How Do Dopamine Agonists Work?

Dopamine agonists are a class of drugs used for in-hospital, short-term (up to 48 hours) management of severe hypertension (high blood pressure) in an emergency situation when rapid, but quickly reversible, emergency reduction of blood pressure is indicated including malignant hypertension with worsening end-organ function. The only drug that belongs to this class is “fenoldopam,” a rapid-acting vasodilator that works by lowering the blood pressure through arteriolar vasodilation (widening of the arteries and large blood vessels). 

Dopamine is a type of neurotransmitter (a chemical messenger) used by the nervous system to send messages between the nerve cells. It is produced in the brain through a two-step process: first, it changes the amino acid “tyrosine” to a substance called “dopa” and then into “dopamine.” It affects many parts of behavioral and physical functions, such as:

• Learning
• Motivation
• Heart rate
• Blood vessel function
• Kidney function
• Lactation
• Sleep
• Mood
• Attention
• Control of nausea and vomiting
• Pain processing
• Movement

Changes in levels of this brain chemical can alter our behavior, movement, mood, memory, and many other reactions.

Dopamine agonists are administered as a continuous intravenous infusion until the blood pressure is normal again.

Dopamine agonists work in the following ways:

• Dopamine agonists are medications that work by imitating the actions of dopamine by activating the dopamine receptors.
• There are two major groups of dopamine receptors, D1 and D2, with subgroups in them that are responsible for many behavioral, hormonal, and muscle-related effects in the body.
• They act as a rapid-acting vasodilator and an agonist for D1-like dopamine receptor by binding with moderate affinity to α2-adrenoceptors.
• This binding helps in copying the effects of the neurotransmitter to improve disorders that occur from low levels of dopamine.

Dopamine agonists are used to treat severe/malignant hypertension and hypertensive emergencies.

Some of the common side effects include:

• Nausea
• Vomiting
• Headache
• Flushing (warmth, redness, or tingly feeling, particularly in the face and neck)

Other rare side effects include:

• Hypotension (low blood pressure)
• Fast heartbeat
• Hypokalemia (low blood potassium level)
• Dizziness (feeling faint, weak, or unsteady)
• Serum creatinine raised

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of dopamine agonists include:

• Corlopam
• Fenoldopam