Catecholamines vs vasopressors: Differences, similarities, and which one is better for you

Differences | List of catecholamines and vasopressors | Conditions treated | Effectiveness | Side Effects | Interactions | Warnings | Cost and Coverage | FAQs

Catecholamine medications are a group of drugs designed to mimic your body’s naturally produced catecholamine neurotransmitters. These catecholamines are produced in the brain, nerve tissues, and the adrenal glands located just above the kidneys. They each serve different functions in your body’s response to stress, also referred to as the “fight or flight” syndrome. Synthetically produced catecholamine drugs work to mimic the desired effects of these catecholamine neurotransmitters when the body needs them. 

Vasopressors are a group of drugs specifically used to increase your body’s blood pressure when life-threatening conditions, such as shock or anaphylaxis, threaten your organs with a drop in blood pressure and circulation. Vasopressor drugs are a specific type of catecholamine drug used for the specific purpose of raising blood pressure. However, there are catecholamine drugs that are not used as vasopressors. We will discuss the specific differences in use, side effects, and other key differences between these medications.

What are the main differences between catecholamines and vasopressors?

Vasopressors are a type of catecholamine drug, but not all catecholamine drugs are used as vasopressors. 

Catecholamine drugs are designed to mimic your body’s naturally occurring catecholamines: adrenaline, noradrenaline, and dopamine. Adrenaline, also known as epinephrine, is released during times of stress primarily from the adrenal medulla (adrenal gland), a part of your endocrine system. The release of adrenaline causes increased blood flow to the muscles, heart, and lungs. Noradrenaline, also referred to as norepinephrine, is primarily produced in the nerves. Dopamine is found throughout the nervous system and plays a role in emotions, memory, and movement. The four catecholamine active drug ingredients available in various dosage forms are dobutamine, dopamine, epinephrine, and isoproterenol.

Catecholamine drugs are active on the body’s alpha and beta-adrenergic receptors. Alpha receptors primarily play a role in the constriction of smooth muscle and blood vessels. Stimulation of beta receptors of the heart, also known as beta-1 receptors, causes the heart to beat faster and more forcefully. In contrast, beta-2 receptors, located in the lungs and throughout the body, cause relaxation and dilation of the smooth muscle located in your veins and airways. 

The affinity of catecholamine drugs for these receptors is dose-dependent. For instance, epinephrine has a high affinity for beta-1 receptors and moderate affinity for beta-2 receptors at low doses but has a high affinity for alpha receptors and moderate affinity for beta-1 and beta-2 receptors at high doses. This explains why epinephrine, at relatively low doses such as that in Primatene Mist, is effective in asthma because it leads to a relaxation of the smooth muscle of the airways, making it easier to move air to the lungs to provide oxygen to the blood.

At high doses, epinephrine, in the form of a subcutaneous injection like EpiPen, is used in conditions such as anaphylactic shock. Anaphylactic shock is an extreme allergic reaction to the body. It causes a drastic drop in blood pressure and a constriction of the airways. Because epinephrine at high doses affects both alpha and beta receptors, it works to constrict blood vessels to keep blood pressure up as well as relax airways to allow easier breathing.

Vasopressor medications are also synthetic versions of your body’s natural vasopressor neurotransmitters. In addition to adrenaline, noradrenaline, and dopamine, your body also uses the angiotensin II transmitter to cause the release of the hormone vasopressin to increase blood pressure when needed. In clinical practice, epinephrine is the primary drug utilized as a vasopressor. Recall that epinephrine at high doses affects both alpha and beta receptors. 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. 

The appropriate use of these medications is determined by administration method and dosing. 

