What Is a Dopamine Agonist?

Table of ContentsView AllTable of ContentsDopamine Agonists vs. AntagonistsTypes of Dopamine AgonistsUsesImpactPotential Pitfalls

Table of ContentsView All

View All

Table of Contents

Dopamine Agonists vs. Antagonists

Types of Dopamine Agonists

Uses

Impact

Potential Pitfalls

Close

A dopamine agonist is a type of medication that binds todopaminereceptors in the brain and mimics the actions of dopamine. Dopamine is an importantneurotransmitterthat plays a role in a variety of mental functions.

Dopamine levels can have an impact on mood, memory, and behavior. Dopamine agonists are sometimes used to treat disorders linked to problems with dopamine, includingschizophreniaandbipolar disorder.

Dopamine is one of the neurotransmitters found in the synaptic space, which is the space between neurons (nerve cells). Dopamine is released into the synaptic space from vesicles housed in the pre-synaptic neuron. These chemicals then bind to dopamine receptors in the postsynaptic neuron.

Think of this as a key and lock type of effect: Dopamine receptors are locks that open when the dopamine “key” enters the lock.

One explanation for schizophrenia is that there is too much dopamine in the synapses in certain parts of the brain. Thepositive symptomsof schizophrenia are thought to be a result of all these “extra” dopamine molecules.

Dopamine Antagonists

Some antipsychotic medications work as dopamine antagonists. They bind to the dopamine receptors, thus blocking dopamine from binding to the post-synaptic cell. And without the proper key, i.e. dopamine, the lock does not open. This prevents excess dopamine activity and helps relieve some of the symptoms of schizophrenia.

The problem with this approach is that the dopamine blockade occurs all over the brain, while the dopamine excess in schizophrenia is limited to specific parts of the brain. Further, in schizophrenia, while some parts of the brain are subject to dopamine excess, other parts are in fact experiencing a dopamine deficit.

Dopamine antagonists do not only block dopamine receptors in places where there is too much of it but also in places where there is not enough dopamine.

Dopamine antagonists are effective for positive symptoms because they block receptors in brain regions that have too much dopamine. But this is why these medications tend to also increasenegative symptoms, cognitive issues, and other side effects in patients taking them.

Dopamine Partial Agonists

A potential solution is to use partial agonists. A dopamine partial agonist is a molecule that binds to the receptor and partially activates it. Think about it as a key that sort of fits in the lock so that the door can be wriggled about but not completely opened.

The effect of a dopamine partial agonist is less than the full effect but more than a complete lack of effect, which is what happens when a receptor is completely blocked. In other words, a partial effect.

In situations when there is too little dopamine to activate all the available receptors, aripiprazole will actually bind to unoccupied receptors and mimic its effect, even if only partially. This can help add to the dopamine effect in synapses that were previously dopamine-deprived.

Depending on a person’s existing dopamine levels, a dopamine agonist medication such as aripiprazole may act as a full antagonist, a moderate antagonist, or a partial agonist.

Recap

Antipsychotic medications that act as dopamine agonists are:

The majority of second-generation (atypical) antipsychotics block the D-2 (dopamine-2) receptors but also blockserotoninreceptors. Serotonin is another neurotransmitter involved in mood.

Second-generation antipsychotics such asRisperdal (risperidone),Geodon (ziprasidone), andInvega (paliperidone)are all potent antagonists of dopamine D2 receptors, whileClozaril (clozapine)andSeroquel (quetiapine)are weak D2 antagonists.

Other Types of Dopamine AgonistsThere are also other types of dopamine agonist medications that may be prescribed to treat medical conditions linked to dopamine activity. For example, some dopamine agonist medications may be helpful in the treatment of Parkison’s disease and restless leg syndrome. Research has also found thatcannabidiol(CBD) acts as a dopamine partial agonist and may have antipsychotic effects.

Other Types of Dopamine Agonists

There are also other types of dopamine agonist medications that may be prescribed to treat medical conditions linked to dopamine activity. For example, some dopamine agonist medications may be helpful in the treatment of Parkison’s disease and restless leg syndrome. Research has also found thatcannabidiol(CBD) acts as a dopamine partial agonist and may have antipsychotic effects.

Uses of Dopamine Agonists

Because these medications modulate dopamine activity, they can be useful in the treatment of psychiatric conditions including schizophrenia and bipolar disorder. These conditions are associated with too much dopamine activity.

Excessive dopamine action can cause certain areas of the brain to become overactive, which is believed to play a role in symptoms such asdelusionsandhallucinations.

The FDA has also approved aripiprazole in the treatment of other conditions including mixed episodes of bipolar disorder, long-term treatment of bipolar disorder, adjunctive treatment of majordepression, Tourette’s syndrome, and symptoms ofirritabilityassociated with autism.

It is also sometimes prescribed off-label to treatborderline personality disorderand elevated prolactin levels that may occur when taking other antipsychotic medications.

