant or breastfeeding?

While caution is often advised, the potential benefit in life-threatening states may be worth the risk. Studies fully assessing vasopressor risks in pregnancy and lactation are lacking.

Are vasopressors controlled substances?

Vasopressors are not on the DEA list of controlled substances.

Common vasopressors side effects

• Heart rate or rhythm problems (arrhythmias)

• Chest pain

• Extreme blood pressure alteration

• Brain bleeding

• Headache, sweating, or nausea

• Nausea or vomiting

• Anxiety

• Low platelets (clotting cells) or clot formation

• Shortness of breath or wheezing

• Renal impairment

• Reduced body tissue blood perfusion

How much do vasopressors cost?

Outside of the ICU or emergency room, the only use of vasopressors is the portable epinephrine auto-injectors. These injectors can cost nearly $500 apiece. The SingleCare discount card and coupons can help reduce the expense.