Other catecholamines:

• Medihaler-Iso (isoproterenol)
• Levophed (norepinephrine)
• Twinject (epinephrine)
• Medihaler-Epi (epinephrine)
• Isuprel (isoproterenol)
• EPIsnap (epinephrine)
• Dobutrex (dobutamine)
• Bronkaid Mist (epinephrine)
• Adrenaclick (epinephrine)

Other vasopressors:

• Twinject (epinephrine)
• EPIsnap (epinephrine)
• Adrenaclick (epinephrine)

Conditions treated by catecholamines and vasopressors

Catecholamine drugs may be used in a variety of indications related to airway constriction, cardiac function, and even ophthalmic disorders. These include asthma, croup, anaphylaxis, heart failure, and shock. Specifically, vasopressor-type catecholamines are utilized when your body is in shock. Shock is a condition where the body’s circulation has dropped, and your critical organs are no longer receiving the blood they need to provide oxygen essential for their function. Shock can be induced by a variety of causes including infection, dehydration, heart failure, brain or spinal cord injury, or massive blood loss. 

Are catecholamines or vasopressors more effective?

The fact is that both classes of medications are highly effective for their intended uses. These are life-saving medications which provide support to our cardiac and respiratory systems to keep us alive. Their effectiveness is dependent upon using the appropriate dosage form at the correct dose. A good example is the use of epinephrine at low doses via an inhaler to cause a relaxation of the smooth muscle of the airways, making it easier to breathe. At high doses, epinephrine, in the form of a subcutaneous injection like EpiPen, is a vasopressor used in conditions such as anaphylactic shock because it increases the forcefulness of the heart beat and causes vasoconstriction, which raises the blood pressure. When referring to catecholamines and vasopressors, it is not a matter of one class being superior, but more importantly, that they are used appropriately for the indication you wish to treat. Only a medical professional can decide which ingredient, delivery method, and  dose is appropriate for you.

Common side effects of catecholamine and vasopressors

The side effects of catecholamines and vasopressors are mostly derived from their actions within the central nervous system during life-threatening situations. While some side effects are serious in nature, precedent is given to life-saving actions of these drugs. The following is a list of the most common side effects of these medications:

• Anxiety
• Restlessness
• Tremor
• Weakness
• Dizziness
• Sweating
• Palpitations
• Pallor
• Nausea
• Vomiting
• Headache
• Respiratory difficulties
• Arrhythmias
• Rapid rise in blood pressure
• Angina
• Tissue necrosis
• Tachycardia
• Coldness

Drug interactions of catecholamines vs. vasopressors

Certain classes of drugs can increase the accumulation of your body’s natural catecholamines. One such example are monoamine oxidase inhibitors which can increase catecholamine levels in the brain. These include Marplan (isocarboxazid), Nardil (phenelzine), and Emsam (selegiline). Another example are tricyclic antidepressants such as Pamelor (nortriptyline) and Elavil (amitriptyline), which will prolong the hypertensive effects of catecholamines and vasopressors. These interactions are especially concerning in patients using a catecholamine drug for an indication not related to the need to raise blood pressure.

The use of digoxin with catecholamines and vasopressors increases the chance of a cardiac arrhythmia occurring. However, in a life and death situation, you may still administer a vasopressor while monitoring for arrhythmias.

Antihypertensive drugs generally decrease the response to catecholamine and vasopressor drugs. Antihypertensive drugs include various classes of drugs which act on different components of the circulatory system to lower blood pressure. 

Vasodilators, such as Nitrostat (nitroglycerin) will work against the actions of vasopressors. In an emergency situation, it is important to know if a patient has had a recent dose of nitroglycerin so that emergency response teams can consider this when dosing. 

Make sure to tell your physician all of the medications you are taking. In a life or death scenario, having a list of your medications that is easy to identify may be critical to saving your life.

Warnings of catecholamines and vasopressors

Patients with a known sensitivity to catecholamines or vasopressors should avoid their use unless they are in a life-threatening emergency with no other treatment options. Some dosage forms may contain a sulfur ingredient which could trigger a hypersensitivity reaction in a patient allergic to sulfur. Use in sulfa-allergic patients should be limited to life-saving measures only.