Impact of Dopamine Agonists

Dopamine agonists may help relieve common symptoms of schizophrenia including hallucinations, delusions, and disorganized thinking. Research suggests that aripiprazole is as effective as other antipsychotic medications in the treatment of schizophrenia.

A benefit of this medication is that it is less likely to produce extrapyramidal side effects than typical antipsychotics. It is also less likely to produce metabolic changes than other atypical antipsychotic medications.

What Are Extrapyramidal Side Effects?Extrapyramidal side effectsare involuntary movements that sometimes occur when taking antipsychotic medication. They are less likely to occur with some types of medications, but all antipsychotics can potentially produce these side effects.

What Are Extrapyramidal Side Effects?

Extrapyramidal side effectsare involuntary movements that sometimes occur when taking antipsychotic medication. They are less likely to occur with some types of medications, but all antipsychotics can potentially produce these side effects.

Dopamine agonists can still have side effects and other adverse reactions. Some potential side effects include:

With aripiprazole, the risk for certain neurological adverse effects such as episodes of acute muscular rigidity (dystonia) or involuntary abnormal movement disorders (dyskinesia) is low. This can be contrasted with antipsychotics that have a high risk for these adverse effects, which are classified as typicals.

Summary

This may help relieve some psychotic symptoms such as hallucinations, delusions, and disorganized thinking. These medications are also less likely to cause extrapyramidal symptoms than other types of antipsychotics due to their mechanism of action.

5 SourcesVerywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Seeman P.Cannabidiol is a partial agonist at dopamine D2High receptors, predicting its antipsychotic clinical dose.Transl Psychiatry. 2016;6(10):e920-e920. doi:10.1038/tp.2016.195National Alliance on Mental Illness.Aripiprazole (Abilify).Ribeiro ELA, de Mendonça Lima T, Vieira MEB, Storpirtis S, Aguiar PM.Efficacy and safety of aripiprazole for the treatment of schizophrenia: an overview of systematic reviews.Eur J Clin Pharmacol. 2018;74(10):1215-1233. doi:10.1007/s00228-018-2498-1FDA.Highlights of prescribing information: Abilify.Divac N, Prostran M, Jakovcevski I, Cerovac N.Second-generation antipsychotics and extrapyramidal adverse effects.BioMed Res Int. 2014;2014:1-6. doi:10.1155/2014/656370

5 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Seeman P.Cannabidiol is a partial agonist at dopamine D2High receptors, predicting its antipsychotic clinical dose.Transl Psychiatry. 2016;6(10):e920-e920. doi:10.1038/tp.2016.195National Alliance on Mental Illness.Aripiprazole (Abilify).Ribeiro ELA, de Mendonça Lima T, Vieira MEB, Storpirtis S, Aguiar PM.Efficacy and safety of aripiprazole for the treatment of schizophrenia: an overview of systematic reviews.Eur J Clin Pharmacol. 2018;74(10):1215-1233. doi:10.1007/s00228-018-2498-1FDA.Highlights of prescribing information: Abilify.Divac N, Prostran M, Jakovcevski I, Cerovac N.Second-generation antipsychotics and extrapyramidal adverse effects.BioMed Res Int. 2014;2014:1-6. doi:10.1155/2014/656370

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Seeman P.Cannabidiol is a partial agonist at dopamine D2High receptors, predicting its antipsychotic clinical dose.Transl Psychiatry. 2016;6(10):e920-e920. doi:10.1038/tp.2016.195National Alliance on Mental Illness.Aripiprazole (Abilify).Ribeiro ELA, de Mendonça Lima T, Vieira MEB, Storpirtis S, Aguiar PM.Efficacy and safety of aripiprazole for the treatment of schizophrenia: an overview of systematic reviews.Eur J Clin Pharmacol. 2018;74(10):1215-1233. doi:10.1007/s00228-018-2498-1FDA.Highlights of prescribing information: Abilify.Divac N, Prostran M, Jakovcevski I, Cerovac N.Second-generation antipsychotics and extrapyramidal adverse effects.BioMed Res Int. 2014;2014:1-6. doi:10.1155/2014/656370

Seeman P.Cannabidiol is a partial agonist at dopamine D2High receptors, predicting its antipsychotic clinical dose.Transl Psychiatry. 2016;6(10):e920-e920. doi:10.1038/tp.2016.195

National Alliance on Mental Illness.Aripiprazole (Abilify).

Ribeiro ELA, de Mendonça Lima T, Vieira MEB, Storpirtis S, Aguiar PM.Efficacy and safety of aripiprazole for the treatment of schizophrenia: an overview of systematic reviews.Eur J Clin Pharmacol. 2018;74(10):1215-1233. doi:10.1007/s00228-018-2498-1

FDA.Highlights of prescribing information: Abilify.

Divac N, Prostran M, Jakovcevski I, Cerovac N.Second-generation antipsychotics and extrapyramidal adverse effects.BioMed Res Int. 2014;2014:1-6. doi:10.1155/2014/656370

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