Patients with pre-existing cardiac disease such as hypertension or coronary artery disease may be at an increased risk of developing cardiac arrhythmias, myocardial ischemia, and angina pectoris. Unintended increases in blood pressure can be dangerous in patients with uncontrolled hypertension. For patients with naturally high levels of catecholamines, it may be necessary to take alpha receptor blockers, such as clonidine, to help inhibit some of the negative cardiac effects.

Vasopressors should never be injected in the extremities such as fingers, toes, nose, and genitalia. The vasoconstriction can completely cut off blood flow to these extremities causing tissue necrosis. 

Catecholamines are used in the treatment of open-angle glaucoma but can exacerbate and worsen closed-angle glaucoma. Do not treat your glaucoma condition without your doctor’s guidance.

Certain tumors and atypical cells will cause an increase in the body’s catecholamine levels. A pheochromocytoma is a tumor that can develop in certain cells, known as chromaffin cells, inside the adrenal gland. This tumor causes the secretion of too much adrenaline and noradrenaline, even when you are not in a stressful situation. This can cause an unwarranted increase in blood pressure, heart rate, heavy sweating, tremors, weight loss, or panic attack symptoms. Paragangliomas are another similar type of tumor that happens in chromaffin cells in other parts of the body and have similar effects on your body. 

Neuroblastomas are a type of cancer that also causes the release of too many catecholamines. Your body breaks down catecholamines into metabolites, and the two most common metabolites are homovanillic acid (HVA) and vanillylmandelic acid (VMA).  These diagnoses of these disorders include a urine test or blood test to look at the levels of catecholamines and their metabolites in your body. These test results are only one component of the diagnosis. Catecholamine drugs will exacerbate the symptoms of these rare tumors and cancer due to the high levels of catecholamines already present, and their use in these patients could be life-threatening.

Coverage and cost of catecholamines vs. vasopressors

The most accessible and user-friendly version of injectable epinephrine are auto-injectors. These are designed as pre-filled auto-injector pens ready to give a life-saving dose within seconds with minimal chance for error. You may be familiar with the brand-name Epipen, but there are also others. Insurance coverage for these pens can vary greatly between plans, and your out-of-pocket responsibility can be quite significant even with insurance coverage in some instances. Keep in mind that these auto-injectors typically only have a shelf-life of one year or so, and must be replaced before they expire, even if you haven’t used it. SingleCare offers savings coupons for EpiPen and other brand-name and generic epinephrine injectors. The following table provides the average cash price for some of the auto-injectors available on the market. Follow the link to each SingleCare coupon to see how much you may be able to save. In some instances, the SingleCare price may be lower than your insurance price. 

Other catecholamine drugs such as Primatene Mist are available without a prescription over-the-counter. However, if your doctor prescribes Primatene Mist, you can utilize a SingleCare coupon to save money on your cost

Frequently asked questions about catecholamines and vasopressors

What are catecholamines?

Catecholamine medications are designed to mimic natural neurotransmitters released by the body in response to both physical and emotional stress.  There are four catecholamine drugs that come in various dosage forms: dobutamine, dopamine, epinephrine, and isoproterenol.

What are vasopressors?

Vasopressor drugs are a specific type of catecholamine drug used for the specific purpose of raising blood pressure. Epinephrine is the most commonly used vasopressor.

Are catecholamines and vasopressors the same?

Vasopressor drugs are included in the broader catecholamine class, however, not all catecholamine drugs are used as vasopressors. The indication, or intended use of the drug, will determine the dosage and route of administration of the drug.

Can I use catecholamines or vasopressors while pregnant?

Catecholamines and vasopressors can be used in life-saving situations such as the mother going into anaphylactic shock or septic shock. However, it can cause decreased blood flow to the uterus and fetal anoxia (lack of oxygen to the fetus). The Food and Drug Administration (FDA) has not assigned the catecholamines a pregnancy category. There is no scientific information on the presence of drugs such as epinephrine in breast milk. Use should be limited to life-threatening conditions only.

Can I use catecholamines or vasopressors with alcohol?

There is no specific interaction with alcohol, however alcohol generally has a hypotensive effect on the body which may antagonize the desired effects of catecholamines and vasopressors.